diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
index e60bf8945..e5cef9da4 100644
--- a/src/app/CMakeLists.txt
+++ b/src/app/CMakeLists.txt
@@ -100,6 +100,7 @@ add_library(app-library
   data_recovery.cpp
   document.cpp
   document_api.cpp
+  document_exporter.cpp
   document_location.cpp
   document_undo.cpp
   documents.cpp
diff --git a/src/app/app.cpp b/src/app/app.cpp
index ccd04a131..7e4ce759e 100644
--- a/src/app/app.cpp
+++ b/src/app/app.cpp
@@ -29,6 +29,7 @@
 #include "app/commands/params.h"
 #include "app/console.h"
 #include "app/data_recovery.h"
+#include "app/document_exporter.h"
 #include "app/document_location.h"
 #include "app/document_observer.h"
 #include "app/drop_files.h"
@@ -112,6 +113,7 @@ App::App(int argc, const char* argv[])
   , m_legacy(NULL)
   , m_isGui(false)
   , m_isShell(false)
+  , m_exporter(NULL)
 {
   ASSERT(m_instance == NULL);
   m_instance = this;
@@ -124,6 +126,14 @@ App::App(int argc, const char* argv[])
   m_legacy = new LegacyModules(isGui() ? REQUIRE_INTERFACE: 0);
   m_files = options.files();
 
+  if (options.hasExporterParams()) {
+    m_exporter.reset(new DocumentExporter);
+
+    m_exporter->setDataFilename(options.data());
+    m_exporter->setTextureFilename(options.sheet());
+    m_exporter->setScale(options.scale());
+  }
+
   // Register well-known image file types.
   FileFormatsManager::instance().registerAllFormats();
 
@@ -186,6 +196,7 @@ int App::run()
   PRINTF("Processing options...\n");
 
   {
+    UIContext* context = UIContext::instance();
     Console console;
     for (FileList::iterator
            it  = m_files.begin(),
@@ -199,17 +210,29 @@ int App::run()
       }
       else {
         // Mount and select the sprite
-        UIContext* context = UIContext::instance();
         context->addDocument(document);
 
-        if (isGui()) {
-          // Recent file
+        // Add the given file in the argument as a "recent file" only
+        // if we are running in GUI mode. If the program is executed
+        // in batch mode this is not desirable.
+        if (isGui())
           getRecentFiles()->addRecentFile(it->c_str());
-        }
+
+        // Add the document to the exporter.
+        if (m_exporter != NULL)
+          m_exporter->addDocument(document);
       }
     }
   }
 
+  // Export
+  if (m_exporter != NULL) {
+    PRINTF("Exporting sheet...\n");
+
+    m_exporter->exportSheet();
+    m_exporter.reset(NULL);
+  }
+
   // Run the GUI
   if (isGui()) {
     // Support to drop files from Windows explorer
diff --git a/src/app/app.h b/src/app/app.h
index 8b46d38be..5ea9f8107 100644
--- a/src/app/app.h
+++ b/src/app/app.h
@@ -39,6 +39,7 @@ namespace raster {
 
 namespace app {
   class Document;
+  class DocumentExporter;
   class LegacyModules;
   class LoggerModule;
   class MainWindow;
@@ -90,6 +91,7 @@ namespace app {
     bool m_isShell;
     base::UniquePtr<MainWindow> m_mainWindow;
     FileList m_files;
+    base::UniquePtr<DocumentExporter> m_exporter;
   };
 
   void app_refresh_screen();
diff --git a/src/app/app_options.cpp b/src/app/app_options.cpp
index 1a79c9d4c..19c2a43ab 100644
--- a/src/app/app_options.cpp
+++ b/src/app/app_options.cpp
@@ -24,6 +24,7 @@
 
 #include "base/path.h"
 
+#include <cstdlib>
 #include <iostream>
 
 namespace app {
@@ -35,10 +36,20 @@ AppOptions::AppOptions(int argc, const char* argv[])
   , m_startUI(true)
   , m_startShell(false)
   , m_verbose(false)
+  , m_scale(1.0)
 {
-  Option& palette = m_po.add("palette").requiresValue("GFXFILE").description("Use a specific palette by default");
+  Option& palette = m_po.add("palette").requiresValue("<filename>").description("Use a specific palette by default");
   Option& shell = m_po.add("shell").description("Start an interactive console to execute scripts");
   Option& batch = m_po.add("batch").description("Do not start the UI");
+  // Option& dataFormat = m_po.add("format").requiresValue("<name>").description("Select the format for the sprite sheet data");
+  Option& data = m_po.add("data").requiresValue("<filename>").description("File to store the sprite sheet metadata (.json file)");
+  //Option& textureFormat = m_po.add("texture-format").requiresValue("<name>").description("Output texture format.");
+  Option& sheet = m_po.add("sheet").requiresValue("<filename>").description("Image file to save the texture (.png)");
+  //Option& scale = m_po.add("scale").requiresValue("<float>").description("");
+  //Option& scaleMode = m_po.add("scale-mode").requiresValue("<mode>").description("Export the first given document to a JSON object");
+  //Option& splitLayers = m_po.add("split-layers").description("Specifies that each layer of the given file should be saved as a different image in the sheet.");
+  //Option& rotsprite = m_po.add("rotsprite").requiresValue("<angle1,angle2,...>").description("Specifies different angles to export the given image.");
+  //Option& merge = m_po.add("merge").requiresValue("<datafiles>").description("Merge several sprite sheets in one.");
   Option& verbose = m_po.add("verbose").description("Explain what is being done (in stderr or a log file)");
   Option& help = m_po.add("help").mnemonic('?').description("Display this help and exits");
   Option& version = m_po.add("version").description("Output version information and exit");
@@ -49,6 +60,13 @@ AppOptions::AppOptions(int argc, const char* argv[])
     m_verbose = verbose.enabled();
     m_paletteFileName = palette.value();
     m_startShell = shell.enabled();
+    // m_dataFormat = dataFormat.value();
+    m_data = data.value();
+    // m_textureFormat = textureFormat.value();
+    m_sheet = sheet.value();
+    // if (scale.enabled())
+    //   m_scale = std::strtod(scale.value().c_str(), NULL);
+    // m_scaleMode = scaleMode.value();
 
     if (help.enabled()) {
       showHelp();
diff --git a/src/app/app_options.h b/src/app/app_options.h
index cd1bdeb4a..fa7b4dc62 100644
--- a/src/app/app_options.h
+++ b/src/app/app_options.h
@@ -41,6 +41,22 @@ public:
     return m_po.values();
   }
 
+  // Export options
+  const std::string& dataFormat() const { return m_dataFormat; }
+  const std::string& data() const { return m_data; }
+  const std::string& textureFormat() const { return m_textureFormat; }
+  const std::string& sheet() const { return m_sheet; }
+  const double scale() const { return m_scale; }
+  const std::string& scaleMode() const { return m_scaleMode; }
+
+  bool hasExporterParams() {
+    return
+      !m_dataFormat.empty() ||
+      !m_data.empty() ||
+      !m_textureFormat.empty() ||
+      !m_sheet.empty();
+  }
+
 private:
   void showHelp();
   void showVersion();
@@ -51,6 +67,13 @@ private:
   bool m_startShell;
   bool m_verbose;
   std::string m_paletteFileName;
+
+  std::string m_dataFormat;
+  std::string m_data;
+  std::string m_textureFormat;
+  std::string m_sheet;
+  double m_scale;
+  std::string m_scaleMode;
 };
 
 } // namespace app
diff --git a/src/app/document_api.cpp b/src/app/document_api.cpp
index 2e71a55ab..0a9ca695c 100644
--- a/src/app/document_api.cpp
+++ b/src/app/document_api.cpp
@@ -91,8 +91,7 @@ void DocumentApi::setSpriteSize(Sprite* sprite, int w, int h)
   ASSERT(w > 0);
   ASSERT(h > 0);
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetSpriteSize(getObjects(), sprite));
 
   sprite->setSize(w, h);
@@ -151,8 +150,7 @@ void DocumentApi::setPixelFormat(Sprite* sprite, PixelFormat newFormat, Ditherin
     return;
 
   // Change pixel format of the stock of images.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetStockPixelFormat(getObjects(), sprite->getStock()));
 
   sprite->getStock()->setPixelFormat(newFormat);
@@ -177,7 +175,7 @@ void DocumentApi::setPixelFormat(Sprite* sprite, PixelFormat newFormat, Ditherin
   }
 
   // Change sprite's pixel format.
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetSpritePixelFormat(getObjects(), sprite));
 
   sprite->setPixelFormat(newFormat);
@@ -190,7 +188,7 @@ void DocumentApi::setPixelFormat(Sprite* sprite, PixelFormat newFormat, Ditherin
   // frame.
   if (newFormat == IMAGE_GRAYSCALE) {
     // Add undoers to revert all palette changes.
-    if (undo->isEnabled()) {
+    if (undoEnabled()) {
       PalettesList palettes = sprite->getPalettes();
       for (PalettesList::iterator it = palettes.begin(); it != palettes.end(); ++it) {
         Palette* palette = *it;
@@ -217,8 +215,7 @@ void DocumentApi::addFrame(Sprite* sprite, FrameNumber newFrame)
 
   // Add the frame in the sprite structure, it adjusts the total
   // number of frames in the sprite.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::AddFrame(getObjects(), m_document, sprite, newFrame));
 
   sprite->addFrame(newFrame);
@@ -303,8 +300,7 @@ void DocumentApi::removeFrame(Sprite* sprite, FrameNumber frame)
 
   // Add undoers to restore the removed frame from the sprite (to
   // restore the number and durations of frames).
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::RemoveFrame(getObjects(), m_document, sprite, frame));
 
   // Remove the frame from the sprite. This is the low level
@@ -355,8 +351,7 @@ void DocumentApi::setTotalFrames(Sprite* sprite, FrameNumber frames)
   ASSERT(frames >= 1);
 
   // Add undoers.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetTotalFrames(getObjects(), m_document, sprite));
 
   // Do the action.
@@ -372,8 +367,7 @@ void DocumentApi::setTotalFrames(Sprite* sprite, FrameNumber frames)
 void DocumentApi::setFrameDuration(Sprite* sprite, FrameNumber frame, int msecs)
 {
   // Add undoers.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetFrameDuration(
         getObjects(), sprite, frame));
 
@@ -390,8 +384,7 @@ void DocumentApi::setFrameDuration(Sprite* sprite, FrameNumber frame, int msecs)
 void DocumentApi::setConstantFrameRate(Sprite* sprite, int msecs)
 {
   // Add undoers.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled()) {
+  if (undoEnabled()) {
     for (FrameNumber fr(0); fr<sprite->getTotalFrames(); ++fr)
       m_undoers->pushUndoer(new undoers::SetFrameDuration(
           getObjects(), sprite, fr));
@@ -489,8 +482,7 @@ void DocumentApi::addCel(LayerImage* layer, Cel* cel)
   ASSERT(layer);
   ASSERT(cel);
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::AddCel(getObjects(), layer, cel));
 
   layer->addCel(cel);
@@ -531,8 +523,7 @@ void DocumentApi::removeCel(LayerImage* layer, Cel* cel)
   if (!used)
     removeImageFromStock(sprite, cel->getImage());
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::RemoveCel(getObjects(),
         layer, cel));
 
@@ -548,8 +539,7 @@ void DocumentApi::setCelFramePosition(Sprite* sprite, Cel* cel, FrameNumber fram
   ASSERT(cel);
   ASSERT(frame >= 0);
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetCelFrame(getObjects(), cel));
 
   cel->setFrame(frame);
@@ -565,8 +555,7 @@ void DocumentApi::setCelPosition(Sprite* sprite, Cel* cel, int x, int y)
 {
   ASSERT(cel);
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetCelPosition(getObjects(), cel));
 
   cel->setPosition(x, y);
@@ -615,8 +604,7 @@ LayerFolder* DocumentApi::newLayerFolder(Sprite* sprite)
 void DocumentApi::addLayer(LayerFolder* folder, Layer* newLayer, Layer* afterThis)
 {
   // Add undoers.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::AddLayer(getObjects(),
                                                 m_document, newLayer));
 
@@ -643,8 +631,7 @@ void DocumentApi::removeLayer(Layer* layer)
   m_document->notifyObservers<DocumentEvent&>(&DocumentObserver::onRemoveLayer, ev);
 
   // Add undoers.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::RemoveLayer(getObjects(), m_document, layer));
 
   // Do the action.
@@ -655,8 +642,7 @@ void DocumentApi::removeLayer(Layer* layer)
 void DocumentApi::configureLayerAsBackground(LayerImage* layer)
 {
   // Add undoers.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled()) {
+  if (undoEnabled()) {
     m_undoers->pushUndoer(new undoers::SetLayerFlags(getObjects(), layer));
     m_undoers->pushUndoer(new undoers::SetLayerName(getObjects(), layer));
     m_undoers->pushUndoer(new undoers::MoveLayer(getObjects(), layer));
@@ -668,8 +654,7 @@ void DocumentApi::configureLayerAsBackground(LayerImage* layer)
 
 void DocumentApi::restackLayerAfter(Layer* layer, Layer* afterThis)
 {
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::MoveLayer(getObjects(), layer));
 
   layer->getParent()->stackLayer(layer, afterThis);
@@ -730,7 +715,6 @@ void DocumentApi::backgroundFromLayer(LayerImage* layer, int bgcolor)
   ASSERT(layer->getSprite() != NULL);
   ASSERT(layer->getSprite()->getBackgroundLayer() == NULL);
 
-  DocumentUndo* undo = m_document->getUndo();
   Sprite* sprite = layer->getSprite();
 
   // create a temporary image to draw each frame of the new
@@ -765,7 +749,7 @@ void DocumentApi::backgroundFromLayer(LayerImage* layer, int bgcolor)
     // same size of cel-image and bg-image
     if (bg_image->getWidth() == cel_image->getWidth() &&
         bg_image->getHeight() == cel_image->getHeight()) {
-      if (undo->isEnabled())
+      if (undoEnabled())
         m_undoers->pushUndoer(new undoers::ImageArea(getObjects(),
           cel_image, 0, 0, cel_image->getWidth(), cel_image->getHeight()));
 
@@ -805,8 +789,7 @@ void DocumentApi::layerFromBackground(Layer* layer)
   ASSERT(layer->getSprite() != NULL);
   ASSERT(layer->getSprite()->getBackgroundLayer() != NULL);
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled()) {
+  if (undoEnabled()) {
     m_undoers->pushUndoer(new undoers::SetLayerFlags(getObjects(), layer));
     m_undoers->pushUndoer(new undoers::SetLayerName(getObjects(), layer));
   }
@@ -821,8 +804,6 @@ void DocumentApi::flattenLayers(Sprite* sprite, int bgcolor)
   Image* cel_image;
   Cel* cel;
 
-  DocumentUndo* undo = m_document->getUndo();
-
   // Create a temporary image.
   base::UniquePtr<Image> image_wrap(Image::create(sprite->getPixelFormat(),
                                             sprite->getWidth(),
@@ -851,7 +832,7 @@ void DocumentApi::flattenLayers(Sprite* sprite, int bgcolor)
       ASSERT(cel_image != NULL);
 
       // We have to save the current state of `cel_image' in the undo.
-      if (undo->isEnabled()) {
+      if (undoEnabled()) {
         Dirty* dirty = new Dirty(cel_image, image, image->getBounds());
         dirty->saveImagePixels(cel_image);
         m_undoers->pushUndoer(new undoers::DirtyArea(
@@ -895,8 +876,7 @@ int DocumentApi::addImageInStock(Sprite* sprite, Image* image)
   int imageIndex = sprite->getStock()->addImage(image);
 
   // Add undoers.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::AddImage(getObjects(),
         sprite->getStock(), imageIndex));
 
@@ -911,8 +891,7 @@ void DocumentApi::removeImageFromStock(Sprite* sprite, int imageIndex)
   Image* image = sprite->getStock()->getImage(imageIndex);
   ASSERT(image);
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::RemoveImage(getObjects(),
         sprite->getStock(), imageIndex));
 
@@ -927,8 +906,7 @@ void DocumentApi::replaceStockImage(Sprite* sprite, int imageIndex, Image* newIm
   ASSERT(oldImage);
 
   // Replace the image in the stock.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::ReplaceImage(getObjects(),
         sprite->getStock(), imageIndex));
 
@@ -952,14 +930,13 @@ void DocumentApi::clearMask(Layer* layer, Cel* cel, int bgcolor)
     return;
 
   Mask* mask = m_document->getMask();
-  DocumentUndo* undo = m_document->getUndo();
 
   // If the mask is empty or is not visible then we have to clear the
   // entire image in the cel.
   if (!m_document->isMaskVisible()) {
     // If the layer is the background then we clear the image.
     if (layer->isBackground()) {
-      if (undo->isEnabled())
+      if (undoEnabled())
         m_undoers->pushUndoer(new undoers::ImageArea(getObjects(),
           image, 0, 0, image->getWidth(), image->getHeight()));
 
@@ -986,7 +963,7 @@ void DocumentApi::clearMask(Layer* layer, Cel* cel, int bgcolor)
     if (x1 > x2 || y1 > y2)
       return;
 
-    if (undo->isEnabled())
+    if (undoEnabled())
       m_undoers->pushUndoer(new undoers::ImageArea(getObjects(),
           image, x1, y1, x2-x1+1, y2-y1+1));
 
@@ -1014,8 +991,7 @@ void DocumentApi::flipImage(Image* image,
                                 raster::algorithm::FlipType flipType)
 {
   // Insert the undo operation.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled()) {
+  if (undoEnabled()) {
     m_undoers->pushUndoer
       (new undoers::FlipImage
        (getObjects(), image, bounds, flipType));
@@ -1033,8 +1009,7 @@ void DocumentApi::flipImageWithMask(Image* image, const Mask* mask, raster::algo
   raster::algorithm::flip_image_with_mask(flippedImage, mask, flipType, bgcolor);
 
   // Insert the undo operation.
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled()) {
+  if (undoEnabled()) {
     base::UniquePtr<Dirty> dirty((new Dirty(image, flippedImage, image->getBounds())));
     dirty->saveImagePixels(image);
 
@@ -1061,8 +1036,7 @@ void DocumentApi::copyToCurrentMask(Mask* mask)
   ASSERT(m_document->getMask());
   ASSERT(mask);
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetMask(getObjects(),
         m_document));
 
@@ -1073,8 +1047,7 @@ void DocumentApi::setMaskPosition(int x, int y)
 {
   ASSERT(m_document->getMask());
 
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetMaskPosition(getObjects(), m_document));
 
   m_document->getMask()->setOrigin(x, y);
@@ -1083,8 +1056,7 @@ void DocumentApi::setMaskPosition(int x, int y)
 
 void DocumentApi::deselectMask()
 {
-  DocumentUndo* undo = m_document->getUndo();
-  if (undo->isEnabled())
+  if (undoEnabled())
     m_undoers->pushUndoer(new undoers::SetMask(getObjects(),
         m_document));
 
@@ -1101,10 +1073,8 @@ void DocumentApi::setPalette(Sprite* sprite, FrameNumber frame, Palette* newPale
   currentSpritePalette->countDiff(newPalette, &from, &to);
 
   if (from >= 0 && to >= from) {
-    DocumentUndo* undo = m_document->getUndo();
-
     // Add undo information to save the range of pal entries that will be modified.
-    if (undo->isEnabled()) {
+    if (undoEnabled()) {
       m_undoers->pushUndoer
         (new undoers::SetPaletteColors(getObjects(),
                                        sprite, currentSpritePalette,
@@ -1116,4 +1086,11 @@ void DocumentApi::setPalette(Sprite* sprite, FrameNumber frame, Palette* newPale
   }
 }
 
+bool DocumentApi::undoEnabled()
+{
+  return
+    m_undoers != NULL &&
+    m_document->getUndo()->isEnabled();
+}
+
 } // namespace app
diff --git a/src/app/document_api.h b/src/app/document_api.h
index efa342135..1475ee664 100644
--- a/src/app/document_api.h
+++ b/src/app/document_api.h
@@ -118,6 +118,7 @@ namespace app {
     void copyPreviousFrame(Layer* layer, FrameNumber frame);
     void moveFrameBeforeLayer(Layer* layer, FrameNumber frame, FrameNumber beforeFrame);
     void configureLayerAsBackground(LayerImage* layer);
+    bool undoEnabled();
 
     Document* m_document;
     undo::UndoersCollector* m_undoers;
diff --git a/src/app/document_exporter.cpp b/src/app/document_exporter.cpp
new file mode 100644
index 000000000..c0ab73348
--- /dev/null
+++ b/src/app/document_exporter.cpp
@@ -0,0 +1,329 @@
+/* Aseprite
+ * Copyright (C) 2001-2013  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/document_exporter.h"
+
+#include "app/document.h"
+#include "app/document_api.h"
+#include "app/file/file.h"
+#include "base/compiler_specific.h"
+#include "base/path.h"
+#include "base/unique_ptr.h"
+#include "gfx/size.h"
+#include "raster/cel.h"
+#include "raster/dithering_method.h"
+#include "raster/image.h"
+#include "raster/layer.h"
+#include "raster/palette.h"
+#include "raster/sprite.h"
+#include "raster/stock.h"
+
+#include <cstdio>
+#include <fstream>
+#include <iostream>
+
+using namespace raster;
+
+namespace app {
+
+class DocumentExporter::Sample {
+public:
+  Sample(Document* document, Sprite* sprite,
+    FrameNumber frame, const std::string& filename) :
+    m_document(document),
+    m_sprite(sprite),
+    m_frame(frame),
+    m_filename(filename) {
+  }
+
+  Document* document() const { return m_document; }
+  Sprite* sprite() const { return m_sprite; }
+  FrameNumber frame() const { return m_frame; }
+  std::string filename() const { return m_filename; }
+  const gfx::Size& originalSize() const { return m_originalSize; }
+  const gfx::Rect& trimmedBounds() const { return m_trimmedBounds; }
+  const gfx::Rect& inTextureBounds() const { return m_inTextureBounds; }
+
+  bool trimmed() const {
+    return m_trimmedBounds.x > 0
+      || m_trimmedBounds.y > 0
+      || m_trimmedBounds.w != m_originalSize.w
+      || m_trimmedBounds.h != m_originalSize.h;
+  }
+
+  void setOriginalSize(const gfx::Size& size) { m_originalSize = size; }
+  void setTrimmedBounds(const gfx::Rect& bounds) { m_trimmedBounds = bounds; }
+  void setInTextureBounds(const gfx::Rect& bounds) { m_inTextureBounds = bounds; }
+
+private:
+  Document* m_document;
+  Sprite* m_sprite;
+  FrameNumber m_frame;
+  std::string m_filename;
+  gfx::Size m_originalSize;
+  gfx::Rect m_trimmedBounds;
+  gfx::Rect m_inTextureBounds;
+};
+
+class DocumentExporter::Samples {
+public:
+  typedef std::list<Sample> List;
+  typedef List::iterator iterator;
+  typedef List::const_iterator const_iterator;
+
+  void addSample(const Sample& sample) {
+    m_samples.push_back(sample);
+  }
+
+  iterator begin() { return m_samples.begin(); }
+  iterator end() { return m_samples.end(); }
+  const_iterator begin() const { return m_samples.begin(); }
+  const_iterator end() const { return m_samples.end(); }
+
+private:
+  List m_samples;
+};
+
+class DocumentExporter::LayoutSamples {
+public:
+  virtual ~LayoutSamples() { }
+  virtual void layoutSamples(Samples& samples) = 0;
+};
+
+class DocumentExporter::SimpleLayoutSamples :
+    public DocumentExporter::LayoutSamples {
+public:
+  void layoutSamples(Samples& samples) OVERRIDE {
+    const Sprite* oldSprite = NULL;
+
+    gfx::Point framePt(0, 0);
+    for (Samples::iterator it=samples.begin(), end=samples.end();
+         it != end; ++it) {
+      const Sprite* sprite = it->sprite();
+      gfx::Size size(sprite->getWidth(), sprite->getHeight());
+
+      it->setOriginalSize(size);
+      it->setTrimmedBounds(gfx::Rect(gfx::Point(0, 0), size));
+      it->setInTextureBounds(gfx::Rect(framePt, size));
+
+      // All frames of each sprite in one row.
+      if (oldSprite != NULL && oldSprite != it->sprite()) {
+        framePt.x = 0;
+        framePt.y += size.h;
+      }
+      else {
+        framePt.x += size.w;
+      }
+
+      oldSprite = it->sprite();
+    }
+  }
+};
+
+void DocumentExporter::exportSheet()
+{
+  // We output the metadata to std::cout if the user didn't specify a file.
+  std::ofstream fos;
+  std::streambuf* osbuf;
+  if (m_dataFilename.empty())
+    osbuf = std::cout.rdbuf();
+  else {
+    fos.open(m_dataFilename.c_str(), std::ios::out);
+    osbuf = fos.rdbuf();
+  }
+  std::ostream os(osbuf);
+
+  // Steps for sheet construction:
+  // 1) Capture the samples (each sprite+frame pair)
+  Samples samples;
+  captureSamples(samples);
+
+  // 2) Layout those samples in a texture field.
+  SimpleLayoutSamples layout;
+  layout.layoutSamples(samples);
+
+  // 3) Create and render the texture.
+  base::UniquePtr<Document> textureDocument(
+    createEmptyTexture(samples));
+
+  Sprite* texture = textureDocument->getSprite();
+  Image* textureImage = texture->getStock()->getImage(
+    static_cast<LayerImage*>(texture->getFolder()->getFirstLayer())
+      ->getCel(FrameNumber(0))->getImage());
+
+  renderTexture(samples, textureImage);
+
+  // Save the metadata.
+  createDataFile(samples, os, textureImage);
+
+  // Save the image files.
+  if (!m_textureFilename.empty()) {
+    textureDocument->setFilename(m_textureFilename.c_str());
+    save_document(textureDocument.get());
+  }
+}
+
+void DocumentExporter::captureSamples(Samples& samples)
+{
+  std::vector<char> buf(32);
+
+  for (std::vector<Document*>::iterator
+         it = m_documents.begin(),
+         end = m_documents.end(); it != end; ++it) {
+    Document* document = *it;
+    Sprite* sprite = document->getSprite();
+    
+    for (FrameNumber frame=FrameNumber(0);
+         frame<sprite->getTotalFrames(); ++frame) {
+      base::string filename = document->getFilename();
+
+      if (sprite->getTotalFrames() > FrameNumber(1)) {
+        int frameNumWidth =
+          (sprite->getTotalFrames() < 10)? 1:
+          (sprite->getTotalFrames() < 100)? 2:
+          (sprite->getTotalFrames() < 1000)? 3: 4;
+        std::sprintf(&buf[0], "%0*d", frameNumWidth, frame);
+
+        base::string path = base::get_file_path(filename);
+        base::string title = base::get_file_title(filename);
+        base::string ext = base::get_file_extension(filename);
+        filename = base::join_path(path, title + &buf[0] + "." + ext);
+      }
+
+      samples.addSample(Sample(document, sprite, frame, filename));
+    }
+  }
+}
+
+Document* DocumentExporter::createEmptyTexture(const Samples& samples)
+{
+  Palette* palette = NULL;
+  PixelFormat pixelFormat = IMAGE_INDEXED;
+  gfx::Rect fullTextureBounds;
+  int maxColors = 256;
+
+  for (Samples::const_iterator
+         it = samples.begin(),
+         end = samples.end(); it != end; ++it) {
+    // We try to render an indexed image. But if we find a sprite with
+    // two or more palettes, or two of the sprites have different
+    // palettes, we've to use RGB format.
+    if (pixelFormat == IMAGE_INDEXED) {
+      if (it->sprite()->getPixelFormat() != IMAGE_INDEXED) {
+        pixelFormat = IMAGE_RGB;
+      }
+      else if (it->sprite()->getPalettes().size() > 1) {
+        pixelFormat = IMAGE_RGB;
+      }
+      else if (palette != NULL
+        && palette->countDiff(it->sprite()->getPalette(FrameNumber(0)), NULL, NULL) > 0) {
+        pixelFormat = IMAGE_RGB;
+      }
+      else
+        palette = it->sprite()->getPalette(FrameNumber(0));
+    }
+
+    fullTextureBounds = fullTextureBounds.createUnion(it->inTextureBounds());
+  }
+
+  base::UniquePtr<Document> document(Document::createBasicDocument(pixelFormat,
+      fullTextureBounds.w, fullTextureBounds.h, maxColors));
+
+  if (palette != NULL)
+    document->getSprite()->setPalette(palette, false);
+
+  return document.release();
+}
+
+void DocumentExporter::renderTexture(const Samples& samples, Image* textureImage)
+{
+  textureImage->clear(0);
+
+  for (Samples::const_iterator
+         it = samples.begin(),
+         end = samples.end(); it != end; ++it) {
+    // Make the sprite compatible with the texture so the render()
+    // works correctly.
+    if (it->sprite()->getPixelFormat() != textureImage->getPixelFormat()) {
+      DocumentApi docApi(it->document(), NULL); // DocumentApi without undo
+      docApi.setPixelFormat(it->sprite(), textureImage->getPixelFormat(),
+        DITHERING_NONE);
+    }
+
+    it->sprite()->render(textureImage,
+      it->inTextureBounds().x - it->trimmedBounds().x,
+      it->inTextureBounds().y - it->trimmedBounds().y,
+      it->frame());
+  }
+}
+
+void DocumentExporter::createDataFile(const Samples& samples, std::ostream& os, Image* textureImage)
+{
+  os << "{ \"frames\": {\n";
+  for (Samples::const_iterator
+         it = samples.begin(),
+         end = samples.end(); it != end; ) {
+    gfx::Size srcSize = it->originalSize();
+    gfx::Rect spriteSourceBounds = it->trimmedBounds();
+    gfx::Rect frameBounds = it->inTextureBounds();
+
+    os << "   \"" << it->filename() << "\": {\n"
+       << "    \"frame\": { "
+       << "\"x\": " << frameBounds.x << ", "
+       << "\"y\": " << frameBounds.y << ", "
+       << "\"w\": " << frameBounds.w << ", "
+       << "\"h\": " << frameBounds.h << " },\n"
+       << "    \"rotated\": false,\n"
+       << "    \"trimmed\": " << (it->trimmed() ? "true": "false") << ",\n"
+       << "    \"spriteSourceSize\": { "
+       << "\"x\": " << spriteSourceBounds.x << ", "
+       << "\"y\": " << spriteSourceBounds.y << ", "
+       << "\"w\": " << spriteSourceBounds.w << ", "
+       << "\"h\": " << spriteSourceBounds.h << " },\n"
+       << "    \"sourceSize\": { "
+       << "\"w\": " << srcSize.w << ", "
+       << "\"h\": " << srcSize.h << " },\n"
+       << "    \"duration\": " << it->sprite()->getFrameDuration(it->frame()) << "\n"
+       << "   }";
+
+    if (++it != samples.end())
+      os << ",\n";
+    else
+      os << "\n";
+  }
+
+  os << " },\n"
+     << " \"meta\": {\n"
+     << "  \"app\": \"" << WEBSITE << "\",\n"
+     << "  \"version\": \"" << VERSION << "\",\n";
+  if (!m_textureFilename.empty())
+    os << "  \"image\": \"" << m_textureFilename.c_str() << "\",\n";
+  os << "  \"format\": \"" << (textureImage->getPixelFormat() == IMAGE_RGB ? "RGBA8888": "I8") << "\",\n"
+     << "  \"size\": { "
+     << "\"w\": " << textureImage->getWidth() << ", "
+     << "\"h\": " << textureImage->getHeight() << " },\n"
+     << "  \"scale\": \"" << m_scale << "\"\n"
+     << " }\n"
+     << "}\n";
+}
+
+} // namespace app
diff --git a/src/app/document_exporter.h b/src/app/document_exporter.h
new file mode 100644
index 000000000..7ea27b881
--- /dev/null
+++ b/src/app/document_exporter.h
@@ -0,0 +1,111 @@
+/* Aseprite
+ * Copyright (C) 2001-2013  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_DOCUMENT_EXPORTER_H_INCLUDED
+#define APP_DOCUMENT_EXPORTER_H_INCLUDED
+
+#include "base/disable_copying.h"
+#include "gfx/fwd.h"
+
+#include <iosfwd>
+#include <vector>
+
+namespace raster {
+  class Image;
+}
+
+namespace app {
+  class Document;
+
+  class DocumentExporter {
+  public:
+    enum DataFormat {
+      JsonDataFormat,
+      DefaultDataFormat = JsonDataFormat
+    };
+
+    enum TextureFormat {
+      JsonTextureFormat,
+      DefaultTextureFormat = JsonTextureFormat
+    };
+
+    enum ScaleMode {
+      DefaultScaleMode
+    };
+
+    DocumentExporter() :
+      m_dataFormat(DefaultDataFormat),
+      m_textureFormat(DefaultTextureFormat),
+      m_scaleMode(DefaultScaleMode) {
+    }
+
+    void setDataFormat(DataFormat format) {
+      m_dataFormat = format;
+    }
+
+    void setDataFilename(const std::string& filename) {
+      m_dataFilename = filename;
+    }
+
+    void setTextureFormat(TextureFormat format) {
+      m_textureFormat = format;
+    }
+
+    void setTextureFilename(const std::string& filename) {
+      m_textureFilename = filename;
+    }
+
+    void setScale(double scale) {
+      m_scale = scale;
+    }
+
+    void setScaleMode(ScaleMode mode) {
+      m_scaleMode = mode;
+    }
+
+    void addDocument(Document* document) {
+      m_documents.push_back(document);
+    }
+
+    void exportSheet();
+
+  private:
+    class Sample;
+    class Samples;
+    class LayoutSamples;
+    class SimpleLayoutSamples;
+
+    void captureSamples(Samples& samples);
+    Document* createEmptyTexture(const Samples& samples);
+    void renderTexture(const Samples& samples, raster::Image* textureImage);
+    void createDataFile(const Samples& samples, std::ostream& os, raster::Image* textureImage);
+
+    DataFormat m_dataFormat;
+    std::string m_dataFilename;
+    TextureFormat m_textureFormat;
+    std::string m_textureFilename;
+    double m_scale;
+    ScaleMode m_scaleMode;
+    std::vector<Document*> m_documents;
+
+    DISABLE_COPYING(DocumentExporter);
+  };
+
+} // namespace app
+
+#endif
diff --git a/src/app/ui_context.cpp b/src/app/ui_context.cpp
index 8d555af78..18832cda4 100644
--- a/src/app/ui_context.cpp
+++ b/src/app/ui_context.cpp
@@ -134,6 +134,10 @@ void UIContext::onAddDocument(Document* document)
   // base method
   Context::onAddDocument(document);
 
+  // We don't create views in batch mode.
+  if (!App::instance()->isGui())
+    return;
+
   // Add a new view for this document
   DocumentView* view = new DocumentView(document, DocumentView::Normal);