diff --git a/ChangeLog b/ChangeLog
index 0d41dea52..2a2e0db44 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,11 +1,23 @@
 2008-10-13  David A. Capello  <davidcapello@gmail.com>
 
+	* src/raster/gfxobj.cpp (_gfxobj_set_id): Fixed (the object is
+	removed from the map before its ID is changed).
+
+	* src/raster/stock.cpp (Stock::Stock): Fixed.
+
+	* src/raster/undoable.cpp (Undoable::crop_sprite)
+	(Undoable::crop_layer, Undoable::autocrop_sprite)
+	(Undoable::replace_stock_image): Added.
+
+	* src/raster/image.cpp (image_shrink_rect): Added.
+
 	* src/raster/gfxobj.cpp (objects_map): Replaced JList 'objects'
 	by a 'objects_map' (a std::map).
 
 	* src/raster/sprite.cpp (~Sprite),
-	src/modules/palettes.cpp (exit_module_palette): Fixed a serious
-	bug where palettes were not freed right (jfree instead of
+	* src/modules/palettes.cpp (exit_module_palette):
+	* src/commands/cmd_palette_editor.cpp (load_command): Fixed a
+	serious bug where palettes were not freed right (jfree instead of
 	palette_free). It leaves dead-pointers in the collection of
 	graphics objects in 'gfxobj.cpp'.
 
diff --git a/NEWS.txt b/NEWS.txt
index 36d076acb..996a37d03 100644
--- a/NEWS.txt
+++ b/NEWS.txt
@@ -11,7 +11,8 @@ NEWS
 + Added support to lock lines in special angles with the Shift key,
   useful to draw in isometric views (feature request #1961397).
 + Fixed bugs #1958760 and #1958932.
-+ Fixed other bugs (Flatten Layers, File Selector, etc.).
++ Fixed other serious bugs (Dead-pointers to palettes, Flatten
+  Layers, File Selector, etc.).
 
 0.6b2
 -----
diff --git a/src/commands/cmd_crop.cpp b/src/commands/cmd_crop.cpp
index 9173d99b5..0143c308e 100644
--- a/src/commands/cmd_crop.cpp
+++ b/src/commands/cmd_crop.cpp
@@ -19,13 +19,15 @@
 #include "config.h"
 
 #include "commands/commands.h"
+#include "core/app.h"
 #include "modules/gui.h"
 #include "modules/sprites.h"
 #include "raster/image.h"
 #include "raster/layer.h"
 #include "raster/mask.h"
 #include "raster/sprite.h"
-#include "raster/undo.h"
+#include "raster/undoable.h"
+#include "widgets/colbar.h"
 #include "util/autocrop.h"
 #include "util/functions.h"
 #include "util/misc.h"
@@ -45,11 +47,16 @@ static bool cmd_crop_sprite_enabled(const char *argument)
 static void cmd_crop_sprite_execute(const char *argument)
 {
   Sprite *sprite = current_sprite;
-
-  if (undo_is_enabled(sprite->undo))
-    undo_set_label(sprite->undo, "Sprite Crop");
-
-  CropSprite(sprite);
+  {
+    Undoable undoable(sprite, "Sprite Crop");
+    undoable.crop_sprite(current_sprite->mask->x,
+			 current_sprite->mask->y,
+			 current_sprite->mask->w,
+			 current_sprite->mask->h,
+			 colorbar_get_bg_color(app_get_colorbar()));
+    undoable.commit();
+  }
+  sprite_generate_mask_boundaries(sprite);
   update_screen_for_sprite(sprite);
 }
 
@@ -65,11 +72,12 @@ static bool cmd_autocrop_sprite_enabled(const char *argument)
 static void cmd_autocrop_sprite_execute(const char *argument)
 {
   Sprite *sprite = current_sprite;
-
-  if (undo_is_enabled(sprite->undo))
-    undo_set_label(sprite->undo, "Sprite Autocrop");
-
-  autocrop_sprite(sprite);
+  {
+    Undoable undoable(sprite, "Sprite Autocrop");
+    undoable.autocrop_sprite(colorbar_get_bg_color(app_get_colorbar()));
+    undoable.commit();
+  }
+  sprite_generate_mask_boundaries(sprite);
   update_screen_for_sprite(sprite);
 }
 
diff --git a/src/commands/cmd_duplicate_sprite.cpp b/src/commands/cmd_duplicate_sprite.cpp
index 616acfe38..439d52702 100644
--- a/src/commands/cmd_duplicate_sprite.cpp
+++ b/src/commands/cmd_duplicate_sprite.cpp
@@ -38,7 +38,6 @@ static void cmd_duplicate_sprite_execute(const char *argument)
 {
   JWidget window, src_name, dst_name, flatten;
   Sprite *sprite = current_sprite;
-  Sprite *sprite_copy;
   char buf[1024];
 
   /* load the window widget */
@@ -64,7 +63,9 @@ static void cmd_duplicate_sprite_execute(const char *argument)
   if (jwindow_get_killer(window) == jwidget_find_name(window, "ok")) {
     set_config_bool("DuplicateSprite", "Flatten",
 		    jwidget_is_selected(flatten));
-    
+
+    // make a copy of the current sprite
+    Sprite *sprite_copy;
     if (jwidget_is_selected(flatten))
       sprite_copy = sprite_new_flatten_copy(sprite);
     else
diff --git a/src/commands/cmd_palette_editor.cpp b/src/commands/cmd_palette_editor.cpp
index 08b4bbef3..28bd463e1 100644
--- a/src/commands/cmd_palette_editor.cpp
+++ b/src/commands/cmd_palette_editor.cpp
@@ -292,7 +292,7 @@ static void load_command(JWidget widget)
     }
     else {
       set_new_palette(palette);
-      jfree(palette);
+      palette_free(palette);
     }
   }
 }
diff --git a/src/core/app.cpp b/src/core/app.cpp
index ff2383152..53c0aa3b2 100644
--- a/src/core/app.cpp
+++ b/src/core/app.cpp
@@ -711,15 +711,15 @@ static Option *option_new(int type, const char *data)
   return option;
 }
 
-static void option_free(Option *option)
+static void option_free(Option* option)
 {
   jfree(option->data);
   jfree(option);
 }
 
-static AppHook *apphook_new(void (*proc)(void *), void *data)
+static AppHook *apphook_new(void (*proc)(void*), void* data)
 {
-  AppHook *apphook = jnew(AppHook, 1);
+  AppHook* apphook = jnew(AppHook, 1);
   if (!apphook)
     return NULL;
 
diff --git a/src/dialogs/aniedit.cpp b/src/dialogs/aniedit.cpp
index ab6e8c456..4f17dc82d 100644
--- a/src/dialogs/aniedit.cpp
+++ b/src/dialogs/aniedit.cpp
@@ -243,7 +243,7 @@ static bool anieditor_msg_proc(JWidget widget, JMessage msg)
   switch (msg->type) {
 
     case JM_DESTROY:
-      if (anieditor->layers != NULL)
+      if (anieditor->layers)
 	jfree(anieditor->layers);
       jfree(anieditor);
       break;
diff --git a/src/modules/gfx.cpp b/src/modules/gfx.cpp
index 64e6705fa..f1c50a454 100644
--- a/src/modules/gfx.cpp
+++ b/src/modules/gfx.cpp
@@ -248,16 +248,16 @@ void simple_dotted_mode(BITMAP *bmp, int fg, int bg)
 /**********************************************************************/
 /* Set/Restore sub-clip regions */
 
-typedef struct CLIP_DATA
+struct CLIP_DATA
 {
-  BITMAP *bmp;
+  BITMAP* bmp;
   int cl, ct, cr, cb;
-} CLIP_DATA;
+};
 
-void *subclip(BITMAP *bmp, int x1, int y1, int x2, int y2)
+void* subclip(BITMAP* bmp, int x1, int y1, int x2, int y2)
 {
   int cl, ct, cr, cb;
-  CLIP_DATA *data;
+  CLIP_DATA* data;
 
   cl = bmp->cl;
   ct = bmp->ct;
@@ -274,7 +274,7 @@ void *subclip(BITMAP *bmp, int x1, int y1, int x2, int y2)
 
   set_clip(bmp, x1, y1, x2, y2);
 
-  data = jnew(CLIP_DATA, 1);
+  data = new CLIP_DATA;
   data->bmp = bmp;
   data->cl = cl;
   data->ct = ct;
@@ -284,11 +284,11 @@ void *subclip(BITMAP *bmp, int x1, int y1, int x2, int y2)
   return data;
 }
 
-void backclip(void *_data)
+void backclip(void* _data)
 {
   CLIP_DATA* data = reinterpret_cast<CLIP_DATA*>(_data);
   set_clip(data->bmp, data->cl, data->ct, data->cr, data->cb);
-  jfree(data);
+  delete data;
 }
 
 /**********************************************************************/
@@ -302,8 +302,8 @@ struct RectTracker
   int *pixel;
 };
 
-static void do_rect(BITMAP *bmp, int x1, int y1, int x2, int y2, int c,
-		    void (*proc)(BITMAP *bmp, int x, int y, int c))
+static void do_rect(BITMAP* bmp, int x1, int y1, int x2, int y2, int c,
+		    void (*proc)(BITMAP* bmp, int x, int y, int c))
 {
   int x, y, u1, u2, v1, v2;
 
@@ -338,25 +338,25 @@ static void do_rect(BITMAP *bmp, int x1, int y1, int x2, int y2, int c,
   }
 }
 
-static void count_rect(BITMAP *bmp, int x, int y, int c)
+static void count_rect(BITMAP* bmp, int x, int y, int c)
 {
-  RectTracker *data = (RectTracker *)c;
+  RectTracker* data = (RectTracker*)c;
   data->npixel++;
 }
 
-static void save_rect(BITMAP *bmp, int x, int y, int c)
+static void save_rect(BITMAP* bmp, int x, int y, int c)
 {
-  RectTracker *data = (RectTracker *)c;
+  RectTracker* data = (RectTracker*)c;
   data->pixel[data->npixel++] = getpixel(bmp, x, y);
 }
 
-static void restore_rect(BITMAP *bmp, int x, int y, int c)
+static void restore_rect(BITMAP* bmp, int x, int y, int c)
 {
-  RectTracker *data = (RectTracker *)c;
+  RectTracker* data = (RectTracker*)c;
   putpixel(bmp, x, y, data->pixel[data->npixel++]);
 }
 
-RectTracker *rect_tracker_new(BITMAP *bmp, int x1, int y1, int x2, int y2)
+RectTracker* rect_tracker_new(BITMAP* bmp, int x1, int y1, int x2, int y2)
 {
   RectTracker *data;
   int x, y;
@@ -366,7 +366,7 @@ RectTracker *rect_tracker_new(BITMAP *bmp, int x1, int y1, int x2, int y2)
   if (x1 > x2) { x = x1; x1 = x2; x2 = x; }
   if (y1 > y2) { y = y1; y1 = y2; y2 = y; }
 
-  data = jnew(RectTracker, 1);
+  data = new RectTracker;
 
   data->bmp = bmp;
   data->x1 = x1;
@@ -378,7 +378,7 @@ RectTracker *rect_tracker_new(BITMAP *bmp, int x1, int y1, int x2, int y2)
   do_rect(bmp, x1, y1, x2, y2, (int)data, count_rect);
 
   if (data->npixel > 0)
-    data->pixel = (int*)jmalloc(sizeof(int) * data->npixel);
+    data->pixel = new int[data->npixel];
   else
     data->pixel = NULL;
 
@@ -390,7 +390,7 @@ RectTracker *rect_tracker_new(BITMAP *bmp, int x1, int y1, int x2, int y2)
   return data;
 }
 
-void rect_tracker_free(RectTracker *data)
+void rect_tracker_free(RectTracker* data)
 {
   jmouse_hide();
 
@@ -398,9 +398,8 @@ void rect_tracker_free(RectTracker *data)
   do_rect(data->bmp, data->x1, data->y1, data->x2, data->y2,
 	  (int)data, restore_rect);
 
-  if (data->pixel != NULL)
-    jfree(data->pixel);
-  jfree(data);
+  delete[] data->pixel;
+  delete data;
 
   jmouse_show();
 }
diff --git a/src/modules/sprites.cpp b/src/modules/sprites.cpp
index 186889689..cb90e0ef4 100644
--- a/src/modules/sprites.cpp
+++ b/src/modules/sprites.cpp
@@ -225,7 +225,7 @@ ImageRef *images_ref_get_from_sprite(Sprite* sprite, int target, bool write)
   return images_ref_get_from_layer(sprite, layer, target, write);
 }
 
-void images_ref_free(ImageRef *image_ref)
+void images_ref_free(ImageRef* image_ref)
 {
   ImageRef *p, *next;
 
diff --git a/src/raster/gfxobj.cpp b/src/raster/gfxobj.cpp
index da9f77a6c..51cae83a0 100644
--- a/src/raster/gfxobj.cpp
+++ b/src/raster/gfxobj.cpp
@@ -32,6 +32,9 @@ static JMutex objects_mutex;
 static gfxobj_id object_id = 0;		         // last object ID created
 static std::map<gfxobj_id, GfxObj*> objects_map; // graphics objects map
 
+static void insert_gfxobj(GfxObj* gfxobj);
+static void erase_gfxobj(GfxObj* gfxobj);
+
 //////////////////////////////////////////////////////////////////////
 
 bool gfxobj_init()
@@ -46,7 +49,6 @@ bool gfxobj_init()
 void gfxobj_exit()
 {
   assert(objects_map.empty());
-
   jmutex_free(objects_mutex);
 }
 
@@ -69,14 +71,7 @@ GfxObj::~GfxObj()
 {
   // we have to remove this object from the map
   jmutex_lock(objects_mutex);
-  {
-    std::map<gfxobj_id, GfxObj*>::iterator
-      it = objects_map.find(this->id);
-
-    assert(it != objects_map.end());
-
-    objects_map.erase(it);
-  }
+  erase_gfxobj(this);
   jmutex_unlock(objects_mutex);
 }
 
@@ -88,7 +83,7 @@ void GfxObj::assign_id()
     this->id = ++object_id;
 
     // and here we add the object in the map of graphics-objects
-    objects_map.insert(std::make_pair(this->id, this));
+    insert_gfxobj(this);
   }
   jmutex_unlock(objects_mutex);
 }
@@ -115,7 +110,29 @@ GfxObj* gfxobj_find(gfxobj_id id)
 
 void _gfxobj_set_id(GfxObj* gfxobj, gfxobj_id id)
 {
+  assert(gfxobj_find(gfxobj->id) == gfxobj);
   assert(gfxobj_find(id) == NULL);
 
-  gfxobj->id = id;
+  jmutex_lock(objects_mutex);
+  erase_gfxobj(gfxobj);		// remove the object
+  gfxobj->id = id;		// change the ID
+  insert_gfxobj(gfxobj);	// insert the object again in the map
+  jmutex_unlock(objects_mutex);
+}
+
+//////////////////////////////////////////////////////////////////////
+
+static void insert_gfxobj(GfxObj* gfxobj)
+{
+  objects_map.insert(std::make_pair(gfxobj->id, gfxobj));
+}
+
+static void erase_gfxobj(GfxObj* gfxobj)
+{
+  std::map<gfxobj_id, GfxObj*>::iterator
+    it = objects_map.find(gfxobj->id);
+  
+  assert(it != objects_map.end());
+
+  objects_map.erase(it);
 }
diff --git a/src/raster/image.cpp b/src/raster/image.cpp
index 36eaa4340..aeffcccf4 100644
--- a/src/raster/image.cpp
+++ b/src/raster/image.cpp
@@ -545,3 +545,47 @@ int image_count_diff(const Image* i1, const Image* i2)
   return diff;
 }
 
+bool image_shrink_rect(Image *image, int *x1, int *y1, int *x2, int *y2, int refpixel)
+{
+#define SHRINK_SIDE(u_begin, u_op, u_final, u_add,		\
+		    v_begin, v_op, v_final, v_add, U, V, var)	\
+  do {								\
+    for (u = u_begin; u u_op u_final; u u_add) {		\
+      for (v = v_begin; v v_op v_final; v v_add) {		\
+	if (image->method->getpixel (image, U, V) != refpixel)	\
+	  break;						\
+      }								\
+      if (v == v_final)						\
+	var;							\
+      else							\
+	break;							\
+    }								\
+  } while (0)
+
+  int u, v;
+
+  *x1 = 0;
+  *y1 = 0;
+  *x2 = image->w-1;
+  *y2 = image->h-1;
+
+  SHRINK_SIDE(0, <, image->w, ++,
+	      0, <, image->h, ++, u, v, (*x1)++);
+
+  SHRINK_SIDE(0, <, image->h, ++,
+	      0, <, image->w, ++, v, u, (*y1)++);
+
+  SHRINK_SIDE(image->w-1, >, 0, --,
+	      0, <, image->h, ++, u, v, (*x2)--);
+
+  SHRINK_SIDE(image->h-1, >, 0, --,
+	      0, <, image->w, ++, v, u, (*y2)--);
+
+  if ((*x1 > *x2) || (*y1 > *y2))
+    return false;
+  else
+    return true;
+
+#undef SHRINK_SIDE
+}
+
diff --git a/src/raster/image.h b/src/raster/image.h
index 866bd495f..07d36f63c 100644
--- a/src/raster/image.h
+++ b/src/raster/image.h
@@ -138,5 +138,6 @@ void image_to_allegro(Image* image, BITMAP* bmp, int x, int y);
 
 void image_convert(Image* dst, const Image* src);
 int image_count_diff(const Image* i1, const Image* i2);
+bool image_shrink_rect(Image *image, int *x1, int *y1, int *x2, int *y2, int refpixel);
 
 #endif				/* RASTER_IMAGE_H */
diff --git a/src/raster/sprite.cpp b/src/raster/sprite.cpp
index 56e0ac5b1..fd50bbf4e 100644
--- a/src/raster/sprite.cpp
+++ b/src/raster/sprite.cpp
@@ -446,6 +446,9 @@ void sprite_set_format_options(Sprite* sprite, struct FormatOptions *format_opti
 
 void sprite_set_size(Sprite* sprite, int w, int h)
 {
+  assert(w > 0);
+  assert(h > 0);
+
   sprite->w = w;
   sprite->h = h;
 }
diff --git a/src/raster/stock.cpp b/src/raster/stock.cpp
index 17eb660fe..c0dc1dd7c 100644
--- a/src/raster/stock.cpp
+++ b/src/raster/stock.cpp
@@ -41,8 +41,10 @@ Stock::Stock(const Stock& stock)
   : GfxObj(stock)
 {
   this->imgtype = stock.imgtype;
+  this->nimage = 0;
+  this->image = NULL;
 
-  for (int c=this->nimage; c<stock.nimage; ++c) {
+  for (int c=0; c<stock.nimage; ++c) {
     if (!stock.image[c])
       stock_add_image(this, NULL);
     else {
@@ -58,7 +60,7 @@ Stock::Stock(const Stock& stock)
 Stock::~Stock()
 {
   for (int i=0; i<this->nimage; i++) {
-    if (this->image[i] != NULL)
+    if (this->image[i])
       image_free(this->image[i]);
   }
   jfree(this->image);
diff --git a/src/raster/undo.cpp b/src/raster/undo.cpp
index 4b0ea3b37..4f2a6c5ea 100644
--- a/src/raster/undo.cpp
+++ b/src/raster/undo.cpp
@@ -627,7 +627,6 @@ static void chunk_image_new(UndoStream* stream, Image* image, int x, int y, int
   chunk->y = y;
   chunk->w = w;
   chunk->h = h;
-/*   chunk->data = jmalloc(size*h); */
 
   ptr = chunk->data;
   for (v=0; v<h; ++v) {
@@ -636,11 +635,6 @@ static void chunk_image_new(UndoStream* stream, Image* image, int x, int y, int
   }
 }
 
-/* static void chunk_image_free(UndoChunkImage* chunk) */
-/* { */
-/*   jfree(chunk->data); */
-/* } */
-
 static void chunk_image_invert(UndoStream* stream, UndoChunkImage* chunk, int state)
 {
   unsigned int id = chunk->image_id;
@@ -914,7 +908,7 @@ void undo_replace_image(Undo* undo, Stock *stock, int image_index)
 
 static void chunk_replace_image_new(UndoStream* stream, Stock *stock, int image_index)
 {
-  Image* image = stock->image[image_index];
+  Image* image = stock_get_image(stock, image_index);
   UndoChunkReplaceImage* chunk = (UndoChunkReplaceImage* )
     undo_chunk_new(stream,
 		   UNDO_TYPE_REPLACE_IMAGE,
@@ -930,17 +924,21 @@ static void chunk_replace_image_invert(UndoStream* stream, UndoChunkReplaceImage
 {
   unsigned long stock_id = chunk->stock_id;
   unsigned long image_index = chunk->image_index;
-  Stock *stock = (Stock *)gfxobj_find(stock_id);
+  Stock* stock = (Stock*)gfxobj_find(stock_id);
 
   if (stock) {
+    // read the image to be restored from the chunk
     Image* image = read_raw_image(chunk->data);
 
+    // save the current image in the (redo) stream
     chunk_replace_image_new(stream, stock, image_index);
+    Image* old_image = stock_get_image(stock, image_index);
 
-    if (stock->image[image_index])
-      image_free(stock->image[image_index]);
-
+    // replace the image in the stock
     stock_replace_image(stock, image_index, image);
+
+    // destroy the old image
+    image_free(old_image);
   }
 }
 
diff --git a/src/raster/undoable.cpp b/src/raster/undoable.cpp
index 46ac9acd0..f7e9363b1 100644
--- a/src/raster/undoable.cpp
+++ b/src/raster/undoable.cpp
@@ -118,6 +118,69 @@ void Undoable::set_current_layer(Layer* layer)
   sprite_set_layer(sprite, layer);
 }
 
+void Undoable::set_sprite_size(int w, int h)
+{
+  assert(w > 0);
+  assert(h > 0);
+
+  if (is_enabled()) {
+    undo_int(sprite->undo, sprite, &sprite->w);
+    undo_int(sprite->undo, sprite, &sprite->h);
+  }
+
+  sprite_set_size(sprite, w, h);
+}
+
+void Undoable::crop_sprite(int x, int y, int w, int h, int bgcolor)
+{
+  set_sprite_size(w, h);
+
+  displace_layers(sprite->set, -x, -y);
+
+  Layer *background_layer = sprite_get_background_layer(sprite);
+  if (background_layer)
+    crop_layer(background_layer, 0, 0, sprite->w, sprite->h, bgcolor);
+
+  if (!mask_is_empty(sprite->mask))
+    set_mask_position(sprite->mask->x-x, sprite->mask->y-y);
+}
+
+void Undoable::autocrop_sprite(int bgcolor)
+{
+  int old_frame = sprite->frame;
+  int x1, y1, x2, y2;
+  int u1, v1, u2, v2;
+
+  x1 = y1 = INT_MAX;
+  x2 = y2 = INT_MIN;
+
+  Image* image = image_new(sprite->imgtype, sprite->w, sprite->h);
+
+  for (sprite->frame=0; sprite->frame<sprite->frames; sprite->frame++) {
+    image_clear(image, 0);
+    sprite_render(sprite, image, 0, 0);
+
+    // TODO configurable (what color pixel to use as "refpixel",
+    // here we are using the top-left pixel by default)
+    if (image_shrink_rect(image, &u1, &v1, &u2, &v2,
+			  image_getpixel(image, 0, 0))) {
+      x1 = MIN(x1, u1);
+      y1 = MIN(y1, v1);
+      x2 = MAX(x2, u2);
+      y2 = MAX(y2, v2);
+    }
+  }
+  sprite->frame = old_frame;
+
+  image_free(image);
+
+  // do nothing
+  if (x1 > x2 || y1 > y2)
+    return;
+
+  crop_sprite(x1, y1, x2-x1+1, y2-y1+1, bgcolor);
+}
+
 /**
  * Adds a new image in the stock.
  *
@@ -154,6 +217,22 @@ void Undoable::remove_image_from_stock(int image_index)
   image_free(image);
 }
 
+void Undoable::replace_stock_image(int image_index, Image* new_image)
+{
+  // get the current image in the 'image_index' position
+  Image* old_image = stock_get_image(sprite->stock, image_index);
+  assert(old_image);
+
+  // replace the image in the stock
+  if (is_enabled())
+    undo_replace_image(sprite->undo, sprite->stock, image_index);
+
+  stock_replace_image(sprite->stock, image_index, new_image);
+
+  // destroy the old image
+  image_free(old_image);
+}
+
 /**
  * Creates a new transparent layer.
  */
@@ -221,6 +300,47 @@ void Undoable::move_layer_after(Layer* layer, Layer* after_this)
   layer_move_layer(layer->parent_layer, layer, after_this);
 }
 
+void Undoable::crop_layer(Layer* layer, int x, int y, int w, int h, int bgcolor)
+{
+  JLink link;
+
+  if (!layer_is_background(layer))
+    bgcolor = 0;
+
+  JI_LIST_FOR_EACH(layer->cels, link) {
+    Cel* cel = reinterpret_cast<Cel*>(link->data);
+    crop_cel(cel, x, y, w, h, bgcolor);
+  }
+}
+
+/**
+ * Moves every frame in @a layer with the offset (@a dx, @a dy).
+ */
+void Undoable::displace_layers(Layer* layer, int dx, int dy)
+{
+  switch (layer->type) {
+
+    case GFXOBJ_LAYER_IMAGE: {
+      Cel* cel;
+      JLink link;
+
+      JI_LIST_FOR_EACH(layer->cels, link) {
+	cel = reinterpret_cast<Cel*>(link->data);
+	set_cel_position(cel, cel->x+dx, cel->y+dy);
+      }
+      break;
+    }
+
+    case GFXOBJ_LAYER_SET: {
+      JLink link;
+      JI_LIST_FOR_EACH(layer->layers, link)
+	displace_layers(reinterpret_cast<Layer*>(link->data), dx, dy);
+      break;
+    }
+
+  }
+}
+
 void Undoable::new_frame()
 {
   // add a new cel to every layer
@@ -399,6 +519,19 @@ void Undoable::set_cel_frame_position(Cel* cel, int frame)
   cel->frame = frame;
 }
 
+void Undoable::set_cel_position(Cel* cel, int x, int y)
+{
+  assert(cel);
+
+  if (is_enabled()) {
+    undo_int(sprite->undo, cel, &cel->x);
+    undo_int(sprite->undo, cel, &cel->y);
+  }
+
+  cel->x = x;
+  cel->y = y;
+}
+
 void Undoable::set_frame_duration(int frame, int msecs)
 {
   if (is_enabled())
@@ -509,6 +642,21 @@ Cel* Undoable::get_current_cel()
     return NULL;
 }
 
+void Undoable::crop_cel(Cel* cel, int x, int y, int w, int h, int bgcolor)
+{
+  Image* cel_image = stock_get_image(sprite->stock, cel->image);
+  assert(cel_image);
+    
+  // create the new image through a crop
+  Image* new_image = image_crop(cel_image, x-cel->x, y-cel->y, w, h, bgcolor);
+
+  // replace the image in the stock that is pointed by the cel
+  replace_stock_image(cel->image, new_image);
+
+  // update the cel's position
+  set_cel_position(cel, x, y);
+}
+
 Image* Undoable::get_cel_image(Cel* cel)
 {
   if (cel && cel->image >= 0 && cel->image < sprite->stock->nimage)
@@ -577,3 +725,27 @@ void Undoable::clear_mask(int bgcolor)
   }
 }
 
+void Undoable::copy_to_current_mask(Mask* mask)
+{
+  assert(sprite->mask);
+  assert(mask);
+
+  if (is_enabled())
+    undo_set_mask(sprite->undo, sprite);
+
+  mask_copy(sprite->mask, mask);
+}
+
+void Undoable::set_mask_position(int x, int y)
+{
+  assert(sprite->mask);
+
+  if (is_enabled()) {
+    undo_int(sprite->undo, sprite->mask, &sprite->mask->x);
+    undo_int(sprite->undo, sprite->mask, &sprite->mask->y);
+  }
+
+  sprite->mask->x = x;
+  sprite->mask->y = y;
+}
+
diff --git a/src/raster/undoable.h b/src/raster/undoable.h
index 2f0581d6d..889960f51 100644
--- a/src/raster/undoable.h
+++ b/src/raster/undoable.h
@@ -47,15 +47,21 @@ public:
   void set_number_of_frames(int frames);
   void set_current_frame(int frame);
   void set_current_layer(Layer* layer);
+  void set_sprite_size(int w, int h);
+  void crop_sprite(int x, int y, int w, int h, int bgcolor);
+  void autocrop_sprite(int bgcolor);
 
   // for images in stock
   int add_image_in_stock(Image* image);
   void remove_image_from_stock(int image_index);
+  void replace_stock_image(int image_index, Image* new_image);
 
   // for layers
   Layer* new_layer();
   void remove_layer(Layer* layer);
   void move_layer_after(Layer *layer, Layer *after_this);
+  void crop_layer(Layer* layer, int x, int y, int w, int h, int bgcolor);
+  void displace_layers(Layer* layer, int dx, int dy);
 
   // for frames
   void new_frame();
@@ -72,12 +78,18 @@ public:
   void add_cel(Layer* layer, Cel* cel);
   void remove_cel(Layer* layer, Cel* cel);
   void set_cel_frame_position(Cel* cel, int frame);
+  void set_cel_position(Cel* cel, int x, int y);
   Cel* get_current_cel();
+  void crop_cel(Cel* cel, int x, int y, int w, int h, int bgcolor);
 
   // for image
   Image* get_cel_image(Cel* cel);
   void clear_mask(int bgcolor);
 
+  // for mask
+  void copy_to_current_mask(Mask* mask);
+  void set_mask_position(int x, int y);
+
 };
 
 #endif /* RASTER_UNDOABLE_H */
diff --git a/src/util/autocrop.cpp b/src/util/autocrop.cpp
index 32dca1758..b727b491d 100644
--- a/src/util/autocrop.cpp
+++ b/src/util/autocrop.cpp
@@ -24,56 +24,6 @@
 #include "util/autocrop.h"
 #include "util/functions.h"
 
-void autocrop_sprite(Sprite *sprite)
-{
-  if (sprite != NULL) {
-    int old_frame = sprite->frame;
-    Mask *old_mask = sprite->mask;
-    Mask *mask;
-    Image *image;
-    int x1, y1, x2, y2;
-    int u1, v1, u2, v2;
-
-    x1 = y1 = INT_MAX;
-    x2 = y2 = INT_MIN;
-
-    image = image_new(sprite->imgtype, sprite->w, sprite->h);
-    if (!image)
-      return;
-
-    for (sprite->frame=0; sprite->frame<sprite->frames; sprite->frame++) {
-      image_clear(image, 0);
-      sprite_render(sprite, image, 0, 0);
-
-      /* TODO configurable (what color pixel to use as "refpixel",
-	 here we are using the top-left pixel by default) */
-      if (get_shrink_rect(&u1, &v1, &u2, &v2,
-			  image, image_getpixel (image, 0, 0))) {
-	x1 = MIN(x1, u1);
-	y1 = MIN(y1, v1);
-	x2 = MAX(x2, u2);
-	y2 = MAX(y2, v2);
-      }
-    }
-    sprite->frame = old_frame;
-
-    image_free(image);
-
-    /* do nothing */
-    if (x1 > x2 || y1 > y2)
-      return;
-
-    mask = mask_new();
-    mask_replace(mask, x1, y1, x2-x1+1, y2-y1+1);
-
-    sprite->mask = mask;
-    CropSprite(sprite);
-
-    sprite->mask = old_mask;
-    sprite_generate_mask_boundaries(sprite);
-  }
-}
-
 bool get_shrink_rect(int *x1, int *y1, int *x2, int *y2,
 		     Image *image, int refpixel)
 {
diff --git a/src/util/autocrop.h b/src/util/autocrop.h
index c1adb63fc..4ae1ef06a 100644
--- a/src/util/autocrop.h
+++ b/src/util/autocrop.h
@@ -19,8 +19,6 @@
 #ifndef UTIL_AUTOCROP_H
 #define UTIL_AUTOCROP_H
 
-void autocrop_sprite(Sprite *sprite);
-
 bool get_shrink_rect(int *x1, int *y1, int *x2, int *y2,
 		     Image *image, int refpixel);
 bool get_shrink_rect2(int *x1, int *y1, int *x2, int *y2,
diff --git a/src/util/functions.cpp b/src/util/functions.cpp
index fe40f6185..eab8b6fb9 100644
--- a/src/util/functions.cpp
+++ b/src/util/functions.cpp
@@ -35,8 +35,6 @@
 /* Sprite                                                            */
 /*===================================================================*/
 
-static void displace_layers(Undo *undo, Layer *layer, int x, int y);
-
 /**
  * Creates a new sprite with the given dimension with one transparent
  * layer called "Layer 1".
@@ -142,78 +140,6 @@ void SetSprite(Sprite *sprite)
   set_current_sprite(sprite);
 }
 
-void CropSprite(Sprite *sprite)
-{
-  if ((sprite != NULL) &&
-      (!mask_is_empty(sprite->mask))) {
-    if (undo_is_enabled(sprite->undo)) {
-      undo_open(sprite->undo);
-      undo_int(sprite->undo, (GfxObj *)sprite, &sprite->w);
-      undo_int(sprite->undo, (GfxObj *)sprite, &sprite->h);
-    }
-
-    sprite_set_size(sprite, sprite->mask->w, sprite->mask->h);
-
-    displace_layers(sprite->undo, sprite->set,
-		    -sprite->mask->x, -sprite->mask->y);
-
-    {
-      Layer *background_layer = sprite_get_background_layer(sprite);
-      if (background_layer != NULL) {
-	CropLayer(background_layer, 0, 0, sprite->w, sprite->h);
-      }
-    }
-
-    if (undo_is_enabled(sprite->undo)) {
-      undo_int(sprite->undo, (GfxObj *)sprite->mask, &sprite->mask->x);
-      undo_int(sprite->undo, (GfxObj *)sprite->mask, &sprite->mask->y);
-    }
-
-    sprite->mask->x = 0;
-    sprite->mask->y = 0;
-
-    if (undo_is_enabled(sprite->undo))
-      undo_close(sprite->undo);
-
-    sprite_generate_mask_boundaries(sprite);
-  }
-}
-
-/**
- * Moves every frame in "layer" with the offset "x"/"y".
- */
-static void displace_layers(Undo *undo, Layer *layer, int x, int y)
-{
-  switch (layer->type) {
-
-    case GFXOBJ_LAYER_IMAGE: {
-      Cel *cel;
-      JLink link;
-
-      JI_LIST_FOR_EACH(layer->cels, link) {
-	cel = reinterpret_cast<Cel*>(link->data);
-
-	if (undo_is_enabled(undo)) {
-	  undo_int(undo, (GfxObj *)cel, &cel->x);
-	  undo_int(undo, (GfxObj *)cel, &cel->y);
-	}
-
-	cel->x += x;
-	cel->y += y;
-      }
-      break;
-    }
-
-    case GFXOBJ_LAYER_SET: {
-      JLink link;
-      JI_LIST_FOR_EACH(layer->layers, link)
-	displace_layers(undo, reinterpret_cast<Layer*>(link->data), x, y);
-      break;
-    }
-
-  }
-}
-
 /*===================================================================*/
 /* Layer                                                             */
 /*===================================================================*/
@@ -391,41 +317,6 @@ Layer *FlattenLayers(Sprite *sprite)
   return background;
 }
 
-void CropLayer(Layer *layer, int x, int y, int w, int h)
-{
-  Sprite *sprite = layer->sprite;
-  Cel *cel;
-  Image *image;
-  Image *new_image;
-  JLink link;
-
-  JI_LIST_FOR_EACH(layer->cels, link) {
-    cel = reinterpret_cast<Cel*>(link->data);
-    image = stock_get_image(sprite->stock, cel->image);
-    if (image == NULL)
-      continue;
-
-    new_image = image_crop(image, x-cel->x, y-cel->y, w, h,
-			   app_get_color_to_clear_layer(layer));
-    if (new_image == NULL) {
-      console_printf(_("Not enough memory\n"));
-      return;
-    }
-
-    if (undo_is_enabled(sprite->undo)) {
-      undo_replace_image(sprite->undo, sprite->stock, cel->image);
-      undo_int(sprite->undo, (GfxObj *)cel, &cel->x);
-      undo_int(sprite->undo, (GfxObj *)cel, &cel->y);
-    }
-
-    cel->x = x;
-    cel->y = y;
-
-    stock_replace_image(sprite->stock, cel->image, new_image);
-    image_free(image);
-  }
-}
-
 /**
  * Converts the selected layer in a `Background' layer.
  */
@@ -667,38 +558,3 @@ void RemoveCel(Layer *layer, Cel *cel)
     cel_free(cel);
   }
 }
-
-void CropCel()
-{
-  Sprite *sprite = current_sprite;
-  Image *image = GetImage(current_sprite);
-
-  if ((sprite) && (!mask_is_empty (sprite->mask)) && (image)) {
-    Cel *cel = layer_get_cel(sprite->layer, sprite->frame);
-
-    /* undo */
-    if (undo_is_enabled(sprite->undo)) {
-      undo_open(sprite->undo);
-      undo_int(sprite->undo, (GfxObj *)cel, &cel->x);
-      undo_int(sprite->undo, (GfxObj *)cel, &cel->y);
-      undo_replace_image(sprite->undo, sprite->stock, cel->image);
-      undo_close(sprite->undo);
-    }
-
-    /* replace the image */
-    sprite->stock->image[cel->image] =
-      image_crop(image,
-		 sprite->mask->x-cel->x,
-		 sprite->mask->y-cel->y,
-		 sprite->mask->w,
-		 sprite->mask->h, 0);
-
-    image_free(image);		/* destroy the old image */
-
-    /* change the cel position */
-    cel->x = sprite->mask->x;
-    cel->y = sprite->mask->y;
-
-    update_screen_for_sprite(sprite);
-  }
-}
diff --git a/src/util/functions.h b/src/util/functions.h
index e09897b6b..eb72df6b8 100644
--- a/src/util/functions.h
+++ b/src/util/functions.h
@@ -33,8 +33,6 @@ void SaveSprite(const char* filename);
 
 void SetSprite(Sprite* sprite); 
 
-void CropSprite(Sprite* sprite);
-
 /*===================================================================*/
 /* Layer                                                             */
 /*===================================================================*/
@@ -45,8 +43,6 @@ char *GetUniqueLayerName(Sprite* sprite);
 
 Layer* FlattenLayers(Sprite* sprite);
 
-void CropLayer(Layer* layer, int x, int y, int w, int h);
-
 void BackgroundFromLayer(Sprite* sprite);
 void LayerFromBackground(Sprite* sprite);
 
@@ -56,6 +52,4 @@ void LayerFromBackground(Sprite* sprite);
 
 void RemoveCel(Layer* layer, Cel* cel);
 
-void CropCel();
-
 #endif /* UTIL_FUNCTIONS_H */