Replace undo impl: replace undoers with cmds

Undoers were little objects to swap/revert an action. They didn't
execute the action itself, they just revert its previous state. Now
undoers were replaced with cmds: A cmd is an object that
executes/undoes/redoes just one action.

Changes:
* Remove old undo library and app/objects_container_impl.cpp
  (now we use the doc::ObjectId directly to store undo info)
* Remove all Undoers from app/undoers/
* Replace DocumentApi impl with little Cmds in app/cmd/, these
  cmds handle execute/undo/redo of each action at the logic layer
* Remove doc::Dirty object
* Remove doc::Settings: all undo configuration is in the app side
* Move undo options from app:ISettings to app::Preferences
* Rename UndoTransaction to Transaction
* Create a CmdSequence to store a sequence of Cmds (as now the new
  undo library doesn't support open/close groups)
* Add doc::get<T>(ObjectId) function to get any kind of object
  from the doc library by its ID
* Add Cel::document() and Sprite::document() members
* Add Sprite::cels(frame_t) to get all cels in the given frame
* Add Layer::displaceFrames() member function
* Move the "allow non-linear history" flag from undo2::UndoHistory
  to app::DocumentUndo

TODO.md

@@ -43,6 +43,9 @@
 
 # Refactoring
 
+* Remove unused skin parts
+* Make one level of layers (folders should modify only timeline/UI)
+* rename undo2 to undo
 * Convert doc::PixelFormat to a enum class
 * Add doc::Spec with width/height/channels/ColorMode/ncolors
 * Convert doc::LayerIndex -> typedef int doc::layer_t;

data/gui.xml

@@ -624,7 +624,7 @@
       <item command="BackgroundFromLayer" text="&amp;Background from Layer" />
       <item command="LayerFromBackground" text="&amp;Layer from Background" />
       <separator />
-      <item command="DuplicateLayer" text="&amp;Duplicate..." />
+      <item command="DuplicateLayer" text="&amp;Duplicate" />
       <item command="MergeDownLayer" text="&amp;Merge Down" />
       <item command="FlattenLayers" text="&amp;Flatten" />
     </menu>

data/pref.xml

@@ -1,3 +1,5 @@
+<!-- Aseprite -->
+<!-- Copyright (C) 2014-2015 by David Capello -->
 <?xml version="1.0" encoding="utf-8"?>
 <preferences>
 
@@ -60,8 +62,9 @@
       <option id="expand_menubar_on_mouseover" type="bool" default="false" migrate="Options.ExpandMenuBarOnMouseover" />
     </section>
     <section id="undo" text="Undo">
-      <option id="size_limit" type="int" default="0" />
-      <option id="goto_modified" type="bool" default="false" />
+      <option id="size_limit" type="int" default="64" />
+      <option id="goto_modified" type="bool" default="true" />
+      <option id="allow_nonlinear_history" type="bool" default="false" />
     </section>
     <section id="editor" text="Editor">
       <option id="zoom_with_scroll_wheel" type="bool" default="false" form="" />

data/widgets/options.xml

@@ -1,5 +1,5 @@
 <!-- Aseprite -->
-<!-- Copyright (C) 2001-2014 by David Capello -->
+<!-- Copyright (C) 2001-2015 by David Capello -->
 <gui>
   <window id="options" text="Preferences">
   <vbox>
@@ -86,15 +86,16 @@
         <!-- Undo -->
         <vbox id="section_undo">
           <separator text="Undo" horizontal="true" />
-          <box horizontal="true">
+          <hbox>
             <label text="Undo Limit:" />
             <entry id="undo_size_limit" maxsize="4" tooltip="Limit of memory to be used&#10;for undo information per sprite.&#10;Specified in megabytes." />
             <label text="MB" />
-          </box>
+          </hbox>
 
-          <box horizontal="true">
+          <vbox>
             <check id="undo_goto_modified" text="Go to modified frame/layer" tooltip="When it's enabled each time you undo/redo&#10;the current frame &amp; layer will be modified&#10;to focus the undid/redid change." />
-          </box>
+            <check id="undo_allow_nonlinear_history" text="Allow non-linear history." />
+          </vbox>
         </vbox>
 
         <!-- Experimental -->

src/CMakeLists.txt

@@ -1,5 +1,5 @@
 # Aseprite
-# Copyright (C) 2001-2014  David Capello
+# Copyright (C) 2001-2015  David Capello
 
 add_definitions(-DHAVE_CONFIG_H)
 
@@ -30,7 +30,6 @@ set(aseprite_libraries
   doc-lib
   render-lib
   scripting-lib
-  undo-lib
   undo2-lib
   filters-lib
   ui-lib
@@ -220,7 +219,6 @@ add_subdirectory(gfx)
 add_subdirectory(scripting)
 add_subdirectory(she)
 add_subdirectory(ui)
-add_subdirectory(undo)
 add_subdirectory(undo2)
 
 add_subdirectory(app)

src/README.md

@@ -18,8 +18,7 @@ because they don't depend on any other component.
   * [css](css/): Pseudo-style sheet library.
   * [gfx](gfx/): Abstract graphics structures like point, size, rectangle, region, color, etc.
   * [scripting](scripting/): JavaScript engine ([V8](https://code.google.com/p/v8/)).
-  * [undo](undo/): Generic library to manage undo history of undoable actions.
-  * [undo2](undo2/): New library to replace the old undo system.
+  * [undo2](undo2/): Generic library to manage a history of undoable commands.
 
 ## Level 1
 

src/app/CMakeLists.txt

@@ -1,5 +1,5 @@
 # Aseprite
-# Copyright (C) 2001-2014  David Capello
+# Copyright (C) 2001-2015  David Capello
 
 ######################################################################
 # Generate source files from widget XML files
@@ -53,6 +53,56 @@ add_library(app-lib
   app_render.cpp
   backup.cpp
   check_update.cpp
+  cmd.cpp
+  cmd/add_cel.cpp
+  cmd/add_frame.cpp
+  cmd/add_layer.cpp
+  cmd/add_palette.cpp
+  cmd/background_from_layer.cpp
+  cmd/clear_cel.cpp
+  cmd/clear_image.cpp
+  cmd/clear_mask.cpp
+  cmd/configure_background.cpp
+  cmd/copy_cel.cpp
+  cmd/copy_frame.cpp
+  cmd/copy_rect.cpp
+  cmd/copy_region.cpp
+  cmd/deselect_mask.cpp
+  cmd/flatten_layers.cpp
+  cmd/flip_image.cpp
+  cmd/flip_mask.cpp
+  cmd/flip_masked_cel.cpp
+  cmd/layer_from_background.cpp
+  cmd/move_cel.cpp
+  cmd/move_layer.cpp
+  cmd/object_io.cpp
+  cmd/remove_cel.cpp
+  cmd/remove_frame.cpp
+  cmd/remove_layer.cpp
+  cmd/remove_palette.cpp
+  cmd/replace_image.cpp
+  cmd/reselect_mask.cpp
+  cmd/set_cel_frame.cpp
+  cmd/set_cel_opacity.cpp
+  cmd/set_cel_position.cpp
+  cmd/set_frame_duration.cpp
+  cmd/set_layer_flags.cpp
+  cmd/set_layer_name.cpp
+  cmd/set_mask.cpp
+  cmd/set_mask_position.cpp
+  cmd/set_palette.cpp
+  cmd/set_pixel_format.cpp
+  cmd/set_sprite_size.cpp
+  cmd/set_total_frames.cpp
+  cmd/set_transparent_color.cpp
+  cmd/with_cel.cpp
+  cmd/with_document.cpp
+  cmd/with_image.cpp
+  cmd/with_layer.cpp
+  cmd/with_palette.cpp
+  cmd/with_sprite.cpp
+  cmd_sequence.cpp
+  cmd_transaction.cpp
   color.cpp
   color_picker.cpp
   color_swatches.cpp
@@ -189,7 +239,6 @@ add_library(app-lib
   modules/gfx.cpp
   modules/gui.cpp
   modules/palettes.cpp
-  objects_container_impl.cpp
   pref/preferences.cpp
   project.cpp
   recent_files.cpp
@@ -206,6 +255,7 @@ add_library(app-lib
   tools/shade_table.cpp
   tools/tool_box.cpp
   tools/tool_loop_manager.cpp
+  transaction.cpp
   ui/app_menuitem.cpp
   ui/button_set.cpp
   ui/color_bar.cpp
@@ -262,38 +312,6 @@ add_library(app-lib
   ui/workspace.cpp
   ui/workspace_part.cpp
   ui_context.cpp
-  undo_transaction.cpp
-  undoers/add_cel.cpp
-  undoers/add_frame.cpp
-  undoers/add_layer.cpp
-  undoers/add_palette.cpp
-  undoers/close_group.cpp
-  undoers/dirty_area.cpp
-  undoers/flip_image.cpp
-  undoers/image_area.cpp
-  undoers/modified_region.cpp
-  undoers/move_layer.cpp
-  undoers/object_io.cpp
-  undoers/open_group.cpp
-  undoers/remap_palette.cpp
-  undoers/remove_cel.cpp
-  undoers/remove_frame.cpp
-  undoers/remove_layer.cpp
-  undoers/remove_palette.cpp
-  undoers/replace_image.cpp
-  undoers/set_cel_frame.cpp
-  undoers/set_cel_opacity.cpp
-  undoers/set_cel_position.cpp
-  undoers/set_frame_duration.cpp
-  undoers/set_layer_flags.cpp
-  undoers/set_layer_name.cpp
-  undoers/set_mask.cpp
-  undoers/set_mask_position.cpp
-  undoers/set_palette_colors.cpp
-  undoers/set_sprite_pixel_format.cpp
-  undoers/set_sprite_size.cpp
-  undoers/set_sprite_transparent_color.cpp
-  undoers/set_total_frames.cpp
   util/autocrop.cpp
   util/boundary.cpp
   util/clipboard.cpp

src/app/cmd.cpp

@@ -0,0 +1,116 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd.h"
+
+namespace app {
+
+Cmd::Cmd()
+#if _DEBUG
+  : m_state(State::NotExecuted)
+#endif
+{
+}
+
+Cmd::~Cmd()
+{
+}
+
+void Cmd::execute(Context* ctx)
+{
+  ASSERT(m_state == State::NotExecuted);
+
+  m_ctx = ctx;
+
+  onExecute();
+  onFireNotifications();
+
+#if _DEBUG
+  m_state = State::Executed;
+#endif
+}
+
+void Cmd::undo()
+{
+  ASSERT(m_state == State::Executed || m_state == State::Redone);
+
+  onUndo();
+  onFireNotifications();
+
+#if _DEBUG
+  m_state = State::Undone;
+#endif
+}
+
+void Cmd::redo()
+{
+  ASSERT(m_state == State::Undone);
+
+  onRedo();
+  onFireNotifications();
+
+#if _DEBUG
+  m_state = State::Redone;
+#endif
+}
+
+std::string Cmd::label() const
+{
+  return onLabel();
+}
+
+size_t Cmd::memSize() const
+{
+  return onMemSize();
+}
+
+void Cmd::onExecute()
+{
+  // Do nothing
+}
+
+void Cmd::onUndo()
+{
+  // Do nothing
+}
+
+void Cmd::onRedo()
+{
+  // By default onRedo() uses onExecute() implementation
+  onExecute();
+}
+
+void Cmd::onFireNotifications()
+{
+  // Do nothing
+}
+
+std::string Cmd::onLabel() const
+{
+  return "";
+}
+
+size_t Cmd::onMemSize() const {
+  return sizeof(*this);
+}
+
+} // namespace app

src/app/cmd.h

@@ -0,0 +1,62 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_H_INCLUDED
+#define APP_CMD_H_INCLUDED
+#pragma once
+
+#include "doc/sprite_position.h"
+#include "undo2/undo_command.h"
+
+#include <string>
+
+namespace app {
+  class Context;
+
+  class Cmd : public undo2::UndoCommand {
+  public:
+    Cmd();
+    virtual ~Cmd();
+
+    void execute(Context* ctx);
+    void undo() override;
+    void redo() override;
+    std::string label() const;
+    size_t memSize() const;
+
+    Context* context() const { return m_ctx; }
+
+  protected:
+    virtual void onExecute();
+    virtual void onUndo();
+    virtual void onRedo();
+    virtual void onFireNotifications();
+    virtual std::string onLabel() const;
+    virtual size_t onMemSize() const;
+
+  private:
+    Context* m_ctx;
+#if _DEBUG
+    enum class State { NotExecuted, Executed, Undone, Redone };
+    State m_state;
+#endif
+  };
+
+} // namespace app
+
+#endif

src/app/cmd/README.md

@@ -0,0 +1,11 @@
+## Shared pointers
+
+Do not keep `ImageRef` or any kind of smart pointer to `doc::`
+entities. As several `cmd` can persist in parallel with other `cmd`
+(due the tree structure of the [undo history](../../undo2/undo_history.h))
+these smart pointers can generate conflicts in the logic layer.
+E.g. If we keep an `ImageRef` inside a `cmd`, the image is
+not removed from the [objects hash table](../../doc/object.cpp),
+so two or more `cmd` could will try to add/remove the same object
+in the hash table (there are asserts to check this state, were
+someone is trying to add the same `ObjectId` in the hash table).

src/app/cmd/add_cel.cpp

@@ -0,0 +1,97 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/add_cel.h"
+
+#include "app/cmd/object_io.h"
+#include "doc/cel.h"
+#include "doc/document.h"
+#include "doc/document_event.h"
+#include "doc/layer.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+AddCel::AddCel(Layer* layer, Cel* cel)
+  : WithLayer(layer)
+  , WithCel(cel)
+{
+}
+
+void AddCel::onExecute()
+{
+  Layer* layer = this->layer();
+  Cel* cel = this->cel();
+
+  addCel(layer, cel);
+}
+
+void AddCel::onUndo()
+{
+  Layer* layer = this->layer();
+  Cel* cel = this->cel();
+
+  ObjectIO(layer->sprite()).write_cel(m_stream, cel);
+
+  removeCel(layer, cel);
+}
+
+void AddCel::onRedo()
+{
+  Layer* layer = this->layer();
+  Cel* cel = ObjectIO(layer->sprite()).read_cel(m_stream);
+
+  addCel(layer, cel);
+
+  m_stream.str(std::string());
+  m_stream.clear();
+}
+
+void AddCel::addCel(Layer* layer, Cel* cel)
+{
+  static_cast<LayerImage*>(layer)->addCel(cel);
+
+  Document* doc = cel->document();
+  DocumentEvent ev(doc);
+  ev.sprite(layer->sprite());
+  ev.layer(layer);
+  ev.cel(cel);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onAddCel, ev);
+}
+
+void AddCel::removeCel(Layer* layer, Cel* cel)
+{
+  Document* doc = cel->document();
+  DocumentEvent ev(doc);
+  ev.sprite(layer->sprite());
+  ev.layer(layer);
+  ev.cel(cel);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onRemoveCel, ev);
+
+  static_cast<LayerImage*>(layer)->removeCel(cel);
+  delete cel;
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/add_cel.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,38 +16,48 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_ADD_LAYER_H_INCLUDED
-#define APP_UNDOERS_ADD_LAYER_H_INCLUDED
+#ifndef APP_CMD_ADD_CEL_H_INCLUDED
+#define APP_CMD_ADD_CEL_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
-#include "undo/object_id.h"
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+#include "app/cmd/with_layer.h"
+
+#include <sstream>
 
 namespace doc {
+  class Cel;
   class Layer;
 }
 
 namespace app {
-  class Document;
+namespace cmd {
+  using namespace doc;
 
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+  class AddCel : public Cmd
+               , public WithLayer
+               , public WithCel {
+  public:
+    AddCel(Layer* layer, Cel* cel);
 
-    class AddLayer : public UndoerBase {
-    public:
-      AddLayer(ObjectsContainer* objects, Document* document, Layer* layer);
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) +
+        const_cast<std::stringstream*>(&m_stream)->tellp();
+    }
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  private:
+    void addCel(Layer* layer, Cel* cel);
+    void removeCel(Layer* layer, Cel* cel);
 
-    private:
-      undo::ObjectId m_documentId;
-      undo::ObjectId m_layerId;
-    };
+    std::stringstream m_stream;
+  };
 
-  } // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_ADD_LAYER_H_INCLUDED
+#endif

src/app/cmd/add_frame.cpp

@@ -0,0 +1,91 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/add_frame.h"
+
+#include "app/cmd/add_cel.h"
+#include "app/document.h"
+#include "doc/cel.h"
+#include "doc/document_event.h"
+#include "doc/layer.h"
+#include "doc/primitives.h"
+#include "doc/sprite.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+AddFrame::AddFrame(Sprite* sprite, frame_t newFrame)
+  : WithSprite(sprite)
+  , m_newFrame(newFrame)
+  , m_addCel(nullptr)
+{
+}
+
+void AddFrame::onExecute()
+{
+  Sprite* sprite = this->sprite();
+  app::Document* doc = static_cast<app::Document*>(sprite->document());
+
+  sprite->addFrame(m_newFrame);
+
+  if (m_addCel) {
+    m_addCel->redo();
+  }
+  else {
+    LayerImage* bglayer = sprite->backgroundLayer();
+    if (bglayer) {
+      ImageRef bgimage(Image::create(sprite->pixelFormat(), sprite->width(), sprite->height()));
+      clear_image(bgimage, doc->bgColor(bglayer));
+      Cel* cel = new Cel(m_newFrame, bgimage);
+      m_addCel.reset(new cmd::AddCel(bglayer, cel));
+      m_addCel->execute(context());
+    }
+  }
+
+  // Notify observers about the new frame.
+  DocumentEvent ev(doc);
+  ev.sprite(sprite);
+  ev.frame(m_newFrame);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onAddFrame, ev);
+}
+
+void AddFrame::onUndo()
+{
+  Sprite* sprite = this->sprite();
+  app::Document* doc = static_cast<app::Document*>(sprite->document());
+
+  if (m_addCel)
+    m_addCel->undo();
+
+  sprite->removeFrame(m_newFrame);
+
+  // Notify observers about the new frame.
+  DocumentEvent ev(doc);
+  ev.sprite(sprite);
+  ev.frame(m_newFrame);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onRemoveFrame, ev);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/add_frame.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,37 +16,44 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_ADD_PALETTE_H_INCLUDED
-#define APP_UNDOERS_ADD_PALETTE_H_INCLUDED
+#ifndef APP_CMD_ADD_FRAME_H_INCLUDED
+#define APP_CMD_ADD_FRAME_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
+#include "app/cmd.h"
+#include "app/cmd/add_cel.h"
+#include "app/cmd/with_sprite.h"
+#include "base/unique_ptr.h"
 #include "doc/frame.h"
-#include "undo/object_id.h"
 
 namespace doc {
   class Sprite;
 }
 
 namespace app {
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+namespace cmd {
+  using namespace doc;
 
-    class AddPalette : public UndoerBase {
-    public:
-      AddPalette(ObjectsContainer* objects, Sprite* sprite, frame_t palette_frame);
+  class AddFrame : public Cmd
+                 , public WithSprite {
+  public:
+    AddFrame(Sprite* sprite, frame_t frame);
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
 
-    private:
-      undo::ObjectId m_spriteId;
-      frame_t m_paletteFrame;
-    };
+  private:
+    void moveFrames(Layer* layer, frame_t fromThis, frame_t delta);
 
-  } // namespace undoers
+    frame_t m_newFrame;
+    base::UniquePtr<AddCel> m_addCel;
+  };
+
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_ADD_PALETTE_H_INCLUDED
+#endif

src/app/cmd/add_layer.cpp

@@ -0,0 +1,102 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/add_layer.h"
+
+#include "app/cmd/object_io.h"
+#include "doc/layer.h"
+#include "doc/document.h"
+#include "doc/document_event.h"
+#include "doc/layer.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+AddLayer::AddLayer(Layer* folder, Layer* newLayer, Layer* afterThis)
+  : m_folder(folder)
+  , m_newLayer(newLayer)
+  , m_afterThis(afterThis)
+{
+}
+
+void AddLayer::onExecute()
+{
+  Layer* folder = m_folder.layer();
+  Layer* newLayer = m_newLayer.layer();
+  Layer* afterThis = m_afterThis.layer();
+
+  addLayer(folder, newLayer, afterThis);
+}
+
+void AddLayer::onUndo()
+{
+  Layer* folder = m_folder.layer();
+  Layer* layer = m_newLayer.layer();
+
+  ObjectIO(folder->sprite()).write_layer(m_stream, layer);
+
+  removeLayer(folder, layer);
+}
+
+void AddLayer::onRedo()
+{
+  Layer* folder = m_folder.layer();
+  Layer* newLayer = ObjectIO(folder->sprite()).read_layer(m_stream);
+  Layer* afterThis = m_afterThis.layer();
+
+  addLayer(folder, newLayer, afterThis);
+
+  m_stream.str(std::string());
+  m_stream.clear();
+}
+
+void AddLayer::addLayer(Layer* folder, Layer* newLayer, Layer* afterThis)
+{
+  static_cast<LayerFolder*>(folder)->addLayer(newLayer);
+  static_cast<LayerFolder*>(folder)->stackLayer(newLayer, afterThis);
+
+  Document* doc = folder->sprite()->document();
+  DocumentEvent ev(doc);
+  ev.sprite(folder->sprite());
+  ev.layer(newLayer);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onAddLayer, ev);
+}
+
+void AddLayer::removeLayer(Layer* folder, Layer* layer)
+{
+  Document* doc = folder->sprite()->document();
+  DocumentEvent ev(doc);
+  ev.sprite(layer->sprite());
+  ev.layer(layer);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onBeforeRemoveLayer, ev);
+
+  static_cast<LayerFolder*>(folder)->removeLayer(layer);
+
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onAfterRemoveLayer, ev);
+
+  delete layer;
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/add_layer.h

@@ -0,0 +1,62 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_ADD_LAYER_H_INCLUDED
+#define APP_CMD_ADD_LAYER_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_layer.h"
+
+#include <sstream>
+
+namespace doc {
+  class Layer;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class AddLayer : public Cmd {
+  public:
+    AddLayer(Layer* folder, Layer* newLayer, Layer* afterThis);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) +
+        const_cast<std::stringstream*>(&m_stream)->tellp();
+    }
+
+  private:
+    void addLayer(Layer* folder, Layer* newLayer, Layer* afterThis);
+    void removeLayer(Layer* folder, Layer* layer);
+
+    WithLayer m_folder;
+    WithLayer m_newLayer;
+    WithLayer m_afterThis;
+    std::stringstream m_stream;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/add_palette.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,38 +20,52 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/add_palette.h"
+#include "app/cmd/add_palette.h"
 
-#include "app/undoers/remove_palette.h"
 #include "doc/sprite.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
+#include "doc/palette.h"
+#include "doc/palette_io.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
+using namespace doc;
 
-AddPalette::AddPalette(ObjectsContainer* objects, Sprite* sprite, frame_t paletteFrame)
-  : m_spriteId(objects->addObject(sprite))
-  , m_paletteFrame(paletteFrame)
+AddPalette::AddPalette(Sprite* sprite, Palette* pal)
+  : WithSprite(sprite)
+  , WithPalette(pal)
 {
 }
 
-void AddPalette::dispose()
+void AddPalette::onExecute()
 {
-  delete this;
+  Sprite* sprite = this->sprite();
+  Palette* palette = this->palette();
+
+  sprite->setPalette(palette, true);
 }
 
-void AddPalette::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void AddPalette::onUndo()
 {
-  Sprite* sprite = objects->getObjectT<Sprite>(m_spriteId);
-  Palette* palette = sprite->palette(frame_t(m_paletteFrame));
+  Sprite* sprite = this->sprite();
+  Palette* pal = this->palette();
 
-  redoers->pushUndoer(new RemovePalette(objects, sprite, frame_t(m_paletteFrame)));
+  write_palette(m_stream, pal);
 
-  sprite->deletePalette(palette);
+  sprite->deletePalette(pal);
+  delete pal;
 }
 
-} // namespace undoers
+void AddPalette::onRedo()
+{
+  Sprite* sprite = this->sprite();
+  Palette* pal = read_palette(m_stream);
+
+  sprite->setPalette(pal, true);
+
+  m_stream.str(std::string());
+  m_stream.clear();
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/add_palette.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,13 +16,14 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_SET_TOTAL_FRAMES_H_INCLUDED
-#define APP_UNDOERS_SET_TOTAL_FRAMES_H_INCLUDED
+#ifndef APP_CMD_ADD_PALETTE_H_INCLUDED
+#define APP_CMD_ADD_PALETTE_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
+#include "app/cmd.h"
+#include "app/cmd/with_palette.h"
+#include "app/cmd/with_sprite.h"
 #include "doc/frame.h"
-#include "undo/object_id.h"
 
 #include <sstream>
 
@@ -31,27 +32,30 @@ namespace doc {
 }
 
 namespace app {
-  class Document;
+namespace cmd {
+  using namespace doc;
 
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+  class AddPalette : public Cmd
+                   , public WithSprite
+                   , public WithPalette {
+  public:
+    AddPalette(Sprite* sprite, Palette* pal);
 
-    class SetTotalFrames : public UndoerBase {
-    public:
-      SetTotalFrames(ObjectsContainer* objects, Document* document, Sprite* sprite);
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) +
+        const_cast<std::stringstream*>(&m_stream)->tellp();
+    }
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  private:
+    frame_t m_frame;
+    std::stringstream m_stream;
+  };
 
-    private:
-      undo::ObjectId m_documentId;
-      undo::ObjectId m_spriteId;
-      frame_t m_totalFrames;
-    };
-
-  } // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_SET_TOTAL_FRAMES_H_INCLUDED
+#endif  // CMD_ADD_PALETTE_H_INCLUDED

src/app/cmd/background_from_layer.cpp

@@ -0,0 +1,110 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/background_from_layer.h"
+
+#include "app/cmd/add_cel.h"
+#include "app/cmd/configure_background.h"
+#include "app/cmd/copy_rect.h"
+#include "app/cmd/replace_image.h"
+#include "app/cmd/set_cel_position.h"
+#include "app/document.h"
+#include "doc/cel.h"
+#include "doc/image.h"
+#include "doc/layer.h"
+#include "doc/primitives.h"
+#include "doc/sprite.h"
+#include "render/render.h"
+
+namespace app {
+namespace cmd {
+
+BackgroundFromLayer::BackgroundFromLayer(Layer* layer)
+  : WithLayer(layer)
+{
+  ASSERT(layer);
+  ASSERT(layer->isVisible());
+  ASSERT(layer->isEditable());
+  ASSERT(layer->sprite() != NULL);
+  ASSERT(layer->sprite()->backgroundLayer() == NULL);
+}
+
+void BackgroundFromLayer::onExecute()
+{
+  Layer* layer = this->layer();
+  Sprite* sprite = layer->sprite();
+  app::Document* doc = static_cast<app::Document*>(sprite->document());
+  color_t bgcolor = doc->bgColor();
+
+  // create a temporary image to draw each frame of the new
+  // `Background' layer
+  ImageRef bg_image(Image::create(sprite->pixelFormat(),
+      sprite->width(),
+      sprite->height()));
+
+  CelList cels;
+  layer->getCels(cels);
+  for (Cel* cel : cels) {
+    // get the image from the sprite's stock of images
+    Image* cel_image = cel->image();
+    ASSERT(cel_image);
+
+    clear_image(bg_image, bgcolor);
+    render::composite_image(bg_image, cel_image,
+      cel->x(), cel->y(),
+      MID(0, cel->opacity(), 255),
+      static_cast<LayerImage*>(layer)->getBlendMode());
+
+    // now we have to copy the new image (bg_image) to the cel...
+    executeAndAdd(new cmd::SetCelPosition(cel, 0, 0));
+
+    // same size of cel-image and bg-image
+    if (bg_image->width() == cel_image->width() &&
+        bg_image->height() == cel_image->height()) {
+      executeAndAdd(new CopyRect(cel_image, bg_image,
+          gfx::Clip(0, 0, cel_image->bounds())));
+    }
+    else {
+      ImageRef bg_image2(Image::createCopy(bg_image));
+      executeAndAdd(new cmd::ReplaceImage(sprite, cel->imageRef(), bg_image2));
+    }
+  }
+
+  // Fill all empty cels with a flat-image filled with bgcolor
+  for (frame_t frame(0); frame<sprite->totalFrames(); ++frame) {
+    Cel* cel = layer->cel(frame);
+    if (!cel) {
+      ImageRef cel_image(Image::create(sprite->pixelFormat(),
+          sprite->width(), sprite->height()));
+      clear_image(cel_image, bgcolor);
+
+      // Create the new cel and add it to the new background layer
+      cel = new Cel(frame, cel_image);
+      executeAndAdd(new cmd::AddCel(layer, cel));
+    }
+  }
+
+  executeAndAdd(new cmd::ConfigureBackground(layer));
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/background_from_layer.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,25 +16,27 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_UNDOER_BASE_H_INCLUDED
-#define APP_UNDOERS_UNDOER_BASE_H_INCLUDED
+#ifndef APP_CMD_BACKGROUND_FROM_LAYER_H_INCLUDED
+#define APP_CMD_BACKGROUND_FROM_LAYER_H_INCLUDED
 #pragma once
 
-#include "undo/undoer.h"
+#include "app/cmd/with_layer.h"
+#include "app/cmd_sequence.h"
 
 namespace app {
-  namespace undoers {
+namespace cmd {
+  using namespace doc;
 
-    // Helper class to make new Undoers, derive from here and implement
-    // revert(), getMemSize(), and dispose() methods only.
-    class UndoerBase : public undo::Undoer {
-    public:
-      undo::Modification getModification() const override { return undo::DoesntModifyDocument; }
-      bool isOpenGroup() const override { return false; }
-      bool isCloseGroup() const override { return false; }
-    };
+  class BackgroundFromLayer : public CmdSequence
+                            , public WithLayer {
+  public:
+    BackgroundFromLayer(Layer* layer);
 
-  } // namespace undoers
+  protected:
+    void onExecute() override;
+  };
+
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_UNDOER_BASE_H_INCLUDED
+#endif

src/app/cmd/clear_cel.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,41 +20,50 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/add_cel.h"
+#include "app/cmd/clear_cel.h"
 
-#include "app/undoers/remove_cel.h"
+#include "app/cmd/clear_image.h"
+#include "app/cmd/remove_cel.h"
+#include "app/document.h"
 #include "doc/cel.h"
 #include "doc/layer.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
 using namespace doc;
-using namespace undo;
 
-AddCel::AddCel(ObjectsContainer* objects, Layer* layer, Cel* cel)
-  : m_layerId(objects->addObject(layer))
-  , m_celId(objects->addObject(cel))
+ClearCel::ClearCel(Cel* cel)
+  : WithCel(cel)
 {
+  app::Document* doc = static_cast<app::Document*>(cel->document());
+
+  if (cel->layer()->isBackground()) {
+    Image* image = cel->image();
+    ASSERT(image);
+    if (image)
+      m_seq.add(new cmd::ClearImage(image,
+          doc->bgColor(cel->layer())));
+  }
+  else {
+    m_seq.add(new cmd::RemoveCel(cel));
+  }
 }
 
-void AddCel::dispose()
+void ClearCel::onExecute()
 {
-  delete this;
+  m_seq.execute(context());
 }
 
-void AddCel::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void ClearCel::onUndo()
 {
-  LayerImage* layer = objects->getObjectT<LayerImage>(m_layerId);
-  Cel* cel = objects->getObjectT<Cel>(m_celId);
-
-  redoers->pushUndoer(new RemoveCel(objects, layer, cel));
-
-  layer->removeCel(cel);
-  delete cel;
+  m_seq.undo();
 }
 
-} // namespace undoers
+void ClearCel::onRedo()
+{
+  m_seq.redo();
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/clear_cel.h

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_CLEAR_CEL_H_INCLUDED
+#define APP_CMD_CLEAR_CEL_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+#include "app/cmd_sequence.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class ClearCel : public Cmd
+                 , public WithCel {
+  public:
+    ClearCel(Cel* cel);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) + m_seq.memSize();
+    }
+
+  private:
+    CmdSequence m_seq;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/clear_image.cpp

@@ -0,0 +1,54 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/clear_image.h"
+
+#include "app/document.h"
+#include "doc/image.h"
+#include "doc/primitives.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+ClearImage::ClearImage(Image* image, color_t color)
+  : WithImage(image)
+  , m_color(color)
+{
+}
+
+void ClearImage::onExecute()
+{
+  ASSERT(!m_copy);
+  m_copy.reset(Image::createCopy(image()));
+  clear_image(image(), m_color);
+}
+
+void ClearImage::onUndo()
+{
+  copy_image(image(), m_copy);
+  m_copy.reset(nullptr);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/clear_image.h

@@ -0,0 +1,52 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_CLEAR_IMAGE_H_INCLUDED
+#define APP_CMD_CLEAR_IMAGE_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_image.h"
+#include "doc/color.h"
+#include "doc/image_ref.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class ClearImage : public Cmd
+                   , public WithImage {
+  public:
+    ClearImage(Image* image, color_t color);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) + (m_copy ? m_copy->getMemSize(): 0);
+    }
+
+  private:
+    ImageRef m_copy;
+    color_t m_color;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/clear_mask.cpp

@@ -0,0 +1,131 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/clear_mask.h"
+
+#include "app/cmd/clear_cel.h"
+#include "app/document.h"
+#include "doc/cel.h"
+#include "doc/image.h"
+#include "doc/image_bits.h"
+#include "doc/layer.h"
+#include "doc/mask.h"
+#include "doc/primitives.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+ClearMask::ClearMask(Cel* cel)
+  : WithCel(cel)
+{
+  app::Document* doc = static_cast<app::Document*>(cel->document());
+
+  // If the mask is empty or is not visible then we have to clear the
+  // entire image in the cel.
+  if (!doc->isMaskVisible()) {
+    m_seq.add(new cmd::ClearCel(cel));
+    return;
+  }
+
+  Image* image = (cel ? cel->image(): NULL);
+  if (!image)
+    return;
+
+  Mask* mask = doc->mask();
+  m_offsetX = mask->bounds().x - cel->x();
+  m_offsetY = mask->bounds().y - cel->y();
+
+  gfx::Rect bounds =
+    image->bounds().createIntersect(
+      gfx::Rect(
+        m_offsetX, m_offsetY,
+        mask->bounds().w, mask->bounds().h));
+  if (bounds.isEmpty())
+    return;
+
+  m_dstImage.reset(new WithImage(image));
+  m_bgcolor = doc->bgColor(cel->layer());
+
+  m_copy.reset(crop_image(image,
+      bounds.x, bounds.y, bounds.w, bounds.h, m_bgcolor));
+}
+
+void ClearMask::onExecute()
+{
+  m_seq.execute(context());
+  if (m_dstImage)
+    clear();
+}
+
+void ClearMask::onUndo()
+{
+  if (m_dstImage)
+    restore();
+  m_seq.undo();
+}
+
+void ClearMask::onRedo()
+{
+  m_seq.redo();
+  if (m_dstImage)
+    clear();
+}
+
+void ClearMask::clear()
+{
+  Cel* cel = this->cel();
+  Image* image = m_dstImage->image();
+  app::Document* doc = static_cast<app::Document*>(cel->document());
+  Mask* mask = doc->mask();
+
+  ASSERT(mask->bitmap());
+  if (!mask->bitmap())
+    return;
+
+  const LockImageBits<BitmapTraits> maskBits(mask->bitmap());
+  LockImageBits<BitmapTraits>::const_iterator it = maskBits.begin();
+
+  // Clear the masked zones
+  int u, v;
+  for (v=0; v<mask->bounds().h; ++v) {
+    for (u=0; u<mask->bounds().w; ++u, ++it) {
+      ASSERT(it != maskBits.end());
+      if (*it) {
+        put_pixel(image,
+          u + m_offsetX,
+          v + m_offsetY, m_bgcolor);
+      }
+    }
+  }
+
+  ASSERT(it == maskBits.end());
+}
+
+void ClearMask::restore()
+{
+  copy_image(m_dstImage->image(), m_copy, m_offsetX, m_offsetY);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/clear_mask.h

@@ -0,0 +1,62 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_CLEAR_MASK_H_INCLUDED
+#define APP_CMD_CLEAR_MASK_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+#include "app/cmd/with_image.h"
+#include "app/cmd_sequence.h"
+#include "base/unique_ptr.h"
+#include "doc/image_ref.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class ClearMask : public Cmd
+                  , public WithCel {
+  public:
+    ClearMask(Cel* cel);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) + m_seq.memSize() +
+        (m_copy ? m_copy->getMemSize(): 0);
+    }
+
+  private:
+    void clear();
+    void restore();
+
+    CmdSequence m_seq;
+    base::UniquePtr<WithImage> m_dstImage;
+    ImageRef m_copy;
+    int m_offsetX, m_offsetY;
+    color_t m_bgcolor;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/configure_background.cpp

@@ -0,0 +1,44 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/configure_background.h"
+
+#include "app/cmd/move_layer.h"
+#include "app/cmd/set_layer_flags.h"
+#include "app/cmd/set_layer_name.h"
+
+namespace app {
+namespace cmd {
+
+ConfigureBackground::ConfigureBackground(Layer* layer)
+{
+  // Add "Background" and "LockMove" flags
+  LayerFlags newFlags = LayerFlags(int(layer->flags())
+    | int(LayerFlags::BackgroundLayerFlags));
+
+  add(new cmd::SetLayerFlags(layer, newFlags));
+  add(new cmd::SetLayerName(layer, "Background"));
+  add(new cmd::MoveLayer(layer, nullptr));
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/configure_background.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,37 +16,26 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_SET_CEL_POSITION_H_INCLUDED
-#define APP_UNDOERS_SET_CEL_POSITION_H_INCLUDED
+#ifndef APP_CMD_CONFIGURE_BACKGROUND_H_INCLUDED
+#define APP_CMD_CONFIGURE_BACKGROUND_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
-#include "undo/object_id.h"
+#include "app/cmd_sequence.h"
 
 namespace doc {
-  class Cel;
   class Layer;
 }
 
 namespace app {
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+namespace cmd {
+  using namespace doc;
 
-    class SetCelPosition : public UndoerBase {
-    public:
-      SetCelPosition(ObjectsContainer* objects, Cel* cel);
+  class ConfigureBackground : public CmdSequence {
+  public:
+    ConfigureBackground(Layer* layer);
+  };
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
-
-    private:
-      undo::ObjectId m_celId;
-      int m_x, m_y;
-    };
-
-  } // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_SET_CEL_POSITION_H_INCLUDED
+#endif

src/app/cmd/copy_cel.cpp

@@ -0,0 +1,131 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/copy_cel.h"
+
+#include "app/cmd/add_cel.h"
+#include "app/cmd/add_frame.h"
+#include "app/cmd/clear_cel.h"
+#include "app/cmd/copy_rect.h"
+#include "app/cmd/remove_cel.h"
+#include "app/document.h"
+#include "doc/cel.h"
+#include "doc/layer.h"
+#include "doc/primitives.h"
+#include "doc/sprite.h"
+#include "render/render.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+CopyCel::CopyCel(
+  LayerImage* srcLayer, frame_t srcFrame,
+  LayerImage* dstLayer, frame_t dstFrame)
+  : m_srcLayer(srcLayer)
+  , m_dstLayer(dstLayer)
+  , m_srcFrame(srcFrame)
+  , m_dstFrame(dstFrame)
+{
+}
+
+void CopyCel::onExecute()
+{
+  LayerImage* srcLayer = static_cast<LayerImage*>(m_srcLayer.layer());
+  LayerImage* dstLayer = static_cast<LayerImage*>(m_dstLayer.layer());
+
+  ASSERT(srcLayer);
+  ASSERT(dstLayer);
+
+  Sprite* srcSprite = srcLayer->sprite();
+  Sprite* dstSprite = dstLayer->sprite();
+  ASSERT(srcSprite);
+  ASSERT(dstSprite);
+  ASSERT(m_srcFrame >= 0 && m_srcFrame < srcSprite->totalFrames());
+  ASSERT(m_dstFrame >= 0);
+  (void)srcSprite;              // To avoid unused variable warning on Release mode
+
+  Cel* srcCel = srcLayer->cel(m_srcFrame);
+  Cel* dstCel = dstLayer->cel(m_dstFrame);
+
+  // Clear destination cel if it does exist. It'll be overriden by the
+  // copy of srcCel.
+  if (dstCel)
+    executeAndAdd(new cmd::ClearCel(dstCel));
+
+  // Add empty frames until newFrame
+  while (dstSprite->totalFrames() <= m_dstFrame)
+    executeAndAdd(new cmd::AddFrame(dstSprite, dstSprite->totalFrames()));
+
+  Image* srcImage = (srcCel ? srcCel->image(): NULL);
+  ImageRef dstImage;
+  dstCel = dstLayer->cel(m_dstFrame);
+  if (dstCel)
+    dstImage = dstCel->imageRef();
+
+  if (dstLayer->isBackground()) {
+    if (srcCel) {
+      ASSERT(dstImage);
+      if (dstImage) {
+        int blend = (srcLayer->isBackground() ?
+          BLEND_MODE_COPY: BLEND_MODE_NORMAL);
+
+        ImageRef tmp(Image::createCopy(dstImage));
+        render::composite_image(tmp, srcImage,
+          srcCel->x(), srcCel->y(), 255, blend);
+        executeAndAdd(new cmd::CopyRect(dstImage, tmp, gfx::Clip(tmp->bounds())));
+      }
+    }
+    else {
+      ASSERT(dstCel);
+      if (dstCel)
+        executeAndAdd(new cmd::ClearCel(dstCel));
+    }
+  }
+  else {
+    if (dstCel)
+      executeAndAdd(new cmd::RemoveCel(dstCel));
+
+    if (srcCel) {
+      dstImage.reset(Image::createCopy(srcImage));
+
+      dstCel = new Cel(*srcCel);
+      dstCel->setFrame(m_dstFrame);
+      dstCel->setImage(dstImage);
+
+      executeAndAdd(new cmd::AddCel(dstLayer, dstCel));
+    }
+  }
+}
+
+void CopyCel::onFireNotifications()
+{
+  CmdSequence::onFireNotifications();
+  static_cast<app::Document*>(m_dstLayer.layer()->sprite()->document())
+    ->notifyCelCopied(
+      m_srcLayer.layer(), m_srcFrame,
+      m_dstLayer.layer(), m_dstFrame);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/copy_cel.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,39 +16,39 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_SET_CEL_FRAME_H_INCLUDED
-#define APP_UNDOERS_SET_CEL_FRAME_H_INCLUDED
+#ifndef APP_CMD_COPY_CEL_H_INCLUDED
+#define APP_CMD_COPY_CEL_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
+#include "app/cmd/with_layer.h"
+#include "app/cmd_sequence.h"
+#include "doc/color.h"
 #include "doc/frame.h"
-#include "undo/object_id.h"
 
 namespace doc {
-  class Cel;
   class LayerImage;
 }
 
 namespace app {
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+namespace cmd {
+  using namespace doc;
 
-    class SetCelFrame : public UndoerBase {
-    public:
-      SetCelFrame(ObjectsContainer* objects, LayerImage* layer, Cel* cel);
+  class CopyCel : public CmdSequence {
+  public:
+    CopyCel(
+      LayerImage* srcLayer, frame_t srcFrame,
+      LayerImage* dstLayer, frame_t dstFrame);
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  protected:
+    void onExecute() override;
+    void onFireNotifications() override;
 
-    private:
-      undo::ObjectId m_layerId;
-      undo::ObjectId m_celId;
-      frame_t m_frame;
-    };
+  private:
+    WithLayer m_srcLayer, m_dstLayer;
+    frame_t m_srcFrame, m_dstFrame;
+  };
 
-  } // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_SET_CEL_FRAME_H_INCLUDED
+#endif

src/app/cmd/copy_frame.cpp

@@ -0,0 +1,66 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/copy_frame.h"
+
+#include "app/cmd/add_frame.h"
+#include "app/cmd/copy_cel.h"
+#include "app/cmd/set_frame_duration.h"
+#include "doc/sprite.h"
+#include "doc/layer.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+CopyFrame::CopyFrame(Sprite* sprite, frame_t fromFrame, frame_t newFrame)
+  : WithSprite(sprite)
+  , m_fromFrame(fromFrame)
+  , m_newFrame(newFrame)
+{
+}
+
+void CopyFrame::onExecute()
+{
+  Sprite* sprite = this->sprite();
+  frame_t fromFrame = m_fromFrame;
+  int msecs = sprite->frameDuration(fromFrame);
+
+  executeAndAdd(new cmd::AddFrame(sprite, m_newFrame));
+  executeAndAdd(new cmd::SetFrameDuration(sprite, m_newFrame, msecs));
+
+  if (fromFrame >= m_newFrame)
+    ++fromFrame;
+
+  for (int i=0; i<sprite->countLayers(); ++i) {
+    Layer* layer = sprite->layer(i);
+    if (layer->isImage())  {
+      executeAndAdd(new cmd::CopyCel(
+          static_cast<LayerImage*>(layer), fromFrame,
+          static_cast<LayerImage*>(layer), m_newFrame));
+    }
+  }
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/copy_frame.h

@@ -0,0 +1,52 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_COPY_FRAME_H_INCLUDED
+#define APP_CMD_COPY_FRAME_H_INCLUDED
+#pragma once
+
+#include "app/cmd_sequence.h"
+#include "app/cmd/with_sprite.h"
+#include "doc/frame.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class CopyFrame : public CmdSequence
+                  , public WithSprite {
+  public:
+    CopyFrame(Sprite* sprite, frame_t fromFrame, frame_t newFrame);
+
+  protected:
+    void onExecute() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) +
+        CmdSequence::onMemSize() - sizeof(CmdSequence);
+    }
+
+  private:
+    frame_t m_fromFrame;
+    frame_t m_newFrame;
+    bool m_firstTime;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/copy_rect.cpp

@@ -0,0 +1,99 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/copy_rect.h"
+
+#include "doc/image.h"
+
+#include <algorithm>
+
+namespace app {
+namespace cmd {
+
+CopyRect::CopyRect(Image* dst, const Image* src, const gfx::Clip& clip)
+  : WithImage(dst)
+  , m_clip(clip)
+{
+  if (!m_clip.clip(
+        dst->width(), dst->height(),
+        src->width(), src->height()))
+    return;
+
+  // Fill m_data with "src" data
+
+  int lineSize = src->getRowStrideSize(m_clip.size.w);
+  m_data.resize(lineSize * m_clip.size.h);
+
+  auto it = m_data.begin();
+  for (int v=0; v<m_clip.size.h; ++v) {
+    uint8_t* addr = src->getPixelAddress(
+      m_clip.dst.x, m_clip.dst.y+v);
+
+    std::copy(addr, addr+lineSize, it);
+    it += lineSize;
+  }
+}
+
+void CopyRect::onExecute()
+{
+  swap();
+}
+
+void CopyRect::onUndo()
+{
+  swap();
+}
+
+void CopyRect::onRedo()
+{
+  swap();
+}
+
+void CopyRect::swap()
+{
+  if (m_clip.size.w < 1 || m_clip.size.h < 1)
+    return;
+
+  Image* image = this->image();
+  int lineSize = this->lineSize();
+  std::vector<uint8_t> tmp(lineSize);
+
+  auto it = m_data.begin();
+  for (int v=0; v<m_clip.size.h; ++v) {
+    uint8_t* addr = image->getPixelAddress(
+      m_clip.dst.x, m_clip.dst.y+v);
+
+    std::copy(addr, addr+lineSize, tmp.begin());
+    std::copy(it, it+lineSize, addr);
+    std::copy(tmp.begin(), tmp.end(), it);
+
+    it += lineSize;
+  }
+}
+
+int CopyRect::lineSize()
+{
+  return image()->getRowStrideSize(m_clip.size.w);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/copy_rect.h

@@ -0,0 +1,61 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_COPY_RECT_H_INCLUDED
+#define APP_CMD_COPY_RECT_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_image.h"
+#include "gfx/clip.h"
+
+#include <vector>
+
+namespace doc {
+  class Image;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class CopyRect : public Cmd
+                 , public WithImage {
+  public:
+    CopyRect(Image* dst, const Image* src, const gfx::Clip& clip);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) + m_data.size();
+    }
+
+  private:
+    void swap();
+    int lineSize();
+
+    gfx::Clip m_clip;
+    std::vector<uint8_t> m_data;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/copy_region.cpp

@@ -0,0 +1,96 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/copy_region.h"
+
+#include "doc/image.h"
+
+#include <algorithm>
+
+namespace app {
+namespace cmd {
+
+CopyRegion::CopyRegion(Image* dst, Image* src,
+  const gfx::Region& region, int dst_dx, int dst_dy)
+  : WithImage(dst)
+{
+  // Save region pixels
+  for (const auto& rc : region) {
+    gfx::Clip clip(
+      rc.x+dst_dx, rc.y+dst_dy,
+      rc.x, rc.y, rc.w, rc.h);
+    if (!clip.clip(
+          dst->width(), dst->height(),
+          src->width(), src->height()))
+      continue;
+
+    m_region.createUnion(m_region, gfx::Region(clip.dstBounds()));
+
+    for (int y=0; y<clip.size.h; ++y)  {
+      m_stream.write(
+        (const char*)src->getPixelAddress(clip.src.x, clip.src.y+y),
+        src->getRowStrideSize(clip.size.w));
+    }
+  }
+}
+
+void CopyRegion::onExecute()
+{
+  swap();
+}
+
+void CopyRegion::onUndo()
+{
+  swap();
+}
+
+void CopyRegion::onRedo()
+{
+  swap();
+}
+
+void CopyRegion::swap()
+{
+  Image* image = this->image();
+
+  // Save current image region in "tmp" stream
+  std::stringstream tmp;
+  for (const auto& rc : m_region)
+    for (int y=0; y<rc.h; ++y)
+      tmp.write(
+        (const char*)image->getPixelAddress(rc.x, rc.y+y),
+        image->getRowStrideSize(rc.w));
+
+  // Restore m_stream into the image
+  for (const auto& rc : m_region) {
+    for (int y=0; y<rc.h; ++y) {
+      m_stream.read(
+        (char*)image->getPixelAddress(rc.x, rc.y+y),
+        image->getRowStrideSize(rc.w));
+    }
+  }
+
+  std::swap(m_stream, tmp);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/copy_region.h

@@ -0,0 +1,58 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_COPY_REGION_H_INCLUDED
+#define APP_CMD_COPY_REGION_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_image.h"
+#include "gfx/region.h"
+
+#include <sstream>
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class CopyRegion : public Cmd
+                   , public WithImage {
+  public:
+    CopyRegion(Image* dst, Image* src,
+      const gfx::Region& region, int src_dx, int src_dy);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) +
+        const_cast<std::stringstream*>(&m_stream)->tellp();
+    }
+
+  private:
+    void swap();
+
+    gfx::Region m_region;
+    std::stringstream m_stream;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/deselect_mask.cpp

@@ -0,0 +1,60 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/deselect_mask.h"
+
+#include "app/cmd/set_mask.h"
+#include "app/document.h"
+#include "doc/mask.h"
+
+namespace app {
+namespace cmd {
+
+DeselectMask::DeselectMask(Document* doc)
+  : WithDocument(doc)
+{
+}
+
+void DeselectMask::onExecute()
+{
+  app::Document* doc = document();
+  m_oldMask.reset(doc->isMaskVisible() ? new Mask(*doc->mask()): nullptr);
+  doc->setMaskVisible(false);
+}
+
+void DeselectMask::onUndo()
+{
+  app::Document* doc = document();
+
+  doc->setMask(m_oldMask);
+  doc->setMaskVisible(true);
+
+  m_oldMask.reset(nullptr);
+}
+
+size_t DeselectMask::onMemSize() const
+{
+  return sizeof(*this) + (m_oldMask ? m_oldMask->getMemSize(): 0);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/deselect_mask.h

@@ -0,0 +1,52 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_DESELECT_MASK_H_INCLUDED
+#define APP_CMD_DESELECT_MASK_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_document.h"
+#include "base/unique_ptr.h"
+
+namespace doc {
+  class Mask;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class DeselectMask : public Cmd
+                     , public WithDocument {
+  public:
+    DeselectMask(Document* doc);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override;
+
+  private:
+    base::UniquePtr<Mask> m_oldMask;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/flatten_layers.cpp

@@ -0,0 +1,97 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/flatten_layers.h"
+
+#include "app/cmd/add_layer.h"
+#include "app/cmd/configure_background.h"
+#include "app/cmd/copy_rect.h"
+#include "app/cmd/remove_layer.h"
+#include "app/cmd/remove_layer.h"
+#include "app/document.h"
+#include "doc/cel.h"
+#include "doc/layer.h"
+#include "doc/primitives.h"
+#include "doc/sprite.h"
+#include "render/render.h"
+
+namespace app {
+namespace cmd {
+
+FlattenLayers::FlattenLayers(Sprite* sprite)
+  : WithSprite(sprite)
+{
+}
+
+void FlattenLayers::onExecute()
+{
+  Sprite* sprite = this->sprite();
+  app::Document* doc = static_cast<app::Document*>(sprite->document());
+
+  // Create a temporary image.
+  ImageRef image(Image::create(sprite->pixelFormat(),
+      sprite->width(),
+      sprite->height()));
+
+  // If there aren't a background layer we must to create the background.
+  LayerImage* background = sprite->backgroundLayer();
+  if (!background) {
+    background = new LayerImage(sprite);
+    executeAndAdd(new cmd::AddLayer(sprite->folder(), background, nullptr));
+    executeAndAdd(new cmd::ConfigureBackground(background));
+  }
+
+  render::Render render;
+  render.setBgType(render::BgType::NONE);
+  color_t bgcolor = doc->bgColor(background);
+
+  // Copy all frames to the background.
+  for (frame_t frame(0); frame<sprite->totalFrames(); ++frame) {
+    // Clear the image and render this frame.
+    clear_image(image, bgcolor);
+    render.renderSprite(image, sprite, frame);
+
+    ImageRef cel_image;
+    Cel* cel = background->cel(frame);
+    if (cel) {
+      cel_image = cel->imageRef();
+      ASSERT(cel_image);
+
+      executeAndAdd(new cmd::CopyRect(cel_image, image,
+          gfx::Clip(0, 0, image->bounds())));
+    }
+    else {
+      cel_image.reset(Image::createCopy(image));
+      cel = new Cel(frame, cel_image);
+      background->addCel(cel);
+    }
+  }
+
+  // Delete old layers.
+  LayerList layers = sprite->folder()->getLayersList();
+  for (Layer* layer : layers)
+    if (layer != background)
+      executeAndAdd(new cmd::RemoveLayer(layer));
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/flatten_layers.h

@@ -0,0 +1,42 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_FLATTEN_LAYERS_H_INCLUDED
+#define APP_CMD_FLATTEN_LAYERS_H_INCLUDED
+#pragma once
+
+#include "app/cmd/with_sprite.h"
+#include "app/cmd_sequence.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class FlattenLayers : public CmdSequence
+                      , public WithSprite {
+  public:
+    FlattenLayers(Sprite* sprite);
+
+  protected:
+    void onExecute() override;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/flip_image.cpp

@@ -0,0 +1,57 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/flip_image.h"
+
+#include "doc/image.h"
+#include "doc/algorithm/flip_image.h"
+
+namespace app {
+namespace cmd {
+
+FlipImage::FlipImage(Image* image, const gfx::Rect& bounds, doc::algorithm::FlipType flipType)
+  : WithImage(image)
+  , m_bounds(bounds)
+  , m_flipType(flipType)
+{
+}
+
+void FlipImage::onExecute()
+{
+  swap();
+}
+
+void FlipImage::onUndo()
+{
+  swap();
+}
+
+void FlipImage::swap()
+{
+  Image* image = this->image();
+
+  // Flip the portion of the bitmap.
+  doc::algorithm::flip_image(image, m_bounds, m_flipType);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/flip_image.h

@@ -0,0 +1,61 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_FLIP_IMAGE_H_INCLUDED
+#define APP_CMD_FLIP_IMAGE_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_image.h"
+#include "doc/algorithm/flip_type.h"
+#include "gfx/rect.h"
+
+#include <vector>
+
+namespace doc {
+  class Image;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class FlipImage : public Cmd
+                  , public WithImage {
+  public:
+    FlipImage(Image* image, const gfx::Rect& bounds,
+      doc::algorithm::FlipType flipType);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    void swap();
+
+    gfx::Rect m_bounds;
+    doc::algorithm::FlipType m_flipType;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/flip_mask.cpp

@@ -0,0 +1,66 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/flip_mask.h"
+
+#include "app/document.h"
+#include "doc/algorithm/flip_image.h"
+#include "doc/mask.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+FlipMask::FlipMask(Document* doc, doc::algorithm::FlipType flipType)
+  : WithDocument(doc)
+  , m_flipType(flipType)
+{
+}
+
+void FlipMask::onExecute()
+{
+  swap();
+}
+
+void FlipMask::onUndo()
+{
+  swap();
+}
+
+void FlipMask::swap()
+{
+  Document* document = this->document();
+  Mask* mask = document->mask();
+
+  ASSERT(mask->bitmap());
+  if (!mask->bitmap())
+    return;
+
+  mask->freeze();
+  doc::algorithm::flip_image(mask->bitmap(),
+    mask->bitmap()->bounds(), m_flipType);
+  mask->unfreeze();
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/flip_mask.h

@@ -0,0 +1,52 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_FLIP_MASK_H_INCLUDED
+#define APP_CMD_FLIP_MASK_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_document.h"
+#include "doc/algorithm/flip_type.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class FlipMask : public Cmd
+                 , public WithDocument {
+  public:
+    FlipMask(Document* doc, doc::algorithm::FlipType flipType);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    void swap();
+
+    doc::algorithm::FlipType m_flipType;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/flip_masked_cel.cpp

@@ -0,0 +1,70 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/flip_masked_cel.h"
+
+#include "app/document.h"
+#include "doc/algorithm/flip_image.h"
+#include "doc/cel.h"
+#include "doc/image.h"
+#include "doc/layer.h"
+#include "doc/mask.h"
+
+namespace app {
+namespace cmd {
+
+FlipMaskedCel::FlipMaskedCel(Cel* cel, doc::algorithm::FlipType flipType)
+  : WithCel(cel)
+  , m_flipType(flipType)
+  , m_bgcolor(static_cast<app::Document*>(cel->document())->bgColor(cel->layer()))
+{
+}
+
+void FlipMaskedCel::onExecute()
+{
+  swap();
+}
+
+void FlipMaskedCel::onUndo()
+{
+  swap();
+}
+
+void FlipMaskedCel::swap()
+{
+  Cel* cel = this->cel();
+  Image* image = cel->image();
+  Mask* mask = static_cast<app::Document*>(cel->document())->mask();
+  ASSERT(mask->bitmap());
+  if (!mask->bitmap())
+    return;
+
+  int x = cel->x();
+  int y = cel->y();
+
+  mask->offsetOrigin(-x, -y);
+  doc::algorithm::flip_image_with_mask(image, mask, m_flipType, m_bgcolor);
+  mask->offsetOrigin(x, y);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/flip_masked_cel.h

@@ -0,0 +1,54 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_FLIP_MASKED_CEL_H_INCLUDED
+#define APP_CMD_FLIP_MASKED_CEL_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+#include "doc/algorithm/flip_type.h"
+#include "doc/color.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class FlipMaskedCel : public Cmd
+                      , public WithCel {
+  public:
+    FlipMaskedCel(Cel* cel, doc::algorithm::FlipType flipType);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    void swap();
+
+    doc::algorithm::FlipType m_flipType;
+    color_t m_bgcolor;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/layer_from_background.cpp

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/layer_from_background.h"
+
+#include "app/cmd/set_layer_flags.h"
+#include "app/cmd/set_layer_name.h"
+#include "doc/layer.h"
+#include "doc/sprite.h"
+
+namespace app {
+namespace cmd {
+
+LayerFromBackground::LayerFromBackground(Layer* layer)
+{
+  ASSERT(layer != NULL);
+  ASSERT(layer->isVisible());
+  ASSERT(layer->isEditable());
+  ASSERT(layer->isBackground());
+  ASSERT(layer->sprite() != NULL);
+  ASSERT(layer->sprite()->backgroundLayer() != NULL);
+
+  // Remove "Background" and "LockMove" flags
+  LayerFlags newFlags = LayerFlags(int(layer->flags())
+    & ~int(LayerFlags::BackgroundLayerFlags));
+
+  add(new cmd::SetLayerFlags(layer, newFlags));
+  add(new cmd::SetLayerName(layer, "Layer 0"));
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/layer_from_background.h

@@ -0,0 +1,41 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_LAYER_FROM_BACKGROUND_H_INCLUDED
+#define APP_CMD_LAYER_FROM_BACKGROUND_H_INCLUDED
+#pragma once
+
+#include "app/cmd_sequence.h"
+
+namespace doc {
+  class Layer;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class LayerFromBackground : public CmdSequence {
+  public:
+    LayerFromBackground(Layer* layer);
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/move_cel.cpp

@@ -0,0 +1,146 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/move_cel.h"
+
+#include "app/cmd/add_cel.h"
+#include "app/cmd/add_frame.h"
+#include "app/cmd/clear_cel.h"
+#include "app/cmd/clear_image.h"
+#include "app/cmd/copy_rect.h"
+#include "app/cmd/remove_cel.h"
+#include "app/cmd/set_cel_frame.h"
+#include "app/document.h"
+#include "doc/cel.h"
+#include "doc/layer.h"
+#include "doc/primitives.h"
+#include "doc/sprite.h"
+#include "render/render.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+MoveCel::MoveCel(
+  LayerImage* srcLayer, frame_t srcFrame,
+  LayerImage* dstLayer, frame_t dstFrame)
+  : m_srcLayer(srcLayer)
+  , m_dstLayer(dstLayer)
+  , m_srcFrame(srcFrame)
+  , m_dstFrame(dstFrame)
+{
+}
+
+void MoveCel::onExecute()
+{
+  LayerImage* srcLayer = static_cast<LayerImage*>(m_srcLayer.layer());
+  LayerImage* dstLayer = static_cast<LayerImage*>(m_dstLayer.layer());
+
+  ASSERT(srcLayer);
+  ASSERT(dstLayer);
+
+  Sprite* srcSprite = srcLayer->sprite();
+  Sprite* dstSprite = dstLayer->sprite();
+  ASSERT(srcSprite);
+  ASSERT(dstSprite);
+  ASSERT(m_srcFrame >= 0 && m_srcFrame < srcSprite->totalFrames());
+  ASSERT(m_dstFrame >= 0);
+  (void)srcSprite;              // To avoid unused variable warning on Release mode
+
+  Cel* srcCel = srcLayer->cel(m_srcFrame);
+  Cel* dstCel = dstLayer->cel(m_dstFrame);
+
+  // Clear destination cel if it does exist. It'll be overriden by the
+  // copy of srcCel.
+  if (dstCel)
+    executeAndAdd(new cmd::ClearCel(dstCel));
+
+  // Add empty frames until newFrame
+  while (dstSprite->totalFrames() <= m_dstFrame)
+    executeAndAdd(new cmd::AddFrame(dstSprite, dstSprite->totalFrames()));
+
+  Image* srcImage = (srcCel ? srcCel->image(): NULL);
+  ImageRef dstImage;
+  dstCel = dstLayer->cel(m_dstFrame);
+  if (dstCel)
+    dstImage = dstCel->imageRef();
+
+  if (srcCel) {
+    if (srcLayer == dstLayer) {
+      if (dstLayer->isBackground()) {
+        ASSERT(dstImage);
+        if (dstImage) {
+          int blend = (srcLayer->isBackground() ?
+            BLEND_MODE_COPY: BLEND_MODE_NORMAL);
+
+          ImageRef tmp(Image::createCopy(dstImage));
+          render::composite_image(tmp, srcImage,
+            srcCel->x(), srcCel->y(), 255, blend);
+          executeAndAdd(new cmd::CopyRect(dstImage, tmp, gfx::Clip(tmp->bounds())));
+        }
+
+        executeAndAdd(new cmd::ClearImage(srcImage,
+            static_cast<app::Document*>(srcSprite->document())
+            ->bgColor(srcLayer)));
+      }
+      // Move the cel in the same layer.
+      else {
+        executeAndAdd(new cmd::SetCelFrame(srcCel, m_dstFrame));
+      }
+    }
+    // Move the cel between different layers.
+    else {
+      if (!dstCel) {
+        dstImage.reset(Image::createCopy(srcImage));
+
+        dstCel = new Cel(*srcCel);
+        dstCel->setFrame(m_dstFrame);
+        dstCel->setImage(dstImage);
+      }
+
+      if (dstLayer->isBackground()) {
+        ImageRef tmp(Image::createCopy(dstImage));
+        render::composite_image(tmp, srcImage,
+          srcCel->x(), srcCel->y(), 255, BLEND_MODE_NORMAL);
+        executeAndAdd(new cmd::CopyRect(dstImage, tmp, gfx::Clip(tmp->bounds())));
+      }
+      else {
+        executeAndAdd(new cmd::AddCel(dstLayer, dstCel));
+      }
+
+      executeAndAdd(new cmd::ClearCel(srcCel));
+    }
+  }
+}
+
+void MoveCel::onFireNotifications()
+{
+  CmdSequence::onFireNotifications();
+  static_cast<app::Document*>(m_dstLayer.layer()->sprite()->document())
+    ->notifyCelMoved(
+      m_srcLayer.layer(), m_srcFrame,
+      m_dstLayer.layer(), m_dstFrame);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/move_cel.h

@@ -0,0 +1,54 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_MOVE_CEL_H_INCLUDED
+#define APP_CMD_MOVE_CEL_H_INCLUDED
+#pragma once
+
+#include "app/cmd/with_layer.h"
+#include "app/cmd_sequence.h"
+#include "doc/color.h"
+#include "doc/frame.h"
+
+namespace doc {
+  class LayerImage;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class MoveCel : public CmdSequence {
+  public:
+    MoveCel(
+      LayerImage* srcLayer, frame_t srcFrame,
+      LayerImage* dstLayer, frame_t dstFrame);
+
+  protected:
+    void onExecute() override;
+    void onFireNotifications() override;
+
+  private:
+    WithLayer m_srcLayer, m_dstLayer;
+    frame_t m_srcFrame, m_dstFrame;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/move_layer.cpp

@@ -0,0 +1,67 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/move_layer.h"
+
+#include "doc/document.h"
+#include "doc/document_event.h"
+#include "doc/layer.h"
+#include "doc/sprite.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+MoveLayer::MoveLayer(Layer* layer, Layer* afterThis)
+  : m_layer(layer)
+  , m_oldAfterThis(layer->getPrevious())
+  , m_newAfterThis(afterThis)
+{
+}
+
+void MoveLayer::onExecute()
+{
+  m_layer.layer()->parent()->stackLayer(
+    m_layer.layer(),
+    m_newAfterThis.layer());
+}
+
+void MoveLayer::onUndo()
+{
+  m_layer.layer()->parent()->stackLayer(
+    m_layer.layer(),
+    m_oldAfterThis.layer());
+}
+
+void MoveLayer::onFireNotifications()
+{
+  Layer* layer = m_layer.layer();
+  doc::Document* doc = layer->sprite()->document();
+  DocumentEvent ev(doc);
+  ev.sprite(layer->sprite());
+  ev.layer(layer);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onLayerRestacked, ev);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/move_layer.h

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_MOVE_LAYER_H_INCLUDED
+#define APP_CMD_MOVE_LAYER_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_layer.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class MoveLayer : public Cmd {
+  public:
+    MoveLayer(Layer* layer, Layer* afterThis);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const {
+      return sizeof(*this);
+    }
+
+  private:
+    WithLayer m_layer;
+    WithLayer m_oldAfterThis;
+    WithLayer m_newAfterThis;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/object_io.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,7 +20,7 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/object_io.h"
+#include "app/cmd/object_io.h"
 
 #include "doc/cel.h"
 #include "doc/cel_io.h"
@@ -30,13 +30,12 @@
 #include "doc/layer_io.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
+using namespace doc;
 
-ObjectIO::ObjectIO(ObjectsContainer* objects, Sprite* sprite)
-  : m_objects(objects)
-  , m_sprite(sprite)
+ObjectIO::ObjectIO(Sprite* sprite)
+  : m_sprite(sprite)
 {
 }
 
@@ -82,5 +81,5 @@ Layer* ObjectIO::read_layer(std::istream& is)
     });
 }
 
-} // namespace undoers
+} // namespace cmd
 } // namespace app

src/app/cmd/object_io.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,14 +16,13 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_OBJECT_IO_H_INCLUDED
-#define APP_UNDOERS_OBJECT_IO_H_INCLUDED
+#ifndef APP_CMD_OBJECT_IO_H_INCLUDED
+#define APP_CMD_OBJECT_IO_H_INCLUDED
 #pragma once
 
 #include "base/serialization.h"
 #include "base/unique_ptr.h"
 #include "doc/subobjects_io.h"
-#include "undo/objects_container.h"
 
 namespace doc {
   class Cel;
@@ -33,13 +32,12 @@ namespace doc {
 }
 
 namespace app {
-namespace undoers {
+namespace cmd {
   using namespace doc;
-  using namespace undo;
 
   class ObjectIO : public SubObjectsIO {
   public:
-    ObjectIO(ObjectsContainer* objects, Sprite* sprite);
+    ObjectIO(Sprite* sprite);
     virtual ~ObjectIO();
 
     // How to write cels, images, and sub-layers
@@ -66,15 +64,8 @@ namespace undoers {
     {
       using base::serialization::little_endian::write32;
 
-      // Get an ID for the image.
-      undo::ObjectId objectId = m_objects->addObject(object);
-
-      write32(os, objectId);        // Write the ID
-      writer(os, object);           // Write the object
-
-      // Remove the object from the container (it will be
-      // re-added by a undoers::read_object call).
-      m_objects->removeObject(objectId);
+      write32(os, object->id()); // Write the ID
+      writer(os, object);        // Write the object
     }
 
     // Deserializes the given object from the stream, adding the object
@@ -84,19 +75,17 @@ namespace undoers {
     {
       using base::serialization::little_endian::read32;
 
-      undo::ObjectId objectId = read32(is);    // Read the ID
-      base::UniquePtr<T> object(reader(is));   // Read the object
+      doc::ObjectId objectId = read32(is);    // Read the ID
+      base::UniquePtr<T> object(reader(is));  // Read the object
 
-      // Re-insert the object in the container with the read ID.
-      m_objects->insertObject(objectId, object);
+      object->setId(objectId);
       return object.release();
     }
 
-    ObjectsContainer* m_objects;
     Sprite* m_sprite;
   };
 
-} // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_OBJECT_IO_H_INCLUDED
+#endif

src/app/cmd/remove_cel.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,37 +20,35 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_cel_opacity.h"
+#include "app/cmd/remove_cel.h"
 
 #include "doc/cel.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
+#include "doc/layer.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
+using namespace doc;
 
-SetCelOpacity::SetCelOpacity(ObjectsContainer* objects, Cel* cel)
-  : m_celId(objects->addObject(cel))
-  , m_opacity(cel->opacity())
+RemoveCel::RemoveCel(Cel* cel)
+  : AddCel(cel->layer(), cel)
 {
 }
 
-void SetCelOpacity::dispose()
+void RemoveCel::onExecute()
 {
-  delete this;
+  AddCel::onUndo();
 }
 
-void SetCelOpacity::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void RemoveCel::onUndo()
 {
-  Cel* cel = objects->getObjectT<Cel>(m_celId);
-
-  // Push another SetCelOpacity as redoer
-  redoers->pushUndoer(new SetCelOpacity(objects, cel));
-
-  cel->setOpacity(m_opacity);
+  AddCel::onRedo();
 }
 
-} // namespace undoers
+void RemoveCel::onRedo()
+{
+  AddCel::onUndo();
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/remove_cel.h

@@ -0,0 +1,42 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_REMOVE_CEL_H_INCLUDED
+#define APP_CMD_REMOVE_CEL_H_INCLUDED
+#pragma once
+
+#include "app/cmd/add_cel.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class RemoveCel : public AddCel {
+  public:
+    RemoveCel(Cel* cel);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/remove_frame.cpp

@@ -0,0 +1,81 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/remove_frame.h"
+
+#include "app/cmd/remove_cel.h"
+#include "doc/document.h"
+#include "doc/document_event.h"
+#include "doc/sprite.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+RemoveFrame::RemoveFrame(Sprite* sprite, frame_t frame)
+  : WithSprite(sprite)
+  , m_frame(frame)
+  , m_firstTime(true)
+{
+  for (Cel* cel : sprite->cels(m_frame))
+    m_seq.add(new cmd::RemoveCel(cel));
+}
+
+void RemoveFrame::onExecute()
+{
+  Sprite* sprite = this->sprite();
+  Document* doc = sprite->document();
+
+  if (m_firstTime) {
+    m_firstTime = false;
+    m_seq.execute(context());
+  }
+  else
+    m_seq.redo();
+
+  sprite->removeFrame(m_frame);
+
+  // Notify observers.
+  DocumentEvent ev(doc);
+  ev.sprite(sprite);
+  ev.frame(m_frame);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onRemoveFrame, ev);
+}
+
+void RemoveFrame::onUndo()
+{
+  Sprite* sprite = this->sprite();
+  Document* doc = sprite->document();
+
+  sprite->addFrame(m_frame);
+  m_seq.undo();
+
+  // Notify observers about the new frame.
+  DocumentEvent ev(doc);
+  ev.sprite(sprite);
+  ev.frame(m_frame);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onAddFrame, ev);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/remove_frame.h

@@ -0,0 +1,53 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_REMOVE_FRAME_H_INCLUDED
+#define APP_CMD_REMOVE_FRAME_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_sprite.h"
+#include "app/cmd_sequence.h"
+#include "doc/frame.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class RemoveFrame : public Cmd
+                    , public WithSprite {
+  public:
+    RemoveFrame(Sprite* sprite, frame_t frame);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) + m_seq.memSize();
+    }
+
+  private:
+    frame_t m_frame;
+    CmdSequence m_seq;
+    bool m_firstTime;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/remove_layer.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,37 +20,35 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_layer_name.h"
+#include "app/cmd/remove_layer.h"
 
 #include "doc/layer.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
+#include "doc/layer.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
+using namespace doc;
 
-SetLayerName::SetLayerName(ObjectsContainer* objects, Layer* layer)
-  : m_layerId(objects->addObject(layer))
-  , m_name(layer->name())
+RemoveLayer::RemoveLayer(Layer* layer)
+  : AddLayer(layer->parent(), layer, layer->getPrevious())
 {
 }
 
-void SetLayerName::dispose()
+void RemoveLayer::onExecute()
 {
-  delete this;
+  AddLayer::onUndo();
 }
 
-void SetLayerName::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void RemoveLayer::onUndo()
 {
-  Layer* layer = objects->getObjectT<Layer>(m_layerId);
-
-  // Push another SetLayerName as redoer
-  redoers->pushUndoer(new SetLayerName(objects, layer));
-
-  layer->setName(m_name.c_str());
+  AddLayer::onRedo();
 }
 
-} // namespace undoers
+void RemoveLayer::onRedo()
+{
+  AddLayer::onUndo();
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/remove_layer.h

@@ -0,0 +1,42 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_REMOVE_LAYER_H_INCLUDED
+#define APP_CMD_REMOVE_LAYER_H_INCLUDED
+#pragma once
+
+#include "app/cmd/add_layer.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class RemoveLayer : public AddLayer {
+  public:
+    RemoveLayer(Layer* layer);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/remove_palette.cpp

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/remove_palette.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+RemovePalette::RemovePalette(Sprite* sprite, Palette* pal)
+  : AddPalette(sprite, pal)
+{
+}
+
+void RemovePalette::onExecute()
+{
+  AddPalette::onUndo();
+}
+
+void RemovePalette::onUndo()
+{
+  AddPalette::onRedo();
+}
+
+void RemovePalette::onRedo()
+{
+  AddPalette::onUndo();
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/remove_palette.h

@@ -0,0 +1,42 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_REMOVE_PALETTE_H_INCLUDED
+#define APP_CMD_REMOVE_PALETTE_H_INCLUDED
+#pragma once
+
+#include "app/cmd/add_palette.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class RemovePalette : public AddPalette {
+  public:
+    RemovePalette(Sprite* sprite, Palette* pal);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/replace_image.cpp

@@ -0,0 +1,80 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/replace_image.h"
+
+#include "app/cmd/object_io.h"
+#include "doc/image.h"
+#include "doc/image_io.h"
+#include "doc/image_ref.h"
+#include "doc/sprite.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+ReplaceImage::ReplaceImage(Sprite* sprite, const ImageRef& oldImage, const ImageRef& newImage)
+  : WithSprite(sprite)
+  , m_oldImageId(oldImage->id())
+  , m_newImageId(newImage->id())
+  , m_newImage(newImage)
+{
+}
+
+void ReplaceImage::onExecute()
+{
+  // Save old image in m_copy. We cannot keep an ImageRef to this
+  // image, because there are other undo branches that could try to
+  // modify/re-add this same image ID
+  ImageRef oldImage = sprite()->getImage(m_oldImageId);
+  ASSERT(oldImage);
+  m_copy.reset(Image::createCopy(oldImage));
+
+  sprite()->replaceImage(m_oldImageId, m_newImage);
+  m_newImage.reset(nullptr);
+}
+
+void ReplaceImage::onUndo()
+{
+  ImageRef newImage = sprite()->getImage(m_newImageId);
+  ASSERT(newImage);
+  ASSERT(!sprite()->getImage(m_oldImageId));
+  m_copy->setId(m_oldImageId);
+
+  sprite()->replaceImage(m_newImageId, m_copy);
+  m_copy.reset(Image::createCopy(newImage));
+}
+
+void ReplaceImage::onRedo()
+{
+  ImageRef oldImage = sprite()->getImage(m_oldImageId);
+  ASSERT(oldImage);
+  ASSERT(!sprite()->getImage(m_newImageId));
+  m_copy->setId(m_newImageId);
+
+  sprite()->replaceImage(m_oldImageId, m_copy);
+  m_copy.reset(Image::createCopy(oldImage));
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/replace_image.h

@@ -0,0 +1,62 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_REPLACE_IMAGE_H_INCLUDED
+#define APP_CMD_REPLACE_IMAGE_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_sprite.h"
+// #include "app/cmd/with_image.h"
+#include "doc/image_ref.h"
+
+#include <sstream>
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class ReplaceImage : public Cmd
+                     , public WithSprite {
+  public:
+    ReplaceImage(Sprite* sprite, const ImageRef& oldImage, const ImageRef& newImage);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) +
+        (m_copy ? m_copy->getMemSize(): 0);
+    }
+
+  private:
+    // Reference used only to keep the copy of the new image from the
+    // ReplaceImage() ctor until the ReplaceImage::onExecute() call.
+    // Then the reference is not used anymore.
+    ImageRef m_newImage;
+
+    ObjectId m_oldImageId;
+    ObjectId m_newImageId;
+    ImageRef m_copy;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/reselect_mask.cpp

@@ -0,0 +1,64 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/reselect_mask.h"
+
+#include "app/cmd/set_mask.h"
+#include "app/document.h"
+#include "doc/mask.h"
+
+namespace app {
+namespace cmd {
+
+ReselectMask::ReselectMask(Document* doc)
+  : WithDocument(doc)
+{
+}
+
+void ReselectMask::onExecute()
+{
+  app::Document* doc = document();
+
+  if (m_oldMask) {
+    doc->setMask(m_oldMask);
+    m_oldMask.reset(nullptr);
+  }
+
+  doc->setMaskVisible(true);
+}
+
+void ReselectMask::onUndo()
+{
+  app::Document* doc = document();
+
+  m_oldMask.reset(doc->isMaskVisible() ? new Mask(*doc->mask()): nullptr);
+
+  doc->setMaskVisible(false);
+}
+
+size_t ReselectMask::onMemSize() const
+{
+  return sizeof(*this) + (m_oldMask ? m_oldMask->getMemSize(): 0);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/reselect_mask.h

@@ -0,0 +1,52 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_RESELECT_MASK_H_INCLUDED
+#define APP_CMD_RESELECT_MASK_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_document.h"
+#include "base/unique_ptr.h"
+
+namespace doc {
+  class Mask;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class ReselectMask : public Cmd
+                     , public WithDocument {
+  public:
+    ReselectMask(Document* doc);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override;
+
+  private:
+    base::UniquePtr<Mask> m_oldMask;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_cel_frame.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,41 +20,49 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/remove_cel.h"
+#include "app/cmd/set_cel_frame.h"
 
-#include "app/undoers/add_cel.h"
-#include "app/undoers/object_io.h"
 #include "doc/cel.h"
+#include "doc/document.h"
+#include "doc/document_event.h"
 #include "doc/layer.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
+#include "doc/sprite.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
 using namespace doc;
-using namespace undo;
 
-RemoveCel::RemoveCel(ObjectsContainer* objects, Layer* layer, Cel* cel)
-  : m_layerId(objects->addObject(layer))
+SetCelFrame::SetCelFrame(Cel* cel, frame_t frame)
+  : WithCel(cel)
+  , m_oldFrame(cel->frame())
+  , m_newFrame(frame)
 {
-  ObjectIO(objects, layer->sprite()).write_cel(m_stream, cel);
 }
 
-void RemoveCel::dispose()
+void SetCelFrame::onExecute()
 {
-  delete this;
+  Cel* cel = this->cel();
+  cel->layer()->moveCel(cel, m_newFrame);
 }
 
-void RemoveCel::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void SetCelFrame::onUndo()
 {
-  LayerImage* layer = objects->getObjectT<LayerImage>(m_layerId);
-  Cel* cel = ObjectIO(objects, layer->sprite()).read_cel(m_stream);
-
-  redoers->pushUndoer(new AddCel(objects, layer, cel));
-
-  layer->addCel(cel);
+  Cel* cel = this->cel();
+  cel->layer()->moveCel(cel, m_oldFrame);
 }
 
-} // namespace undoers
+void SetCelFrame::onFireNotifications()
+{
+  Cel* cel = this->cel();
+  doc::Document* doc = cel->sprite()->document();
+  DocumentEvent ev(doc);
+  ev.sprite(cel->layer()->sprite());
+  ev.layer(cel->layer());
+  ev.cel(cel);
+  ev.frame(cel->frame());
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onCelFrameChanged, ev);
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/set_cel_frame.h

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_CEL_FRAME_H_INCLUDED
+#define APP_CMD_SET_CEL_FRAME_CEL_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetCelFrame : public Cmd
+                    , public WithCel {
+  public:
+    SetCelFrame(Cel* cel, frame_t frame);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const {
+      return sizeof(*this);
+    }
+
+  private:
+    frame_t m_oldFrame;
+    frame_t m_newFrame;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_cel_opacity.cpp

@@ -0,0 +1,61 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/set_cel_opacity.h"
+
+#include "app/document.h"
+#include "doc/cel.h"
+#include "doc/document_event.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+SetCelOpacity::SetCelOpacity(Cel* cel, int opacity)
+  : WithCel(cel)
+  , m_oldOpacity(cel->opacity())
+  , m_newOpacity(opacity)
+{
+}
+
+void SetCelOpacity::onExecute()
+{
+  cel()->setOpacity(m_newOpacity);
+}
+
+void SetCelOpacity::onUndo()
+{
+  cel()->setOpacity(m_oldOpacity);
+}
+
+void SetCelOpacity::onFireNotifications()
+{
+  Cel* cel = this->cel();
+  DocumentEvent ev(cel->document());
+  ev.sprite(cel->sprite());
+  ev.cel(cel);
+  cel->document()->notifyObservers<DocumentEvent&>(&DocumentObserver::onCelOpacityChanged, ev);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/set_cel_opacity.h

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_CEL_OPACITY_H_INCLUDED
+#define APP_CMD_SET_CEL_OPACITY_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetCelOpacity : public Cmd
+                      , public WithCel {
+  public:
+    SetCelOpacity(Cel* cel, int opacity);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    int m_oldOpacity;
+    int m_newOpacity;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_cel_position.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,38 +20,44 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/add_layer.h"
+#include "app/cmd/set_cel_position.h"
 
 #include "app/document.h"
-#include "app/document_api.h"
-#include "app/undoers/remove_layer.h"
-#include "doc/layer.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
+#include "doc/cel.h"
+#include "doc/document_event.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
+using namespace doc;
 
-AddLayer::AddLayer(ObjectsContainer* objects, Document* document, Layer* layer)
-  : m_documentId(objects->addObject(document))
-  , m_layerId(objects->addObject(layer))
+SetCelPosition::SetCelPosition(Cel* cel, int x, int y)
+  : WithCel(cel)
+  , m_oldX(cel->x())
+  , m_oldY(cel->y())
+  , m_newX(x)
+  , m_newY(y)
 {
 }
 
-void AddLayer::dispose()
+void SetCelPosition::onExecute()
 {
-  delete this;
+  cel()->setPosition(m_newX, m_newY);
 }
 
-void AddLayer::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void SetCelPosition::onUndo()
 {
-  Document* document = objects->getObjectT<Document>(m_documentId);
-  Layer* layer = objects->getObjectT<Layer>(m_layerId);
-
-  document->getApi(redoers).removeLayer(layer);
+  cel()->setPosition(m_oldX, m_oldY);
 }
 
-} // namespace undoers  
+void SetCelPosition::onFireNotifications()
+{
+  Cel* cel = this->cel();
+  DocumentEvent ev(cel->document());
+  ev.sprite(cel->sprite());
+  ev.cel(cel);
+  cel->document()->notifyObservers<DocumentEvent&>(&DocumentObserver::onCelPositionChanged, ev);
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/set_cel_position.h

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_CEL_POSITION_H_INCLUDED
+#define APP_CMD_SET_CEL_POSITION_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetCelPosition : public Cmd
+                       , public WithCel {
+  public:
+    SetCelPosition(Cel* cel, int x, int y);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    int m_oldX, m_oldY;
+    int m_newX, m_newY;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_frame_duration.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,40 +20,42 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_frame_duration.h"
+#include "app/cmd/set_frame_duration.h"
 
+#include "app/document.h"
+#include "doc/document_event.h"
 #include "doc/sprite.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
-
-SetFrameDuration::SetFrameDuration(ObjectsContainer* objects, Sprite* sprite, frame_t frame)
-  : m_spriteId(objects->addObject(sprite))
+SetFrameDuration::SetFrameDuration(Sprite* sprite, frame_t frame, int duration)
+  : WithSprite(sprite)
   , m_frame(frame)
+  , m_oldDuration(sprite->frameDuration(frame))
+  , m_newDuration(duration)
 {
-  ASSERT(frame >= 0 && frame < sprite->totalFrames());
-
-  m_duration = sprite->frameDuration(frame);
 }
 
-void SetFrameDuration::dispose()
+void SetFrameDuration::onExecute()
 {
-  delete this;
+  sprite()->setFrameDuration(m_frame, m_newDuration);
 }
 
-void SetFrameDuration::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void SetFrameDuration::onUndo()
 {
-  Sprite* sprite = objects->getObjectT<Sprite>(m_spriteId);
-
-  // Push another SetFrameDuration as redoer
-  redoers->pushUndoer(new SetFrameDuration(objects, sprite, m_frame));
-
-  sprite->setFrameDuration(m_frame, m_duration);
+  sprite()->setFrameDuration(m_frame, m_oldDuration);
 }
 
-} // namespace undoers
+void SetFrameDuration::onFireNotifications()
+{
+  Sprite* sprite = this->sprite();
+  doc::Document* doc = sprite->document();
+  DocumentEvent ev(doc);
+  ev.sprite(sprite);
+  ev.frame(m_frame);
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onFrameDurationChanged, ev);
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/set_frame_duration.h

@@ -0,0 +1,53 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_FRAME_DURATION_H_INCLUDED
+#define APP_CMD_SET_FRAME_DURATION_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_sprite.h"
+#include "doc/frame.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetFrameDuration : public Cmd
+                         , public WithSprite {
+  public:
+    SetFrameDuration(Sprite* sprite, frame_t frame, int duration);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    frame_t m_frame;
+    int m_oldDuration;
+    int m_newDuration;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_layer_flags.cpp

@@ -0,0 +1,46 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/set_layer_flags.h"
+
+namespace app {
+namespace cmd {
+
+SetLayerFlags::SetLayerFlags(Layer* layer, LayerFlags flags)
+  : WithLayer(layer)
+  , m_oldFlags(layer->flags())
+  , m_newFlags(flags)
+{
+}
+
+void SetLayerFlags::onExecute()
+{
+  layer()->setFlags(m_newFlags);
+}
+
+void SetLayerFlags::onUndo()
+{
+  layer()->setFlags(m_oldFlags);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/set_layer_flags.h

@@ -0,0 +1,51 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_LAYER_FLAGS_H_INCLUDED
+#define APP_CMD_SET_LAYER_FLAGS_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_layer.h"
+#include "doc/layer.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetLayerFlags : public Cmd
+                     , public WithLayer {
+  public:
+    SetLayerFlags(Layer* layer, LayerFlags flags);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    LayerFlags m_oldFlags;
+    LayerFlags m_newFlags;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_layer_name.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,37 +20,29 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_layer_flags.h"
+#include "app/cmd/set_layer_name.h"
 
 #include "doc/layer.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
-
-SetLayerFlags::SetLayerFlags(ObjectsContainer* objects, Layer* layer)
-  : m_layerId(objects->addObject(layer))
-  , m_flags(uint32_t(layer->flags()))
+SetLayerName::SetLayerName(Layer* layer, const std::string& name)
+  : WithLayer(layer)
+  , m_oldName(layer->name())
+  , m_newName(name)
 {
 }
 
-void SetLayerFlags::dispose()
+void SetLayerName::onExecute()
 {
-  delete this;
+  layer()->setName(m_newName);
 }
 
-void SetLayerFlags::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void SetLayerName::onUndo()
 {
-  Layer* layer = objects->getObjectT<Layer>(m_layerId);
-
-  // Push another SetLayerFlags as redoer
-  redoers->pushUndoer(new SetLayerFlags(objects, layer));
-
-  layer->setFlags(LayerFlags(m_flags));
+  layer()->setName(m_oldName);
 }
 
-} // namespace undoers
+} // namespace cmd
 } // namespace app

src/app/cmd/set_layer_name.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,38 +16,37 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_SET_LAYER_FLAGS_H_INCLUDED
-#define APP_UNDOERS_SET_LAYER_FLAGS_H_INCLUDED
+#ifndef APP_CMD_SET_LAYER_NAME_H_INCLUDED
+#define APP_CMD_SET_LAYER_NAME_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
-#include "undo/object_id.h"
+#include "app/cmd.h"
+#include "app/cmd/with_layer.h"
 
 #include <string>
 
-namespace doc {
-  class Layer;
-}
-
 namespace app {
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+namespace cmd {
+  using namespace doc;
 
-    class SetLayerFlags : public UndoerBase {
-    public:
-      SetLayerFlags(ObjectsContainer* objects, Layer* layer);
+  class SetLayerName : public Cmd
+                     , public WithLayer {
+  public:
+    SetLayerName(Layer* layer, const std::string& name);
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
 
-    private:
-      undo::ObjectId m_layerId;
-      uint32_t m_flags;
-    };
+  private:
+    std::string m_oldName;
+    std::string m_newName;
+  };
 
-  } // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_SET_LAYER_FLAGS_H_INCLUDED
+#endif

src/app/cmd/set_mask.cpp

@@ -0,0 +1,77 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/set_mask.h"
+
+#include "app/document.h"
+#include "doc/mask.h"
+
+namespace app {
+namespace cmd {
+
+SetMask::SetMask(Document* doc, Mask* newMask)
+  : WithDocument(doc)
+  , m_oldMask(doc->isMaskVisible() ? new Mask(*doc->mask()): nullptr)
+  , m_newMask(newMask && !newMask->isEmpty() ? new Mask(*newMask): nullptr)
+{
+}
+
+void SetMask::setNewMask(Mask* newMask)
+{
+  m_newMask.reset(newMask ? new Mask(*newMask): nullptr);
+  setMask(m_newMask);
+}
+
+void SetMask::onExecute()
+{
+  setMask(m_newMask);
+}
+
+void SetMask::onUndo()
+{
+  setMask(m_oldMask);
+}
+
+size_t SetMask::onMemSize() const
+{
+  return sizeof(*this) +
+    (m_oldMask ? m_oldMask->getMemSize(): 0) +
+    (m_newMask ? m_newMask->getMemSize(): 0);
+}
+
+void SetMask::setMask(Mask* mask)
+{
+  app::Document* doc = document();
+
+  if (mask) {
+    doc->setMask(mask);
+    doc->setMaskVisible(!mask->isEmpty());
+  }
+  else {
+    Mask empty;
+    doc->setMask(&empty);
+    doc->setMaskVisible(false);
+  }
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/set_mask.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,35 +16,45 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_SET_MASK_POSITION_H_INCLUDED
-#define APP_UNDOERS_SET_MASK_POSITION_H_INCLUDED
+#ifndef APP_CMD_SET_MASK_H_INCLUDED
+#define APP_CMD_SET_MASK_H_INCLUDED
 #pragma once
 
-#include "undo/object_id.h"
-#include "app/undoers/undoer_base.h"
+#include "app/cmd.h"
+#include "app/cmd/with_document.h"
+#include "base/unique_ptr.h"
 
 #include <sstream>
 
+namespace doc {
+  class Mask;
+}
+
 namespace app {
-  class Document;
+namespace cmd {
+  using namespace doc;
 
-  namespace undoers {
-    using namespace undo;
+  class SetMask : public Cmd
+                , public WithDocument {
+  public:
+    SetMask(Document* doc, Mask* newMask);
 
-    class SetMaskPosition : public UndoerBase {
-    public:
-      SetMaskPosition(ObjectsContainer* objects, Document* document);
+    // Used to change the new mask used in the onRedo()
+    void setNewMask(Mask* newMask);
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override;
 
-    private:
-      undo::ObjectId m_documentId;
-      int m_x, m_y;
-    };
+  private:
+    void setMask(Mask* mask);
 
-  } // namespace undoers
+    base::UniquePtr<Mask> m_oldMask;
+    base::UniquePtr<Mask> m_newMask;
+  };
+
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_SET_MASK_POSITION_H_INCLUDED
+#endif

src/app/cmd/set_mask_position.cpp

@@ -0,0 +1,56 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/set_mask_position.h"
+
+#include "app/document.h"
+#include "doc/mask.h"
+
+namespace app {
+namespace cmd {
+
+SetMaskPosition::SetMaskPosition(Document* doc, const gfx::Point& pos)
+  : WithDocument(doc)
+  , m_oldPosition(doc->mask()->bounds().getOrigin())
+  , m_newPosition(pos)
+{
+}
+
+void SetMaskPosition::onExecute()
+{
+  setMaskPosition(m_newPosition);
+}
+
+void SetMaskPosition::onUndo()
+{
+  setMaskPosition(m_oldPosition);
+}
+
+void SetMaskPosition::setMaskPosition(const gfx::Point& pos)
+{
+  Document* doc = document();
+  doc->mask()->setOrigin(pos.x, pos.y);
+  doc->resetTransformation();
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/set_mask_position.h

@@ -0,0 +1,53 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_MASK_POSITION_H_INCLUDED
+#define APP_CMD_SET_MASK_POSITION_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_document.h"
+#include "gfx/point.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetMaskPosition : public Cmd
+                        , public WithDocument {
+  public:
+    SetMaskPosition(Document* doc, const gfx::Point& pos);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    void setMaskPosition(const gfx::Point& pos);
+
+    gfx::Point m_oldPosition;
+    gfx::Point m_newPosition;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_palette.cpp

@@ -0,0 +1,75 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/set_palette.h"
+
+#include "base/serialization.h"
+#include "doc/palette.h"
+#include "doc/sprite.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+SetPalette::SetPalette(Sprite* sprite, frame_t frame, Palette* newPalette)
+  : WithSprite(sprite)
+  , m_frame(frame)
+{
+  Palette* curPalette = sprite->palette(frame);
+
+  // Check differences between current sprite palette and the new one
+  m_from = m_to = -1;
+  curPalette->countDiff(newPalette, &m_from, &m_to);
+
+  if (m_from >= 0 && m_to >= m_from) {
+    size_t ncolors = m_to-m_from+1;
+    m_oldColors.resize(ncolors);
+    m_newColors.resize(ncolors);
+
+    for (size_t i=0; i<ncolors; ++i) {
+      m_oldColors[i] = curPalette->getEntry(m_from+i);
+      m_newColors[i] = newPalette->getEntry(m_from+i);
+    }
+  }
+}
+
+void SetPalette::onExecute()
+{
+  Sprite* sprite = this->sprite();
+  Palette* palette = sprite->palette(m_frame);
+
+  for (size_t i=0; i<m_newColors.size(); ++i)
+    palette->setEntry(m_from+i, m_newColors[i]);
+}
+
+void SetPalette::onUndo()
+{
+  Sprite* sprite = this->sprite();
+  Palette* palette = sprite->palette(m_frame);
+
+  for (size_t i=0; i<m_oldColors.size(); ++i)
+    palette->setEntry(m_from+i, m_oldColors[i]);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/set_palette.h

@@ -0,0 +1,63 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_PALETTE_COLORS_H_INCLUDED
+#define APP_CMD_SET_PALETTE_COLORS_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_sprite.h"
+#include "doc/color.h"
+#include "doc/frame.h"
+
+#include <vector>
+
+namespace doc {
+  class Palette;
+  class Sprite;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetPalette : public Cmd
+                   , public WithSprite {
+  public:
+    SetPalette(Sprite* sprite, frame_t frame, Palette* newPalette);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) +
+        sizeof(doc::color_t) * (m_oldColors.size() +
+                                m_newColors.size());
+    }
+
+  private:
+    frame_t m_frame;
+    int m_from, m_to;
+    std::vector<color_t> m_oldColors;
+    std::vector<color_t> m_newColors;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_pixel_format.cpp

@@ -0,0 +1,142 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/set_pixel_format.h"
+
+#include "app/cmd/add_palette.h"
+#include "app/cmd/remove_palette.h"
+#include "app/cmd/replace_image.h"
+#include "app/cmd/set_cel_opacity.h"
+#include "app/document.h"
+#include "base/unique_ptr.h"
+#include "doc/cel.h"
+#include "doc/document.h"
+#include "doc/layer.h"
+#include "doc/palette.h"
+#include "doc/sprite.h"
+#include "render/quantization.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+SetPixelFormat::SetPixelFormat(Sprite* sprite,
+  PixelFormat newFormat, DitheringMethod dithering)
+  : WithSprite(sprite)
+  , m_oldFormat(sprite->pixelFormat())
+  , m_newFormat(newFormat)
+  , m_dithering(dithering)
+{
+  if (sprite->pixelFormat() == newFormat)
+    return;
+
+  // TODO Review this, why we use the palette in frame 0?
+  frame_t frame(0);
+
+  // Use the rgbmap for the specified sprite
+  const RgbMap* rgbmap = sprite->rgbMap(frame);
+
+  // Get the list of cels from the background layer (if it
+  // exists). This list will be used to check if each image belong to
+  // the background layer.
+  CelList bgCels;
+  if (sprite->backgroundLayer() != NULL)
+    sprite->backgroundLayer()->getCels(bgCels);
+
+  std::vector<Image*> images;
+  sprite->getImages(images);
+  for (auto& old_image : images) {
+    bool is_image_from_background = false;
+    for (CelList::iterator it=bgCels.begin(), end=bgCels.end(); it != end; ++it) {
+      if ((*it)->image()->id() == old_image->id()) {
+        is_image_from_background = true;
+        break;
+      }
+    }
+
+    ImageRef new_image(render::convert_pixel_format
+      (old_image, NULL, newFormat, m_dithering, rgbmap,
+        sprite->palette(frame),
+        is_image_from_background));
+
+    m_seq.add(new cmd::ReplaceImage(sprite,
+        sprite->getImage(old_image->id()), new_image));
+  }
+
+  // Set all cels opacity to 100% if we are converting to indexed.
+  if (newFormat == IMAGE_INDEXED) {
+    CelList cels;
+    sprite->getCels(cels);
+    for (auto it = cels.begin(), end = cels.end(); it != end; ++it) {
+      Cel* cel = *it;
+      if (cel->opacity() < 255)
+        m_seq.add(new cmd::SetCelOpacity(cel, 255));
+    }
+  }
+
+  // When we are converting to grayscale color mode, we've to destroy
+  // all palettes and put only one grayscaled-palette at the first
+  // frame.
+  if (newFormat == IMAGE_GRAYSCALE) {
+    // Add undoers to revert all palette changes.
+    PalettesList palettes = sprite->getPalettes();
+    for (Palette* pal : palettes)
+      m_seq.add(new cmd::RemovePalette(sprite, pal));
+
+    base::UniquePtr<Palette> graypal(Palette::createGrayscale());
+    graypal->setFrame(0);
+    m_seq.add(new cmd::AddPalette(sprite, graypal));
+  }
+}
+
+void SetPixelFormat::onExecute()
+{
+  m_seq.execute(context());
+  setFormat(m_newFormat);
+}
+
+void SetPixelFormat::onUndo()
+{
+  m_seq.undo();
+  setFormat(m_oldFormat);
+}
+
+void SetPixelFormat::onRedo()
+{
+  m_seq.redo();
+  setFormat(m_newFormat);
+}
+
+void SetPixelFormat::setFormat(PixelFormat format)
+{
+  Sprite* sprite = this->sprite();
+
+  sprite->setPixelFormat(format);
+
+  // Regenerate extras
+  static_cast<app::Document*>(sprite->document())
+    ->destroyExtraCel();
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/set_pixel_format.h

@@ -0,0 +1,63 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_PIXEL_FORMAT_H_INCLUDED
+#define APP_CMD_SET_PIXEL_FORMAT_H_INCLUDED
+#pragma once
+
+#include "app/cmd_sequence.h"
+#include "app/cmd/with_sprite.h"
+#include "doc/pixel_format.h"
+#include "doc/dithering_method.h"
+
+namespace doc {
+  class Sprite;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetPixelFormat : public Cmd
+                       , public WithSprite {
+  public:
+    SetPixelFormat(Sprite* sprite,
+      PixelFormat newFormat,
+      DitheringMethod dithering);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onRedo() override;
+    size_t onMemSize() const override {
+      return sizeof(*this) + m_seq.memSize();
+    }
+
+  private:
+    void setFormat(PixelFormat format);
+
+    PixelFormat m_oldFormat;
+    PixelFormat m_newFormat;
+    DitheringMethod m_dithering;
+    CmdSequence m_seq;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_sprite_size.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,40 +20,43 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_mask_position.h"
+#include "app/cmd/set_sprite_size.h"
 
 #include "app/document.h"
-#include "doc/mask.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
+#include "doc/document_event.h"
+#include "doc/sprite.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
-
-SetMaskPosition::SetMaskPosition(ObjectsContainer* objects, Document* document)
-  : m_documentId(objects->addObject(document))
-  , m_x(document->mask()->bounds().x)
-  , m_y(document->mask()->bounds().y)
+SetSpriteSize::SetSpriteSize(Sprite* sprite, int newWidth, int newHeight)
+  : WithSprite(sprite)
+  , m_oldWidth(sprite->width())
+  , m_oldHeight(sprite->height())
+  , m_newWidth(newWidth)
+  , m_newHeight(newHeight)
 {
+  ASSERT(m_newWidth > 0);
+  ASSERT(m_newHeight > 0);
 }
 
-void SetMaskPosition::dispose()
+void SetSpriteSize::onExecute()
 {
-  delete this;
+  sprite()->setSize(m_newWidth, m_newHeight);
 }
 
-void SetMaskPosition::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void SetSpriteSize::onUndo()
 {
-  Document* document = objects->getObjectT<Document>(m_documentId);
-
-  // Push another SetMaskPosition as redoer
-  redoers->pushUndoer(new SetMaskPosition(objects, document));
-
-  document->mask()->setOrigin(m_x, m_y);
-  document->resetTransformation();
+  sprite()->setSize(m_oldWidth, m_oldHeight);
 }
 
-} // namespace undoers
+void SetSpriteSize::onFireNotifications()
+{
+  Sprite* sprite = this->sprite();
+  DocumentEvent ev(sprite->document());
+  ev.sprite(sprite);
+  sprite->document()->notifyObservers<DocumentEvent&>(&DocumentObserver::onSpriteSizeChanged, ev);
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/set_sprite_size.h

@@ -0,0 +1,53 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_SPRITE_SIZE_H_INCLUDED
+#define APP_CMD_SET_SPRITE_SIZE_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_sprite.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetSpriteSize : public Cmd
+                      , public WithSprite {
+  public:
+    SetSpriteSize(Sprite* sprite, int newWidth, int newHeight);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    uint32_t m_oldWidth;
+    uint32_t m_oldHeight;
+    uint32_t m_newWidth;
+    uint32_t m_newHeight;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_total_frames.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,37 +20,41 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_sprite_pixel_format.h"
+#include "app/cmd/set_total_frames.h"
 
+#include "app/document.h"
+#include "doc/document_event.h"
 #include "doc/sprite.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
-
-SetSpritePixelFormat::SetSpritePixelFormat(ObjectsContainer* objects, Sprite* sprite)
-  : m_spriteId(objects->addObject(sprite))
-  , m_format(sprite->pixelFormat())
+SetTotalFrames::SetTotalFrames(Sprite* sprite, frame_t frames)
+  : WithSprite(sprite)
+  , m_oldFrames(sprite->totalFrames())
+  , m_newFrames(frames)
 {
 }
 
-void SetSpritePixelFormat::dispose()
+void SetTotalFrames::onExecute()
 {
-  delete this;
+  sprite()->setTotalFrames(m_newFrames);
 }
 
-void SetSpritePixelFormat::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void SetTotalFrames::onUndo()
 {
-  Sprite* sprite = objects->getObjectT<Sprite>(m_spriteId);
-
-  // Push another SetSpritePixelFormat as redoer
-  redoers->pushUndoer(new SetSpritePixelFormat(objects, sprite));
-
-  sprite->setPixelFormat(static_cast<PixelFormat>(m_format));
+  sprite()->setTotalFrames(m_oldFrames);
 }
 
-} // namespace undoers
+void SetTotalFrames::onFireNotifications()
+{
+  Sprite* sprite = this->sprite();
+  doc::Document* doc = sprite->document();
+  DocumentEvent ev(doc);
+  ev.sprite(sprite);
+  ev.frame(sprite->totalFrames());
+  doc->notifyObservers<DocumentEvent&>(&DocumentObserver::onTotalFramesChanged, ev);
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/set_total_frames.h

@@ -0,0 +1,52 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_TOTAL_FRAMES_H_INCLUDED
+#define APP_CMD_SET_TOTAL_FRAMES_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_sprite.h"
+#include "doc/frame.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetTotalFrames : public Cmd
+                       , public WithSprite {
+  public:
+    SetTotalFrames(Sprite* sprite, frame_t frames);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    frame_t m_oldFrames;
+    frame_t m_newFrames;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/set_transparent_color.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,38 +20,39 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_total_frames.h"
+#include "app/cmd/set_transparent_color.h"
 
 #include "app/document.h"
-#include "app/document_api.h"
+#include "doc/document_event.h"
 #include "doc/sprite.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
-
-SetTotalFrames::SetTotalFrames(ObjectsContainer* objects, Document* document, Sprite* sprite)
-  : m_documentId(objects->addObject(document))
-  , m_spriteId(objects->addObject(sprite))
-  , m_totalFrames(sprite->totalFrames())
+SetTransparentColor::SetTransparentColor(Sprite* sprite, color_t newMask)
+  : WithSprite(sprite)
+  , m_oldMaskColor(sprite->transparentColor())
+  , m_newMaskColor(newMask)
 {
 }
 
-void SetTotalFrames::dispose()
+void SetTransparentColor::onExecute()
 {
-  delete this;
+  sprite()->setTransparentColor(m_newMaskColor);
 }
 
-void SetTotalFrames::revert(ObjectsContainer* objects, UndoersCollector* redoers)
+void SetTransparentColor::onUndo()
 {
-  Document* document = objects->getObjectT<Document>(m_documentId);
-  Sprite* sprite = objects->getObjectT<Sprite>(m_spriteId);
-
-  document->getApi(redoers).setTotalFrames(sprite, m_totalFrames);
+  sprite()->setTransparentColor(m_oldMaskColor);
 }
 
-} // namespace undoers
+void SetTransparentColor::onFireNotifications()
+{
+  Sprite* sprite = this->sprite();
+  DocumentEvent ev(sprite->document());
+  ev.sprite(sprite);
+  sprite->document()->notifyObservers<DocumentEvent&>(&DocumentObserver::onSpriteTransparentColorChanged, ev);
+}
+
+} // namespace cmd
 } // namespace app

src/app/cmd/set_transparent_color.h

@@ -0,0 +1,52 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_SET_TRANSPARENT_COLOR_H_INCLUDED
+#define APP_CMD_SET_TRANSPARENT_COLOR_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_sprite.h"
+#include "doc/color.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetTransparentColor : public Cmd
+                            , public WithSprite {
+  public:
+    SetTransparentColor(Sprite* sprite, color_t newMask);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications();
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    color_t m_oldMaskColor;
+    color_t m_newMaskColor;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/with_cel.cpp

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,38 +20,24 @@
 #include "config.h"
 #endif
 
-#include "app/undoers/set_cel_position.h"
+#include "app/cmd/with_cel.h"
 
 #include "doc/cel.h"
-#include "undo/objects_container.h"
-#include "undo/undoers_collector.h"
 
 namespace app {
-namespace undoers {
+namespace cmd {
 
-using namespace undo;
+using namespace doc;
 
-SetCelPosition::SetCelPosition(ObjectsContainer* objects, Cel* cel)
-  : m_celId(objects->addObject(cel))
-  , m_x(cel->x())
-  , m_y(cel->y())
+WithCel::WithCel(Cel* cel)
+  : m_celId(cel->id())
 {
 }
 
-void SetCelPosition::dispose()
+Cel* WithCel::cel()
 {
-  delete this;
+  return get<Cel>(m_celId);
 }
 
-void SetCelPosition::revert(ObjectsContainer* objects, UndoersCollector* redoers)
-{
-  Cel* cel = objects->getObjectT<Cel>(m_celId);
-
-  // Push another SetCelPosition as redoer
-  redoers->pushUndoer(new SetCelPosition(objects, cel));
-
-  cel->setPosition(m_x, m_y);
-}
-
-} // namespace undoers
+} // namespace cmd
 } // namespace app

src/app/cmd/with_cel.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,37 +16,30 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_SET_CEL_OPACITY_H_INCLUDED
-#define APP_UNDOERS_SET_CEL_OPACITY_H_INCLUDED
+#ifndef APP_CMD_WITH_CEL_H_INCLUDED
+#define APP_CMD_WITH_CEL_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
-#include "undo/object_id.h"
+#include "doc/object_id.h"
 
 namespace doc {
   class Cel;
-  class Layer;
 }
 
 namespace app {
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+namespace cmd {
+  using namespace doc;
 
-    class SetCelOpacity : public UndoerBase {
-    public:
-      SetCelOpacity(ObjectsContainer* objects, Cel* cel);
+  class WithCel {
+  public:
+    WithCel(Cel* cel);
+    Cel* cel();
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  private:
+    ObjectId m_celId;
+  };
 
-    private:
-      undo::ObjectId m_celId;
-      uint8_t m_opacity;
-    };
-
-  } // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_SET_CEL_OPACITY_H_INCLUDED
+#endif

src/app/cmd/with_document.cpp

@@ -0,0 +1,41 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/with_document.h"
+
+#include "app/document.h"
+
+namespace app {
+namespace cmd {
+
+WithDocument::WithDocument(app::Document* doc)
+  : m_docId(doc->id())
+{
+}
+
+app::Document* WithDocument::document()
+{
+  return doc::get<app::Document>(m_docId);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/with_document.h

@@ -0,0 +1,41 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_WITH_DOCUMENT_H_INCLUDED
+#define APP_CMD_WITH_DOCUMENT_H_INCLUDED
+#pragma once
+
+#include "doc/object_id.h"
+
+namespace app {
+class Document;
+namespace cmd {
+
+  class WithDocument {
+  public:
+    WithDocument(app::Document* doc);
+    app::Document* document();
+
+  private:
+    doc::ObjectId m_docId;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/with_image.cpp

@@ -0,0 +1,43 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/with_image.h"
+
+#include "doc/image.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+WithImage::WithImage(Image* image)
+  : m_imageId(image->id())
+{
+}
+
+Image* WithImage::image()
+{
+  return get<Image>(m_imageId);
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/with_image.h

@@ -0,0 +1,45 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef APP_CMD_WITH_IMAGE_H_INCLUDED
+#define APP_CMD_WITH_IMAGE_H_INCLUDED
+#pragma once
+
+#include "doc/object_id.h"
+
+namespace doc {
+  class Image;
+}
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class WithImage {
+  public:
+    WithImage(Image* image);
+    Image* image();
+
+  private:
+    ObjectId m_imageId;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif

src/app/cmd/with_layer.cpp

@@ -0,0 +1,46 @@
+/* Aseprite
+ * Copyright (C) 2001-2015  David Capello
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/with_layer.h"
+
+#include "doc/layer.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+WithLayer::WithLayer(Layer* layer)
+  : m_layerId(layer ? layer->id(): 0)
+{
+}
+
+Layer* WithLayer::layer()
+{
+  if (m_layerId)
+    return get<Layer>(m_layerId);
+  else
+    return nullptr;
+}
+
+} // namespace cmd
+} // namespace app

src/app/cmd/with_layer.h

@@ -1,5 +1,5 @@
 /* Aseprite
- * Copyright (C) 2001-2013  David Capello
+ * Copyright (C) 2001-2015  David Capello
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,37 +16,30 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef APP_UNDOERS_ADD_CEL_H_INCLUDED
-#define APP_UNDOERS_ADD_CEL_H_INCLUDED
+#ifndef APP_CMD_WITH_LAYER_H_INCLUDED
+#define APP_CMD_WITH_LAYER_H_INCLUDED
 #pragma once
 
-#include "app/undoers/undoer_base.h"
-#include "undo/object_id.h"
+#include "doc/object_id.h"
 
 namespace doc {
-  class Cel;
   class Layer;
 }
 
 namespace app {
-  namespace undoers {
-    using namespace doc;
-    using namespace undo;
+namespace cmd {
+  using namespace doc;
 
-    class AddCel : public UndoerBase {
-    public:
-      AddCel(ObjectsContainer* objects, Layer* layer, Cel* cel);
+  class WithLayer {
+  public:
+    WithLayer(Layer* layer);
+    Layer* layer();
 
-      void dispose() override;
-      size_t getMemSize() const override { return sizeof(*this); }
-      void revert(ObjectsContainer* objects, UndoersCollector* redoers) override;
+  private:
+    ObjectId m_layerId;
+  };
 
-    private:
-      undo::ObjectId m_layerId;
-      undo::ObjectId m_celId;
-    };
-
-  } // namespace undoers
+} // namespace cmd
 } // namespace app
 
-#endif  // UNDOERS_ADD_CEL_H_INCLUDED
+#endif