PaintBrush: Start refactoring to support layer-based images

The main editing widget is now the new ImageEditor widget, which works
on an Image object, which internally has a stack of Layer objects.

Layers are composited back-to-front when painting the Image inside an
ImageEditor.

Applications/PaintBrush/Image.cpp

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * 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 "Image.h"
+#include "Layer.h"
+#include <LibGUI/Painter.h>
+
+namespace PaintBrush {
+
+RefPtr<Image> Image::create_with_size(const Gfx::Size& size)
+{
+    if (size.is_empty())
+        return nullptr;
+
+    if (size.width() > 16384 || size.height() > 16384)
+        return nullptr;
+
+    return adopt(*new Image(size));
+}
+
+Image::Image(const Gfx::Size& size)
+    : m_size(size)
+{
+}
+
+void Image::paint_into(GUI::Painter& painter, const Gfx::Rect& dest_rect, const Gfx::Rect& src_rect)
+{
+    for (auto& layer : m_layers) {
+        auto target = dest_rect.translated(layer.location());
+        dbg() << "Composite layer " << layer.name() << " target: " << target << ", src_rect: " << src_rect;
+        painter.draw_scaled_bitmap(target, layer.bitmap(), src_rect);
+    }
+}
+
+void Image::add_layer(NonnullRefPtr<Layer> layer)
+{
+    for (auto& existing_layer : m_layers) {
+        ASSERT(&existing_layer != layer.ptr());
+    }
+    m_layers.append(move(layer));
+}
+
+}

Applications/PaintBrush/Image.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * 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/NonnullRefPtrVector.h>
+#include <AK/RefCounted.h>
+#include <AK/Vector.h>
+#include <LibGUI/Forward.h>
+#include <LibGfx/Forward.h>
+#include <LibGfx/Rect.h>
+#include <LibGfx/Size.h>
+
+namespace PaintBrush {
+
+class Layer;
+
+class Image : public RefCounted<Image> {
+public:
+    static RefPtr<Image> create_with_size(const Gfx::Size&);
+
+    size_t layer_count() const { return m_layers.size(); }
+    const Layer& layer(size_t index) const { return m_layers.at(index); }
+
+    const Gfx::Size& size() const { return m_size; }
+    Gfx::Rect rect() const { return { {}, m_size }; }
+
+    void add_layer(NonnullRefPtr<Layer>);
+
+    void paint_into(GUI::Painter&, const Gfx::Rect& dest_rect, const Gfx::Rect& src_rect);
+
+private:
+    explicit Image(const Gfx::Size&);
+
+    Gfx::Size m_size;
+    NonnullRefPtrVector<Layer> m_layers;
+};
+
+}

Applications/PaintBrush/ImageEditor.cpp

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * 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 "ImageEditor.h"
+#include "Image.h"
+#include "Layer.h"
+#include <LibGUI/Painter.h>
+#include <LibGfx/Palette.h>
+
+namespace PaintBrush {
+
+ImageEditor::ImageEditor()
+{
+}
+
+void ImageEditor::set_image(RefPtr<Image> image)
+{
+    m_image = move(image);
+    update();
+}
+
+void ImageEditor::paint_event(GUI::PaintEvent& event)
+{
+    GUI::Frame::paint_event(event);
+
+    GUI::Painter painter(*this);
+    painter.add_clip_rect(event.rect());
+
+    painter.fill_rect_with_checkerboard(rect(), { 8, 8 }, palette().base().darkened(0.9), palette().base());
+
+    if (m_image) {
+        m_image->paint_into(painter, m_image->rect(), m_image->rect());
+    }
+}
+
+}

Applications/PaintBrush/ImageEditor.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * 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 <LibGUI/Frame.h>
+
+namespace PaintBrush {
+
+class Image;
+
+class ImageEditor final : public GUI::Frame {
+    C_OBJECT(ImageEditor);
+
+public:
+    const Image* image() const { return m_image; }
+    Image* image() { return m_image; }
+
+    void set_image(RefPtr<Image>);
+
+private:
+    ImageEditor();
+
+    virtual void paint_event(GUI::PaintEvent&) override;
+
+    RefPtr<Image> m_image;
+};
+
+}

Applications/PaintBrush/Layer.cpp

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * 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 "Layer.h"
+#include <LibGfx/Bitmap.h>
+
+namespace PaintBrush {
+
+RefPtr<Layer> Layer::create_with_size(const Gfx::Size& size, const String& name)
+{
+    if (size.is_empty())
+        return nullptr;
+
+    if (size.width() > 16384 || size.height() > 16384)
+        return nullptr;
+
+    return adopt(*new Layer(size, name));
+}
+
+Layer::Layer(const Gfx::Size& size, const String& name)
+    : m_name(name)
+{
+    m_bitmap = Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA32, size);
+}
+
+}

Applications/PaintBrush/Layer.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * 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/Noncopyable.h>
+#include <AK/RefCounted.h>
+#include <AK/String.h>
+#include <LibGfx/Bitmap.h>
+
+namespace PaintBrush {
+
+class Layer : public RefCounted<Layer> {
+    AK_MAKE_NONCOPYABLE(Layer);
+    AK_MAKE_NONMOVABLE(Layer);
+
+public:
+    static RefPtr<Layer> create_with_size(const Gfx::Size&, const String& name);
+
+    ~Layer() {}
+
+    const Gfx::Point& location() const { return m_location; }
+    void set_location(const Gfx::Point& location) { m_location = location; }
+
+    const Gfx::Bitmap& bitmap() const { return *m_bitmap; }
+    Gfx::Bitmap& bitmap() { return *m_bitmap; }
+    Gfx::Size size() const { return bitmap().size(); }
+
+    const String& name() const { return m_name; }
+    void set_name(const String& name) { m_name = name; }
+
+private:
+    explicit Layer(const Gfx::Size&, const String& name);
+
+    String m_name;
+    Gfx::Point m_location;
+    RefPtr<Gfx::Bitmap> m_bitmap;
+};
+
+}

Applications/PaintBrush/Makefile

@@ -1,16 +1,19 @@
 OBJS = \
-    PaintableWidget.o \
-    PaletteWidget.o \
-    ToolboxWidget.o \
-    Tool.o \
-    PenTool.o \
-    LineTool.o \
-    RectangleTool.o \
+    BucketTool.o \
     EllipseTool.o \
     EraseTool.o \
-    BucketTool.o \
-    SprayTool.o \
+    Image.o \
+    ImageEditor.o \
+    Layer.o \
+    LineTool.o \
+    PaintableWidget.o \
+    PaletteWidget.o \
+    PenTool.o \
     PickerTool.o \
+    RectangleTool.o \
+    SprayTool.o \
+    Tool.o \
+    ToolboxWidget.o \
     main.o
 
 PROGRAM = PaintBrush

Applications/PaintBrush/main.cpp

@@ -24,6 +24,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "Image.h"
+#include "ImageEditor.h"
+#include "Layer.h"
 #include "PaintableWidget.h"
 #include "PaletteWidget.h"
 #include "ToolboxWidget.h"
@@ -68,8 +71,12 @@ int main(int argc, char** argv)
     vertical_container.set_layout<GUI::VerticalBoxLayout>();
     vertical_container.layout()->set_spacing(0);
 
+    auto& image_editor = vertical_container.add<PaintBrush::ImageEditor>();
+    image_editor.set_focus(true);
+
     auto& paintable_widget = vertical_container.add<PaintableWidget>();
-    paintable_widget.set_focus(true);
+    paintable_widget.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fixed);
+    paintable_widget.set_preferred_size(0, 0);
     vertical_container.add<PaletteWidget>(paintable_widget);
 
     window->show();
@@ -105,5 +112,23 @@ int main(int argc, char** argv)
 
     app.set_menubar(move(menubar));
 
+    auto image = PaintBrush::Image::create_with_size({ 640, 480 });
+
+    auto bg_layer = PaintBrush::Layer::create_with_size({ 640, 480 }, "Background");
+    image->add_layer(*bg_layer);
+    bg_layer->bitmap().fill(Color::Magenta);
+
+    auto fg_layer_1 = PaintBrush::Layer::create_with_size({ 200, 100 }, "Foreground 1");
+    image->add_layer(*fg_layer_1);
+    fg_layer_1->set_location({ 20, 10 });
+    fg_layer_1->bitmap().fill(Color::Green);
+
+    auto fg_layer_2 = PaintBrush::Layer::create_with_size({ 64, 64 }, "Foreground 2");
+    image->add_layer(*fg_layer_2);
+    fg_layer_2->set_location({ 300, 350 });
+    fg_layer_2->bitmap().fill(Color::Yellow);
+
+    image_editor.set_image(image);
+
     return app.exec();
 }