Cel ID is available again in onBefore/AfterRemoveCel() notifications

We have added a CelData reference counter (CelData::m_refs) to known
how many cels are referencing/linked with the same CelData in the
sprite. It makes the Cel::links() member function impl a lot simpler:
without the need to access the parent layer to iterate all cels to
count all links.

laf

@@ -1 +1 @@
-Subproject commit de781a5066732d700ac4520ee5fc9034e92875ad
+Subproject commit 39706c11063fb53cf4c8e865102c6f71e2606906

src/app/cmd/add_cel.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2020  Igara Studio S.A.
+// Copyright (C) 2020-2025  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -15,11 +15,7 @@
 #include "app/doc_event.h"
 #include "base/serialization.h"
 #include "doc/cel.h"
-#include "doc/cel_data_io.h"
-#include "doc/cel_io.h"
-#include "doc/image_io.h"
 #include "doc/layer.h"
-#include "doc/subobjects_io.h"
 
 namespace app { namespace cmd {
 
@@ -27,7 +23,7 @@ using namespace base::serialization;
 using namespace base::serialization::little_endian;
 using namespace doc;
 
-AddCel::AddCel(Layer* layer, Cel* cel) : WithLayer(layer), WithCel(cel), m_size(0)
+AddCel::AddCel(Layer* layer, Cel* cel) : WithLayer(layer), WithCel(cel)
 {
 }
 
@@ -48,41 +44,20 @@ void AddCel::onUndo()
   ASSERT(layer);
   ASSERT(cel);
 
-  // Save the CelData only if the cel isn't linked
-  bool has_data = (cel->links() == 0);
-  write8(m_stream, has_data ? 1 : 0);
-  if (has_data) {
-    write_image(m_stream, cel->image());
-    write_celdata(m_stream, cel->data());
-  }
-  write_cel(m_stream, cel);
-  m_size = size_t(m_stream.tellp());
-
+  // We must suspend the cel after removing the cel, we cannot trigger
+  // onBeforeRemoveCel() with a cel without ID.
   removeCel(layer, cel);
+  m_suspendedCel.suspend(cel);
 }
 
 void AddCel::onRedo()
 {
   Layer* layer = this->layer();
+  Cel* cel = m_suspendedCel.restore();
   ASSERT(layer);
-
-  SubObjectsFromSprite io(layer->sprite());
-  bool has_data = (read8(m_stream) != 0);
-  if (has_data) {
-    ImageRef image(read_image(m_stream));
-    io.addImageRef(image);
-
-    CelDataRef celdata(read_celdata(m_stream, &io));
-    io.addCelDataRef(celdata);
-  }
-  Cel* cel = read_cel(m_stream, &io);
   ASSERT(cel);
 
   addCel(layer, cel);
-
-  m_stream.str(std::string());
-  m_stream.clear();
-  m_size = 0;
 }
 
 void AddCel::addCel(Layer* layer, Cel* cel)
@@ -111,8 +86,6 @@ void AddCel::removeCel(Layer* layer, Cel* cel)
   layer->incrementVersion();
 
   doc->notify_observers<DocEvent&>(&DocObserver::onAfterRemoveCel, ev);
-
-  delete cel;
 }
 
 }} // namespace app::cmd

src/app/cmd/add_cel.h

@@ -1,4 +1,5 @@
 // Aseprite
+// Copyright (C) 2025  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -11,11 +12,10 @@
 #include "app/cmd.h"
 #include "app/cmd/with_cel.h"
 #include "app/cmd/with_layer.h"
-
-#include <sstream>
+#include "app/cmd/with_suspended.h"
+#include "doc/cel.h"
 
 namespace doc {
-class Cel;
 class Layer;
 } // namespace doc
 
@@ -32,14 +32,13 @@ protected:
   void onExecute() override;
   void onUndo() override;
   void onRedo() override;
-  size_t onMemSize() const override { return sizeof(*this) + m_size; }
+  size_t onMemSize() const override { return sizeof(*this) + m_suspendedCel.size(); }
 
 private:
   void addCel(Layer* layer, Cel* cel);
   void removeCel(Layer* layer, Cel* cel);
 
-  size_t m_size;
-  std::stringstream m_stream;
+  WithSuspended<doc::Cel*> m_suspendedCel;
 };
 
 }} // namespace app::cmd

src/app/cmd/add_layer.cpp

@@ -13,8 +13,6 @@
 #include "app/doc.h"
 #include "app/doc_event.h"
 #include "doc/layer.h"
-#include "doc/layer_io.h"
-#include "doc/subobjects_io.h"
 
 namespace app { namespace cmd {
 
@@ -24,7 +22,6 @@ AddLayer::AddLayer(Layer* group, Layer* newLayer, Layer* afterThis)
   : m_group(group)
   , m_newLayer(newLayer)
   , m_afterThis(afterThis)
-  , m_size(0)
 {
 }
 
@@ -41,25 +38,19 @@ void AddLayer::onUndo()
 {
   Layer* group = m_group.layer();
   Layer* layer = m_newLayer.layer();
-
-  write_layer(m_stream, layer);
-  m_size = size_t(m_stream.tellp());
+  ASSERT(layer);
 
   removeLayer(group, layer);
+  m_suspendedLayer.suspend(layer);
 }
 
 void AddLayer::onRedo()
 {
   Layer* group = m_group.layer();
-  SubObjectsFromSprite io(group->sprite());
-  Layer* newLayer = read_layer(m_stream, &io);
+  Layer* newLayer = m_suspendedLayer.restore();
   Layer* afterThis = m_afterThis.layer();
 
   addLayer(group, newLayer, afterThis);
-
-  m_stream.str(std::string());
-  m_stream.clear();
-  m_size = 0;
 }
 
 void AddLayer::addLayer(Layer* group, Layer* newLayer, Layer* afterThis)
@@ -88,8 +79,6 @@ void AddLayer::removeLayer(Layer* group, Layer* layer)
   group->sprite()->incrementVersion();
 
   doc->notify_observers<DocEvent&>(&DocObserver::onAfterRemoveLayer, ev);
-
-  delete layer;
 }
 
 }} // namespace app::cmd

src/app/cmd/add_layer.h

@@ -1,4 +1,5 @@
 // Aseprite
+// Copyright (c) 2025  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -10,12 +11,8 @@
 
 #include "app/cmd.h"
 #include "app/cmd/with_layer.h"
-
-#include <sstream>
-
-namespace doc {
-class Layer;
-}
+#include "app/cmd/with_suspended.h"
+#include "doc/layer.h"
 
 namespace app { namespace cmd {
 using namespace doc;
@@ -28,7 +25,7 @@ protected:
   void onExecute() override;
   void onUndo() override;
   void onRedo() override;
-  size_t onMemSize() const override { return sizeof(*this) + m_size; }
+  size_t onMemSize() const override { return sizeof(*this) + m_suspendedLayer.size(); }
 
 private:
   void addLayer(Layer* group, Layer* newLayer, Layer* afterThis);
@@ -37,8 +34,7 @@ private:
   WithLayer m_group;
   WithLayer m_newLayer;
   WithLayer m_afterThis;
-  size_t m_size;
-  std::stringstream m_stream;
+  WithSuspended<doc::Layer*> m_suspendedLayer;
 };
 
 }} // namespace app::cmd

src/app/cmd/add_palette.cpp

@@ -11,30 +11,21 @@
 #include "app/cmd/add_palette.h"
 
 #include "doc/palette.h"
-#include "doc/palette_io.h"
 #include "doc/sprite.h"
 
 namespace app { namespace cmd {
 
 using namespace doc;
 
-AddPalette::AddPalette(Sprite* sprite, Palette* pal)
-  : WithSprite(sprite)
-  , m_size(0)
-  , m_frame(pal->frame())
+AddPalette::AddPalette(Sprite* sprite, Palette* pal) : WithSprite(sprite), m_palette(*pal)
 {
-  write_palette(m_stream, pal);
-  m_size = size_t(m_stream.tellp());
 }
 
 void AddPalette::onExecute()
 {
-  m_stream.seekp(0);
-
   Sprite* sprite = this->sprite();
-  Palette* pal = read_palette(m_stream);
 
-  sprite->setPalette(pal, true);
+  sprite->setPalette(&m_palette, true);
   sprite->incrementVersion();
 }
 
@@ -42,7 +33,7 @@ void AddPalette::onUndo()
 {
   Sprite* sprite = this->sprite();
 
-  sprite->deletePalette(m_frame);
+  sprite->deletePalette(m_palette.frame());
   sprite->incrementVersion();
 }
 

src/app/cmd/add_palette.h

@@ -1,4 +1,5 @@
 // Aseprite
+// Copyright (C) 2025  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -10,9 +11,7 @@
 
 #include "app/cmd.h"
 #include "app/cmd/with_sprite.h"
-#include "doc/frame.h"
-
-#include <sstream>
+#include "doc/palette.h"
 
 namespace doc {
 class Palette;
@@ -30,12 +29,10 @@ public:
 protected:
   void onExecute() override;
   void onUndo() override;
-  size_t onMemSize() const override { return sizeof(*this) + m_size; }
+  size_t onMemSize() const override { return sizeof(*this) + m_palette.getMemSize(); }
 
 private:
-  size_t m_size;
-  std::stringstream m_stream;
-  frame_t m_frame;
+  Palette m_palette;
 };
 
 }} // namespace app::cmd

src/app/cmd/add_slice.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 // Copyright (C) 2017  David Capello
 //
 // This program is distributed under the terms of
@@ -14,14 +14,13 @@
 #include "app/doc.h"
 #include "app/doc_event.h"
 #include "doc/slice.h"
-#include "doc/slice_io.h"
 #include "doc/sprite.h"
 
 namespace app { namespace cmd {
 
 using namespace doc;
 
-AddSlice::AddSlice(Sprite* sprite, Slice* slice) : WithSprite(sprite), WithSlice(slice), m_size(0)
+AddSlice::AddSlice(Sprite* sprite, Slice* slice) : WithSprite(sprite), WithSlice(slice)
 {
 }
 
@@ -37,22 +36,17 @@ void AddSlice::onUndo()
 {
   Sprite* sprite = this->sprite();
   Slice* slice = this->slice();
-  write_slice(m_stream, slice);
-  m_size = size_t(m_stream.tellp());
 
   removeSlice(sprite, slice);
+  m_suspendedSlice.suspend(slice);
 }
 
 void AddSlice::onRedo()
 {
   Sprite* sprite = this->sprite();
-  Slice* slice = read_slice(m_stream);
+  Slice* slice = m_suspendedSlice.restore();
 
   addSlice(sprite, slice);
-
-  m_stream.str(std::string());
-  m_stream.clear();
-  m_size = 0;
 }
 
 void AddSlice::addSlice(Sprite* sprite, Slice* slice)
@@ -77,7 +71,6 @@ void AddSlice::removeSlice(Sprite* sprite, Slice* slice)
 
   sprite->slices().remove(slice);
   sprite->incrementVersion();
-  delete slice;
 }
 
 }} // namespace app::cmd

src/app/cmd/add_slice.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 // Copyright (C) 2017  David Capello
 //
 // This program is distributed under the terms of
@@ -12,8 +12,8 @@
 #include "app/cmd.h"
 #include "app/cmd/with_slice.h"
 #include "app/cmd/with_sprite.h"
-
-#include <sstream>
+#include "app/cmd/with_suspended.h"
+#include "doc/slice.h"
 
 namespace app { namespace cmd {
 using namespace doc;
@@ -28,14 +28,13 @@ protected:
   void onExecute() override;
   void onUndo() override;
   void onRedo() override;
-  size_t onMemSize() const override { return sizeof(*this) + m_size; }
+  size_t onMemSize() const override { return sizeof(*this) + m_suspendedSlice.size(); }
 
 private:
   void addSlice(Sprite* sprite, Slice* slice);
   void removeSlice(Sprite* sprite, Slice* slice);
 
-  size_t m_size;
-  std::stringstream m_stream;
+  WithSuspended<doc::Slice*> m_suspendedSlice;
 };
 
 }} // namespace app::cmd

src/app/cmd/add_tag.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -15,13 +15,12 @@
 #include "app/doc_event.h"
 #include "doc/sprite.h"
 #include "doc/tag.h"
-#include "doc/tag_io.h"
 
 namespace app { namespace cmd {
 
 using namespace doc;
 
-AddTag::AddTag(Sprite* sprite, Tag* tag) : WithSprite(sprite), WithTag(tag), m_size(0)
+AddTag::AddTag(Sprite* sprite, Tag* tag) : WithSprite(sprite), WithTag(tag)
 {
 }
 
@@ -45,8 +44,6 @@ void AddTag::onUndo()
 {
   Sprite* sprite = this->sprite();
   Tag* tag = this->tag();
-  write_tag(m_stream, tag);
-  m_size = size_t(m_stream.tellp());
 
   // Notify observers about the new frame.
   {
@@ -59,21 +56,18 @@ void AddTag::onUndo()
 
   sprite->tags().remove(tag);
   sprite->incrementVersion();
-  delete tag;
+
+  m_suspendedTag.suspend(tag);
 }
 
 void AddTag::onRedo()
 {
   Sprite* sprite = this->sprite();
-  Tag* tag = read_tag(m_stream);
+  Tag* tag = m_suspendedTag.restore();
 
   sprite->tags().add(tag);
   sprite->incrementVersion();
 
-  m_stream.str(std::string());
-  m_stream.clear();
-  m_size = 0;
-
   // Notify observers about the new frame.
   Doc* doc = static_cast<Doc*>(sprite->document());
   DocEvent ev(doc);

src/app/cmd/add_tag.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -11,9 +11,9 @@
 
 #include "app/cmd.h"
 #include "app/cmd/with_sprite.h"
+#include "app/cmd/with_suspended.h"
 #include "app/cmd/with_tag.h"
-
-#include <sstream>
+#include "doc/tag.h"
 
 namespace app { namespace cmd {
 using namespace doc;
@@ -28,11 +28,10 @@ protected:
   void onExecute() override;
   void onUndo() override;
   void onRedo() override;
-  size_t onMemSize() const override { return sizeof(*this) + m_size; }
+  size_t onMemSize() const override { return sizeof(*this) + m_suspendedTag.size(); }
 
 private:
-  size_t m_size;
-  std::stringstream m_stream;
+  WithSuspended<doc::Tag*> m_suspendedTag;
 };
 
 }} // namespace app::cmd

src/app/cmd/add_tile.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2022  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -11,7 +11,6 @@
 #include "app/cmd/add_tile.h"
 
 #include "app/doc.h"
-#include "doc/image_io.h"
 #include "doc/sprite.h"
 #include "doc/tileset.h"
 #include "doc/tilesets.h"
@@ -20,8 +19,6 @@ namespace app { namespace cmd {
 
 AddTile::AddTile(doc::Tileset* tileset, const doc::ImageRef& image, const doc::UserData& userData)
   : WithTileset(tileset)
-  , WithImage(image.get())
-  , m_size(0)
   , m_tileIndex(doc::notile)
   , m_imageRef(image)
   , m_userData(userData)
@@ -30,10 +27,8 @@ AddTile::AddTile(doc::Tileset* tileset, const doc::ImageRef& image, const doc::U
 
 AddTile::AddTile(doc::Tileset* tileset, const doc::tile_index ti)
   : WithTileset(tileset)
-  , WithImage(tileset->get(ti).get())
-  , m_size(0)
   , m_tileIndex(ti)
-  , m_imageRef(nullptr)
+  , m_imageRef(tileset->get(ti))
   , m_userData(tileset->getTileData(ti))
 {
 }
@@ -44,14 +39,11 @@ void AddTile::onExecute()
   ASSERT(tileset);
 
   if (m_tileIndex != doc::notile) {
-    ASSERT(!m_imageRef);
     tileset->sprite()->incrementVersion();
     tileset->incrementVersion();
   }
   else {
-    ASSERT(m_imageRef);
     addTile(tileset, m_imageRef, m_userData);
-    m_imageRef.reset();
   }
 }
 
@@ -60,8 +52,9 @@ void AddTile::onUndo()
   doc::Tileset* tileset = this->tileset();
   ASSERT(tileset);
 
-  write_image(m_stream, image());
-  m_size = size_t(m_stream.tellp());
+  ASSERT(m_imageRef);
+  m_suspendedImage.suspend(m_imageRef);
+  m_imageRef.reset();
 
   tileset->erase(m_tileIndex);
 
@@ -74,15 +67,10 @@ void AddTile::onRedo()
   doc::Tileset* tileset = this->tileset();
 
   ASSERT(!m_imageRef);
-  m_imageRef.reset(read_image(m_stream));
+  m_imageRef = m_suspendedImage.restore();
   ASSERT(m_imageRef);
 
   addTile(tileset, m_imageRef, m_userData);
-  m_imageRef.reset();
-
-  m_stream.str(std::string());
-  m_stream.clear();
-  m_size = 0;
 }
 
 void AddTile::onFireNotifications()

src/app/cmd/add_tile.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2022  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -9,14 +9,12 @@
 #pragma once
 
 #include "app/cmd.h"
-#include "app/cmd/with_image.h"
+#include "app/cmd/with_suspended.h"
 #include "app/cmd/with_tileset.h"
 #include "doc/image_ref.h"
 #include "doc/tile.h"
 #include "doc/user_data.h"
 
-#include <sstream>
-
 namespace doc {
 class Tileset;
 }
@@ -24,12 +22,9 @@ class Tileset;
 namespace app { namespace cmd {
 
 class AddTile : public Cmd,
-                public WithTileset,
-                public WithImage {
+                public WithTileset {
 public:
-  AddTile(doc::Tileset* tileset,
-          const doc::ImageRef& image,
-          const doc::UserData& userData = UserData());
+  AddTile(doc::Tileset* tileset, const doc::ImageRef& image, const doc::UserData& userData = {});
   AddTile(doc::Tileset* tileset, const doc::tile_index ti);
 
   doc::tile_index tileIndex() const { return m_tileIndex; }
@@ -42,14 +37,13 @@ protected:
   size_t onMemSize() const override
   {
     // TODO add m_userData size
-    return sizeof(*this) + m_size;
+    return sizeof(*this) + m_suspendedImage.size();
   }
 
 private:
   void addTile(doc::Tileset* tileset, const doc::ImageRef& image, const doc::UserData& userData);
 
-  size_t m_size;
-  std::stringstream m_stream;
+  WithSuspended<doc::ImageRef> m_suspendedImage;
   doc::tile_index m_tileIndex;
   doc::ImageRef m_imageRef;
   doc::UserData m_userData;

src/app/cmd/add_tileset.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -11,9 +11,7 @@
 #include "app/cmd/add_tileset.h"
 
 #include "doc/sprite.h"
-#include "doc/subobjects_io.h"
 #include "doc/tileset.h"
-#include "doc/tileset_io.h"
 #include "doc/tilesets.h"
 
 namespace app { namespace cmd {
@@ -23,7 +21,6 @@ using namespace doc;
 AddTileset::AddTileset(doc::Sprite* sprite, doc::Tileset* tileset)
   : WithSprite(sprite)
   , WithTileset(tileset)
-  , m_size(0)
   , m_tilesetIndex(-1)
 {
 }
@@ -31,7 +28,6 @@ AddTileset::AddTileset(doc::Sprite* sprite, doc::Tileset* tileset)
 AddTileset::AddTileset(doc::Sprite* sprite, const doc::tileset_index tsi)
   : WithSprite(sprite)
   , WithTileset(sprite->tilesets()->get(tsi))
-  , m_size(0)
   , m_tilesetIndex(tsi)
 {
 }
@@ -46,28 +42,20 @@ void AddTileset::onExecute()
 void AddTileset::onUndo()
 {
   doc::Tileset* tileset = this->tileset();
-  write_tileset(m_stream, tileset);
-  m_size = size_t(m_stream.tellp());
+  m_suspendedTileset.suspend(tileset);
 
   doc::Sprite* sprite = this->sprite();
   sprite->tilesets()->erase(m_tilesetIndex);
 
   sprite->incrementVersion();
   sprite->tilesets()->incrementVersion();
-
-  delete tileset;
 }
 
 void AddTileset::onRedo()
 {
-  auto sprite = this->sprite();
-  doc::Tileset* tileset = read_tileset(m_stream, sprite);
+  doc::Tileset* tileset = m_suspendedTileset.restore();
 
   addTileset(tileset);
-
-  m_stream.str(std::string());
-  m_stream.clear();
-  m_size = 0;
 }
 
 void AddTileset::addTileset(doc::Tileset* tileset)

src/app/cmd/add_tileset.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -10,10 +10,10 @@
 
 #include "app/cmd.h"
 #include "app/cmd/with_sprite.h"
+#include "app/cmd/with_suspended.h"
 #include "app/cmd/with_tileset.h"
 #include "doc/tile.h"
-
-#include <sstream>
+#include "doc/tileset.h"
 
 namespace doc {
 class Tileset;
@@ -34,13 +34,12 @@ protected:
   void onExecute() override;
   void onUndo() override;
   void onRedo() override;
-  size_t onMemSize() const override { return sizeof(*this) + m_size; }
+  size_t onMemSize() const override { return sizeof(*this) + m_suspendedTileset.size(); }
 
 private:
   void addTileset(doc::Tileset* tileset);
 
-  size_t m_size;
-  std::stringstream m_stream;
+  WithSuspended<doc::Tileset*> m_suspendedTileset;
   doc::tileset_index m_tilesetIndex;
 };
 

src/app/cmd/replace_image.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2023  Igara Studio S.A.
+// Copyright (C) 2023-2025  Igara Studio S.A.
 // Copyright (C) 2001-2015  David Capello
 //
 // This program is distributed under the terms of
@@ -14,10 +14,8 @@
 #include "doc/cel.h"
 #include "doc/cels_range.h"
 #include "doc/image.h"
-#include "doc/image_io.h"
 #include "doc/image_ref.h"
 #include "doc/sprite.h"
-#include "doc/subobjects_io.h"
 #include "doc/tilesets.h"
 
 namespace app { namespace cmd {

src/app/cmd/replace_image.h

@@ -12,8 +12,6 @@
 #include "app/cmd/with_sprite.h"
 #include "doc/image_ref.h"
 
-#include <sstream>
-
 namespace app { namespace cmd {
 using namespace doc;
 

src/app/cmd/replace_tileset.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2021  Igara Studio S.A.
+// Copyright (C) 2021-2025  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -14,7 +14,6 @@
 #include "doc/layer_tilemap.h"
 #include "doc/sprite.h"
 #include "doc/tileset.h"
-#include "doc/tileset_io.h"
 #include "doc/tilesets.h"
 
 namespace app { namespace cmd {
@@ -40,16 +39,11 @@ void ReplaceTileset::onExecute()
     m_newTileset = nullptr;
   }
   else {
-    restoreTileset = doc::read_tileset(m_stream, spr, true);
+    restoreTileset = m_suspendedTileset.restore();
   }
 
-  m_stream.str(std::string());
-  m_stream.clear();
-  doc::write_tileset(m_stream, actualTileset);
-  m_size = size_t(m_stream.tellp());
-
   replaceTileset(restoreTileset);
-  delete actualTileset;
+  m_suspendedTileset.suspend(actualTileset);
 }
 
 void ReplaceTileset::replaceTileset(Tileset* newTileset)

src/app/cmd/replace_tileset.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2021  Igara Studio S.A.
+// Copyright (C) 2021-2025  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -10,10 +10,9 @@
 
 #include "app/cmd.h"
 #include "app/cmd/with_sprite.h"
+#include "app/cmd/with_suspended.h"
 #include "doc/tileset.h"
 
-#include <sstream>
-
 namespace app { namespace cmd {
 
 class ReplaceTileset : public Cmd,
@@ -25,15 +24,14 @@ protected:
   void onExecute() override;
   void onUndo() override { onExecute(); }
   void onRedo() override { onExecute(); }
-  size_t onMemSize() const override { return sizeof(*this) + m_size; }
+  size_t onMemSize() const override { return sizeof(*this) + m_suspendedTileset.size(); }
 
 private:
   void replaceTileset(doc::Tileset* newTileset);
 
   doc::tileset_index m_tsi;
   doc::Tileset* m_newTileset;
-  std::stringstream m_stream;
-  size_t m_size = 0;
+  WithSuspended<doc::Tileset*> m_suspendedTileset;
 };
 
 }} // namespace app::cmd

src/app/cmd/set_cel_data.cpp

@@ -12,11 +12,9 @@
 
 #include "doc/cel.h"
 #include "doc/image.h"
-#include "doc/image_io.h"
 #include "doc/image_ref.h"
 #include "doc/layer.h"
 #include "doc/sprite.h"
-#include "doc/subobjects_io.h"
 
 namespace app { namespace cmd {
 

src/app/cmd/set_cel_data.h

@@ -12,8 +12,6 @@
 #include "app/cmd/with_cel.h"
 #include "doc/cel_data.h"
 
-#include <sstream>
-
 namespace app { namespace cmd {
 using namespace doc;
 

src/app/cmd/set_mask.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -13,7 +13,6 @@
 #include "app/cmd/with_document.h"
 
 #include <memory>
-#include <sstream>
 
 namespace doc {
 class Mask;

src/app/cmd/with_suspended.h

@@ -0,0 +1,62 @@
+// Aseprite
+// Copyright (C) 2025  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifndef APP_CMD_WITH_SUSPEND_H_INCLUDED
+#define APP_CMD_WITH_SUSPEND_H_INCLUDED
+#pragma once
+
+#include "doc/object.h"
+
+#include <type_traits>
+
+namespace app { namespace cmd {
+
+// Auxiliary class to keep a doc::Object in memory but without IDs,
+// and to restore all its IDs when it's required.
+template<typename T>
+class WithSuspended {
+public:
+  ~WithSuspended()
+  {
+    // If the object is suspended it's not included in the Sprite
+    // hierarchy, so it will not be automatically deleted, thereby we
+    // have to delete the object to avoid a memory leak.
+    if constexpr (std::is_pointer_v<T>)
+      delete m_object;
+  }
+
+  T object() { return m_object; }
+  size_t size() const { return m_size; }
+
+  void suspend(T object)
+  {
+    ASSERT(!m_object);
+
+    m_object = object;
+    m_size = m_object->getMemSize();
+    m_object->suspendObject();
+  }
+
+  T restore()
+  {
+    ASSERT(m_object);
+    T object = m_object;
+
+    m_object->restoreObject();
+    m_object = nullptr;
+    m_size = 0;
+
+    return object;
+  }
+
+private:
+  size_t m_size = 0;
+  T m_object = nullptr;
+};
+
+}} // namespace app::cmd
+
+#endif

src/app/commands/filters/filter_manager_impl.cpp

@@ -325,10 +325,15 @@ void FilterManagerImpl::applyToTarget()
 void FilterManagerImpl::initTransaction()
 {
   ASSERT(!m_tx);
-  m_writer.reset(new ContextWriter(m_reader));
+  m_writer = std::make_unique<ContextWriter>(m_reader);
   m_tx.reset(new Tx(*m_writer, m_filter->getName(), ModifyDocument));
 }
 
+void FilterManagerImpl::updateWriterThread()
+{
+  document()->updateWriterThread();
+}
+
 bool FilterManagerImpl::isTransaction() const
 {
   return (m_tx != nullptr);

src/app/commands/filters/filter_manager_impl.h

@@ -93,6 +93,7 @@ public:
   void applyToTarget();
 
   void initTransaction();
+  void updateWriterThread();
   bool isTransaction() const;
   void commitTransaction();
 

src/app/commands/filters/filter_worker.cpp

@@ -118,7 +118,13 @@ FilterWorker::~FilterWorker()
 
 void FilterWorker::run()
 {
-  // Initialize writting transaction
+  // Initialize writing transaction from the main thread. This is
+  // required to get the activeSite() from the UIContext from
+  // CmdTransaction::calcSpritePosition().
+  //
+  // The document will keep the UI thread associated as the "writer"
+  // thread, but that will be updated later in
+  // applyFilterInBackground() with the worker thread ID.
   m_filterMgr->initTransaction();
 
   std::thread thread;
@@ -182,6 +188,11 @@ bool FilterWorker::isCancelled()
 void FilterWorker::applyFilterInBackground()
 {
   try {
+    // This background thread is the new writer. This is required to
+    // avoid read-locking from the UI thread from Editor and Timeline
+    // onPaint() events.
+    m_filterMgr->updateWriterThread();
+
     // Apply the filter
     m_filterMgr->applyToTarget();
 

src/app/doc.cpp

@@ -124,6 +124,11 @@ Doc::LockResult Doc::upgradeToWrite(int timeout)
   return res;
 }
 
+void Doc::updateWriterThread()
+{
+  m_rwLock.updateWriterThread();
+}
+
 void Doc::downgradeToRead(LockResult lockResult)
 {
   DOC_TRACE("DOC: downgradeToRead", this, (int)lockResult);

src/app/doc.h

@@ -82,6 +82,7 @@ public:
   LockResult readLock(int timeout);
   LockResult writeLock(int timeout);
   LockResult upgradeToWrite(int timeout);
+  void updateWriterThread();
   void downgradeToRead(LockResult lockResult);
   void unlock(LockResult lockResult);
 

src/app/ui/editor/editor.cpp

@@ -2810,7 +2810,7 @@ void Editor::pasteImage(const Image* image, const Mask* mask, const gfx::Point*
   ASSERT(image);
 
   std::unique_ptr<Mask> temp_mask;
-  if (!mask) {
+  if (!mask || mask->bounds().isEmpty()) {
     gfx::Rect visibleBounds = getVisibleSpriteBounds();
     gfx::Rect imageBounds = image->bounds();
 

src/app/ui_context.cpp

@@ -25,6 +25,7 @@
 #include "app/ui/workspace.h"
 #include "app/ui/workspace_tabs.h"
 #include "doc/sprite.h"
+#include "ui/manager.h"
 #include "ui/system.h"
 
 #include <algorithm>
@@ -120,6 +121,10 @@ void UIContext::setActiveView(DocView* docView)
   mainWin->getTimeline()->updateUsingEditor(editor);
   mainWin->getPreviewEditor()->updateUsingEditor(editor);
 
+  // Update mouse widgets immediately after changing views rather
+  // than waiting for mouse movement.
+  mainWin->manager()->_updateMouseWidgets();
+
   // Change the image-type of color bar.
   ColorBar::instance()->setPixelFormat(app_get_current_pixel_format());
 

src/doc/cel.cpp

@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2019-2024 Igara Studio S.A.
+// Copyright (c) 2019-2025 Igara Studio S.A.
 // Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -27,6 +27,7 @@ Cel::Cel(frame_t frame, const ImageRef& image)
   , m_frame(frame)
   , m_data(new CelData(image))
 {
+  ++m_data->m_refs;
 }
 
 Cel::Cel(frame_t frame, const CelDataRef& celData)
@@ -35,6 +36,13 @@ Cel::Cel(frame_t frame, const CelDataRef& celData)
   , m_frame(frame)
   , m_data(celData)
 {
+  ++m_data->m_refs;
+}
+
+Cel::~Cel()
+{
+  if (m_data)
+    --m_data->m_refs;
 }
 
 // static
@@ -65,7 +73,11 @@ void Cel::setFrame(frame_t frame)
 void Cel::setDataRef(const CelDataRef& celData)
 {
   ASSERT(celData);
+  if (m_data)
+    --m_data->m_refs;
   m_data = celData;
+  if (m_data)
+    ++m_data->m_refs;
 }
 
 void Cel::setPosition(int x, int y)
@@ -119,10 +131,10 @@ Sprite* Cel::sprite() const
 Cel* Cel::link() const
 {
   ASSERT(m_data);
-  if (m_data.get() == NULL)
-    return NULL;
+  if (!m_data)
+    return nullptr;
 
-  if (!m_data.unique()) {
+  if (links() > 0) {
     for (frame_t fr = 0; fr < m_frame; ++fr) {
       Cel* possible = m_layer->cel(fr);
       if (possible && possible->dataRef().get() == m_data.get())
@@ -135,16 +147,32 @@ Cel* Cel::link() const
 
 std::size_t Cel::links() const
 {
-  std::size_t links = 0;
+  if (m_data)
+    return std::max<std::size_t>(0, m_data->refs() - 1);
+  return 0;
+}
 
-  Sprite* sprite = this->sprite();
-  for (frame_t fr = 0; fr < sprite->totalFrames(); ++fr) {
-    Cel* cel = m_layer->cel(fr);
-    if (cel && cel != this && cel->dataRef().get() == m_data.get())
-      ++links;
+void Cel::suspendObject()
+{
+  if (m_data) {
+    if (--m_data->m_refs == 0) {
+      // Suspend the CelData only if this was the latest cel referencing it.
+      m_data->suspendObject();
+    }
   }
 
-  return links;
+  Object::suspendObject();
+}
+
+void Cel::restoreObject()
+{
+  Object::restoreObject();
+
+  if (m_data) {
+    if (++m_data->m_refs == 1) {
+      m_data->restoreObject();
+    }
+  }
 }
 
 void Cel::setParentLayer(LayerImage* layer)

src/doc/cel.h

@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2019-2024 Igara Studio S.A.
+// Copyright (c) 2019-2025 Igara Studio S.A.
 // Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -28,6 +28,7 @@ class Cel : public Object {
 public:
   Cel(frame_t frame, const ImageRef& image);
   Cel(frame_t frame, const CelDataRef& celData);
+  ~Cel();
 
   static Cel* MakeCopy(const frame_t newFrame, const Cel* other);
   static Cel* MakeLink(const frame_t newFrame, const Cel* other);
@@ -65,7 +66,9 @@ public:
   void setOpacity(int opacity);
   void setZIndex(int zindex);
 
-  virtual int getMemSize() const override { return sizeof(Cel) + m_data->getMemSize(); }
+  int getMemSize() const override { return sizeof(Cel) + m_data->getMemSize(); }
+  void suspendObject() override;
+  void restoreObject() override;
 
   void setParentLayer(LayerImage* layer);
   Grid grid() const;

src/doc/cel_data.cpp

@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2019-2022 Igara Studio S.A.
+// Copyright (c) 2019-2025 Igara Studio S.A.
 // Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -23,7 +23,6 @@ namespace doc {
 CelData::CelData(const ImageRef& image)
   : WithUserData(ObjectType::CelData)
   , m_image(image)
-  , m_opacity(255)
   , m_bounds(0, 0, image ? image->width() : 0, image ? image->height() : 0)
   , m_boundsF(nullptr)
 {
@@ -57,6 +56,20 @@ void CelData::setPosition(const gfx::Point& pos)
     m_boundsF->setOrigin(gfx::PointF(pos));
 }
 
+void CelData::suspendObject()
+{
+  if (m_image)
+    m_image->suspendObject();
+  WithUserData::suspendObject();
+}
+
+void CelData::restoreObject()
+{
+  WithUserData::restoreObject();
+  if (m_image)
+    m_image->restoreObject();
+}
+
 void CelData::adjustBounds(Layer* layer)
 {
   ASSERT(m_image);

src/doc/cel_data.h

@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (C) 2019-2022  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -18,10 +18,13 @@
 
 namespace doc {
 
+class Cel;
 class Layer;
 class Tileset;
 
 class CelData : public WithUserData {
+  friend class Cel;
+
 public:
   CelData(const ImageRef& image);
   CelData(const CelData& celData);
@@ -30,7 +33,8 @@ public:
   gfx::Point position() const { return m_bounds.origin(); }
   const gfx::Rect& bounds() const { return m_bounds; }
   int opacity() const { return m_opacity; }
-  Image* image() const { return const_cast<Image*>(m_image.get()); };
+  std::size_t refs() const { return m_refs; }
+  Image* image() const { return const_cast<Image*>(m_image.get()); }
   ImageRef imageRef() const { return m_image; }
 
   // Returns a rectangle with the bounds of the image (width/height
@@ -79,17 +83,20 @@ public:
 
   bool hasBoundsF() const { return m_boundsF != nullptr; }
 
-  virtual int getMemSize() const override
+  int getMemSize() const override
   {
     ASSERT(m_image);
     return sizeof(CelData) + m_image->getMemSize();
   }
+  void suspendObject() override;
+  void restoreObject() override;
 
   void adjustBounds(Layer* layer);
 
 private:
   ImageRef m_image;
-  int m_opacity;
+  int m_opacity = 255;
+  std::size_t m_refs = 0;
   gfx::Rect m_bounds;
 
   // Special bounds for reference layers that can have subpixel

src/doc/layer.cpp

@@ -249,6 +249,28 @@ int LayerImage::getMemSize() const
   return size;
 }
 
+void LayerImage::suspendObject()
+{
+  CelIterator it = getCelBegin();
+  CelIterator end = getCelEnd();
+  for (; it != end; ++it) {
+    Cel* cel = *it;
+    cel->suspendObject();
+  }
+  Layer::suspendObject();
+}
+
+void LayerImage::restoreObject()
+{
+  Layer::restoreObject();
+  CelIterator it = getCelBegin();
+  CelIterator end = getCelEnd();
+  for (; it != end; ++it) {
+    Cel* cel = *it;
+    cel->restoreObject();
+  }
+}
+
 void LayerImage::destroyAllCels()
 {
   CelIterator it = getCelBegin();
@@ -430,6 +452,20 @@ int LayerGroup::getMemSize() const
   return size;
 }
 
+void LayerGroup::suspendObject()
+{
+  for (Layer* child : m_layers)
+    child->suspendObject();
+  Layer::suspendObject();
+}
+
+void LayerGroup::restoreObject()
+{
+  Layer::restoreObject();
+  for (Layer* child : m_layers)
+    child->restoreObject();
+}
+
 Layer* LayerGroup::firstLayerInWholeHierarchy() const
 {
   Layer* layer = firstLayer();

src/doc/layer.h

@@ -60,7 +60,7 @@ protected:
 public:
   virtual ~Layer();
 
-  virtual int getMemSize() const override;
+  int getMemSize() const override;
 
   const std::string& name() const { return m_name; }
   void setName(const std::string& name) { m_name = name; }
@@ -170,7 +170,9 @@ public:
   explicit LayerImage(Sprite* sprite);
   virtual ~LayerImage();
 
-  virtual int getMemSize() const override;
+  int getMemSize() const override;
+  void suspendObject() override;
+  void restoreObject() override;
 
   void addCel(Cel* cel);
   void removeCel(Cel* cel);
@@ -207,7 +209,9 @@ public:
   explicit LayerGroup(Sprite* sprite);
   virtual ~LayerGroup();
 
-  virtual int getMemSize() const override;
+  int getMemSize() const override;
+  void suspendObject() override;
+  void restoreObject() override;
 
   const LayerList& layers() const { return m_layers; }
   int layersCount() const { return (int)m_layers.size(); }

src/doc/object.cpp

@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (C) 2019-2022  Igara Studio S.A.
+// Copyright (C) 2019-2025  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -23,13 +23,14 @@ static ObjectId newId = 0;
 // TODO Profile this and see if an unordered_map is better
 static std::map<ObjectId, Object*> objects;
 
-Object::Object(ObjectType type) : m_type(type), m_id(0), m_version(0)
+Object::Object(ObjectType type) : m_type(type)
 {
 }
 
 Object::Object(const Object& other)
   : m_type(other.m_type)
-  , m_id(0)      // We don't copy the ID
+  , m_id(NullId) // We don't copy the ID
+  , m_suspendedId(NullId)
   , m_version(0) // We don't copy the version
 {
 }
@@ -37,7 +38,7 @@ Object::Object(const Object& other)
 Object::~Object()
 {
   if (m_id)
-    setId(0);
+    setId(NullId);
 }
 
 int Object::getMemSize() const
@@ -47,6 +48,9 @@ int Object::getMemSize() const
 
 const ObjectId Object::id() const
 {
+  // We cannot ask for the ID from a "suspended" object.
+  ASSERT(m_suspendedId == NullId);
+
   // The first time the ID is request, we store the object in the
   // "objects" hash table.
   if (!m_id) {
@@ -99,6 +103,20 @@ void Object::setVersion(ObjectVersion version)
   m_version = version;
 }
 
+void Object::suspendObject()
+{
+  ASSERT(m_suspendedId == NullId);
+  m_suspendedId = m_id;
+  setId(NullId);
+}
+
+void Object::restoreObject()
+{
+  ASSERT(m_id == NullId);
+  setId(m_suspendedId);
+  m_suspendedId = NullId;
+}
+
 Object* get_object(ObjectId id)
 {
   const std::lock_guard lock(g_mutex);

src/doc/object.h

@@ -1,4 +1,5 @@
 // Aseprite Document Library
+// Copyright (c) 2025  Igara Studio S.A.
 // Copyright (c) 2001-2015 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -9,6 +10,7 @@
 #pragma once
 
 #include "doc/object_id.h"
+#include "doc/object_ids.h"
 #include "doc/object_type.h"
 #include "doc/object_version.h"
 
@@ -33,14 +35,24 @@ public:
   // object use.
   virtual int getMemSize() const;
 
+  // Removes or restore the ID of this object (and all its children)
+  // to keep this object in a "suspended" state (e.g. in the undo
+  // history) or to recover the object from a suspended state.
+  virtual void suspendObject();
+  virtual void restoreObject();
+
 private:
   ObjectType m_type;
 
   // Unique identifier for this object (it is assigned by
   // Objects class).
-  mutable ObjectId m_id;
+  mutable ObjectId m_id = NullId;
 
-  ObjectVersion m_version;
+  // ID saved when the objects is "deleted" but stored in the undo
+  // history. It's a way to save the previous ID and restore it.
+  ObjectId m_suspendedId = NullId;
+
+  ObjectVersion m_version = 0;
 
   // Disable copy assignment
   Object& operator=(const Object&);

src/doc/object_id.h

@@ -1,4 +1,5 @@
 // Aseprite Document Library
+// Copyright (c) 2025 Igara Studio S.A.
 // Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -12,9 +13,9 @@
 
 namespace doc {
 
-typedef uint32_t ObjectId;
+using ObjectId = uint32_t;
 
-const ObjectId NullId = 0;
+constexpr const ObjectId NullId = 0;
 
 } // namespace doc