Support drag and drop images as new documents

src/app/CMakeLists.txt

@@ -689,6 +689,7 @@ target_sources(app-lib PRIVATE
   util/cel_ops.cpp
   util/clipboard.cpp
   util/clipboard_native.cpp
+  util/conversion_to_image.cpp
   util/conversion_to_surface.cpp
   util/expand_cel_canvas.cpp
   util/filetoks.cpp

src/app/commands/cmd_new_file.cpp

@@ -46,6 +46,7 @@ struct NewFileParams : public NewParams {
   Param<int> height { this, 0, "height" };
   Param<ColorMode> colorMode { this, ColorMode::RGB, "colorMode" };
   Param<bool> fromClipboard { this, false, "fromClipboard" };
+  Param<bool> fromDraggedData { this, false, "fromDraggedData" };
 };
 
 class NewFileCommand : public CommandWithNewParams<NewFileParams> {
@@ -86,8 +87,9 @@ void NewFileCommand::onExecute(Context* ctx)
   doc::Palette clipboardPalette(0, 256);
   const int ncolors = get_default_palette()->size();
 
-  if (params().fromClipboard()) {
-    clipboardImage = ctx->clipboard()->getImage(&clipboardPalette);
+  if (params().fromClipboard() || params().fromDraggedData()) {
+    clipboardImage = (params().fromClipboard() ? ctx->clipboard()->getImage(&clipboardPalette)
+                                               : ctx->draggedData()->getImage());
     if (!clipboardImage)
       return;
 

src/app/context.h

@@ -14,11 +14,14 @@
 #include "app/context_observer.h"
 #include "app/docs.h"
 #include "app/docs_observer.h"
+#include "app/util/conversion_to_image.h"
 #include "base/disable_copying.h"
 #include "base/exception.h"
 #include "doc/frame.h"
+#include "doc/image_ref.h"
 #include "obs/observable.h"
 #include "obs/signal.h"
+#include "os/surface.h"
 
 #include <memory>
 #include <vector>
@@ -86,6 +89,22 @@ namespace app {
     bool m_canceled;
   };
 
+  class DraggedData
+  {
+  public:
+    DraggedData(const doc::ImageRef& image) {
+      m_image = image;
+    }
+    DraggedData(const os::SurfaceRef& surface) {
+      convert_surface_to_image(surface.get(), 0, 0, surface->width(), surface->height(), m_image);
+    }
+
+    const doc::ImageRef& getImage() const { return m_image; }
+
+  private:
+    doc::ImageRef m_image = nullptr;
+  };
+
   class Context : public obs::observable<ContextObserver>,
                   public DocsObserver {
   public:
@@ -120,6 +139,11 @@ namespace app {
     bool hasModifiedDocuments() const;
     void notifyActiveSiteChanged();
 
+    void setDraggedData(std::unique_ptr<DraggedData> draggedData) {
+      m_draggedData = std::move(draggedData);
+    }
+    const DraggedData* draggedData() const { return m_draggedData.get(); }
+
     void executeCommandFromMenuOrShortcut(Command* command, const Params& params = Params());
     virtual void executeCommand(Command* command, const Params& params = Params());
 
@@ -159,6 +183,7 @@ namespace app {
     ContextFlags m_flags;       // Last updated flags.
     Doc* m_lastSelectedDoc;
     mutable std::unique_ptr<Preferences> m_preferences;
+    std::unique_ptr<DraggedData> m_draggedData = nullptr;
 
     // Result of the execution of a command.
     CommandResult m_result;

src/app/ui/main_window.cpp

@@ -39,7 +39,10 @@
 #include "app/ui/workspace_tabs.h"
 #include "app/ui_context.h"
 #include "base/fs.h"
+#include "os/event.h"
+#include "os/event_queue.h"
 #include "os/system.h"
+#include "ui/drag_event.h"
 #include "ui/message.h"
 #include "ui/splitter.h"
 #include "ui/system.h"
@@ -91,6 +94,7 @@ MainWindow::MainWindow()
   , m_devConsoleView(nullptr)
 #endif
 {
+  enableFlags(ALLOW_DROP);
 }
 
 // This 'initialize' function is a way to split the creation of the
@@ -434,6 +438,22 @@ void MainWindow::onActiveViewChange()
     UIContext::instance()->setActiveView(nullptr);
 }
 
+void MainWindow::onDrop(ui::DragEvent& e)
+{
+  if (e.hasImage()) {
+    auto* cmd = Commands::instance()->byId(CommandId::NewFile());
+    Params params;
+    params.set("fromDraggedData", "true");
+    UIContext::instance()->setDraggedData(std::make_unique<DraggedData>(e.getImage()));
+    UIContext::instance()->executeCommand(cmd, params);
+    e.handled(true);
+    invalidate();
+    flushRedraw();
+    os::Event ev;
+    os::System::instance()->eventQueue()->queueEvent(ev);
+  }
+}
+
 bool MainWindow::isTabModified(Tabs* tabs, TabView* tabView)
 {
   if (DocView* docView = dynamic_cast<DocView*>(tabView)) {

src/app/ui/main_window.h

@@ -119,6 +119,8 @@ namespace app {
     void onActiveViewChange();
     void onLanguageChange();
 
+    void onDrop(ui::DragEvent& e) override;
+
   private:
     DocView* getDocView();
     HomeView* getHomeView();

src/app/util/conversion_to_image.cpp

@@ -0,0 +1,53 @@
+// Aseprite
+// Copyright (c) 2024  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/util/conversion_to_image.h"
+
+#include "doc/image_traits.h"
+#include "doc/pixel_format.h"
+#include "os/surface.h"
+
+#include <memory>
+
+namespace app {
+
+using namespace doc;
+
+// TODO: This implementation has a lot of room for improvement, I made the bare
+// minimum to make it work. Right now it only supports converting RGBA surfaces,
+// other kind of surfaces won't be converted to an image as expected.
+void convert_surface_to_image(
+  const os::Surface* surface,
+  int src_x, int src_y,
+  int w, int h,
+  ImageRef& image)
+{
+  gfx::Rect srcBounds(src_x, src_y, w, h);
+  srcBounds = srcBounds.createIntersection(surface->getClipBounds());
+  if (srcBounds.isEmpty())
+    return;
+
+  src_x = srcBounds.x;
+  src_y = srcBounds.y;
+  w = srcBounds.w;
+  h = srcBounds.h;
+
+  image.reset(Image::create(PixelFormat::IMAGE_RGB, w, h));
+
+  for (int v=0; v<h; ++v, ++src_y) {
+    uint8_t* src_address = surface->getData(0, v);
+    uint8_t* dst_address = image->getPixelAddress(src_x, src_y);
+    std::copy(src_address,
+              src_address + RgbTraits::bytes_per_pixel * w,
+              dst_address);
+  }
+}
+
+} // namespace app

src/app/util/conversion_to_image.h

@@ -0,0 +1,31 @@
+// Aseprite
+// Copyright (c) 2024  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifndef APP_UTIL_CONVERSION_TO_IMAGE_H_INCLUDED
+#define APP_UTIL_CONVERSION_TO_IMAGE_H_INCLUDED
+#pragma once
+
+#include "doc/image_ref.h"
+
+namespace os {
+  class Surface;
+}
+
+namespace doc {
+  class Palette;
+}
+
+namespace app {
+
+void convert_surface_to_image(
+  const os::Surface* surface,
+  int src_x, int src_y,
+  int w, int h,
+  doc::ImageRef& image);
+
+} // namespace app
+
+#endif

src/ui/manager.cpp

@@ -2056,7 +2056,7 @@ void Manager::dragEnter(os::DragEvent& ev)
 {
   Widget* widget = pickForDragAndDrop(ev.position());
 
-  ASSERT(widget->hasFlags(ALLOW_DROP));
+  ASSERT(!widget || widget && widget->hasFlags(ALLOW_DROP));
 
   if (widget) {
     m_dragOverWidget = widget;
@@ -2080,7 +2080,7 @@ void Manager::drag(os::DragEvent& ev)
 {
   Widget* widget = pickForDragAndDrop(ev.position());
 
-  ASSERT(widget->hasFlags(ALLOW_DROP));
+  ASSERT(!widget || widget && widget->hasFlags(ALLOW_DROP));
 
   if (m_dragOverWidget && m_dragOverWidget != widget) {
     DragEvent uiev(this, m_dragOverWidget, ev);
@@ -2104,7 +2104,7 @@ void Manager::drop(os::DragEvent& ev)
   m_dragOverWidget = nullptr;
   Widget* widget = pickForDragAndDrop(ev.position());
 
-  ASSERT(widget->hasFlags(ALLOW_DROP));
+  ASSERT(!widget || widget && widget->hasFlags(ALLOW_DROP));
 
   if (widget) {
     DragEvent uiev(this, widget, ev);