PixelPaint: Use UndoStack instead of History

This allows to share more code with other undo systems.

Applications/PixelPaint/CMakeLists.txt

@@ -5,7 +5,6 @@ set(SOURCES
     CreateNewLayerDialog.cpp
     EllipseTool.cpp
     EraseTool.cpp
-    History.cpp
     Image.cpp
     ImageEditor.cpp
     Layer.cpp

Applications/PixelPaint/History.cpp

@@ -1,73 +0,0 @@
-/*
- * Copyright (c) 2020, Ben Jilks <benjyjilks@gmail.com>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "History.h"
-#include "Image.h"
-#include "Layer.h"
-#include <AK/LogStream.h>
-#include <utility>
-
-namespace PixelPaint {
-
-void History::on_action(const Image& image)
-{
-    m_snapshots.shrink(m_snapshots.size() - m_current_index_back_into_history);
-    m_current_index_back_into_history = 0;
-    m_snapshots.append(image.take_snapshot());
-    if (m_snapshots.size() > s_max_size)
-        m_snapshots.take_first();
-}
-
-bool History::undo(Image& image)
-{
-    if (m_snapshots.size() - m_current_index_back_into_history - 1 <= 0)
-        return false;
-
-    m_current_index_back_into_history += 1;
-    const Image& last_snapshot = *m_snapshots[m_snapshots.size() - m_current_index_back_into_history - 1];
-    image.restore_snapshot(last_snapshot);
-    return true;
-}
-
-bool History::redo(Image& image)
-{
-    if (m_current_index_back_into_history <= 0)
-        return false;
-
-    const Image& last_snapshot = *m_snapshots[m_snapshots.size() - m_current_index_back_into_history];
-    m_current_index_back_into_history -= 1;
-    image.restore_snapshot(last_snapshot);
-    return true;
-}
-
-void History::reset(const Image& image)
-{
-    m_snapshots.clear();
-    m_current_index_back_into_history = 0;
-    on_action(image);
-}
-
-}

Applications/PixelPaint/History.h

@@ -1,54 +0,0 @@
-/*
- * Copyright (c) 2020, Ben Jilks <benjyjilks@gmail.com>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#pragma once
-
-#include <AK/String.h>
-#include <AK/Vector.h>
-
-namespace PixelPaint {
-
-class Image;
-
-class History {
-    AK_MAKE_NONCOPYABLE(History);
-    AK_MAKE_NONMOVABLE(History);
-
-public:
-    History() = default;
-
-    void on_action(const Image&);
-    bool undo(Image&);
-    bool redo(Image&);
-    void reset(const Image&);
-
-private:
-    static constexpr int s_max_size = 50;
-    Vector<RefPtr<Image>> m_snapshots;
-    int m_current_index_back_into_history { 0 };
-};
-
-}

Applications/PixelPaint/Image.cpp

@@ -312,4 +312,20 @@ void Image::did_change()
         client->image_did_change();
 }
 
+ImageUndoCommand::ImageUndoCommand(Image& image)
+    : m_snapshot(image.take_snapshot())
+    , m_image(image)
+{
+}
+
+void ImageUndoCommand::undo()
+{
+    m_image.restore_snapshot(*m_snapshot);
+}
+
+void ImageUndoCommand::redo()
+{
+    undo();
+}
+
 }

Applications/PixelPaint/Image.h

@@ -31,6 +31,7 @@
 #include <AK/RefCounted.h>
 #include <AK/RefPtr.h>
 #include <AK/Vector.h>
+#include <LibGUI/Command.h>
 #include <LibGUI/Forward.h>
 #include <LibGfx/Forward.h>
 #include <LibGfx/Rect.h>
@@ -98,4 +99,16 @@ private:
     HashTable<ImageClient*> m_clients;
 };
 
+class ImageUndoCommand : public GUI::Command {
+public:
+    ImageUndoCommand(Image& image);
+
+    virtual void undo() override;
+    virtual void redo() override;
+
+private:
+    RefPtr<Image> m_snapshot;
+    Image& m_image;
+};
+
 }

Applications/PixelPaint/ImageEditor.cpp

@@ -28,6 +28,7 @@
 #include "Image.h"
 #include "Layer.h"
 #include "Tool.h"
+#include <LibGUI/Command.h>
 #include <LibGUI/Painter.h>
 #include <LibGfx/Palette.h>
 #include <LibGfx/Rect.h>
@@ -35,6 +36,7 @@
 namespace PixelPaint {
 
 ImageEditor::ImageEditor()
+    : m_undo_stack(make<GUI::UndoStack>())
 {
     set_focus_policy(GUI::FocusPolicy::StrongFocus);
 }
@@ -52,7 +54,8 @@ void ImageEditor::set_image(RefPtr<Image> image)
 
     m_image = move(image);
     m_active_layer = nullptr;
-    m_history.reset(*m_image);
+    m_undo_stack = make<GUI::UndoStack>();
+    m_undo_stack->push(make<ImageUndoCommand>(*m_image));
     update();
     relayout();
 
@@ -64,14 +67,16 @@ void ImageEditor::did_complete_action()
 {
     if (!m_image)
         return;
-    m_history.on_action(*m_image);
+    m_undo_stack->finalize_current_combo();
+    m_undo_stack->push(make<ImageUndoCommand>(*m_image));
 }
 
 bool ImageEditor::undo()
 {
     if (!m_image)
         return false;
-    if (m_history.undo(*m_image)) {
+    if (m_undo_stack->can_undo()) {
+        m_undo_stack->undo();
         layers_did_change();
         return true;
     }
@@ -82,7 +87,8 @@ bool ImageEditor::redo()
 {
     if (!m_image)
         return false;
-    if (m_history.redo(*m_image)) {
+    if (m_undo_stack->can_redo()) {
+        m_undo_stack->redo();
         layers_did_change();
         return true;
     }

Applications/PixelPaint/ImageEditor.h

@@ -26,9 +26,9 @@
 
 #pragma once
 
-#include "History.h"
 #include "Image.h"
 #include <LibGUI/Frame.h>
+#include <LibGUI/UndoStack.h>
 #include <LibGfx/Point.h>
 
 namespace PixelPaint {
@@ -108,7 +108,7 @@ private:
 
     RefPtr<Image> m_image;
     RefPtr<Layer> m_active_layer;
-    History m_history;
+    OwnPtr<GUI::UndoStack> m_undo_stack;
 
     Tool* m_active_tool { nullptr };