PaintBrush: Add a color picker tool.

Applications/PaintBrush/Makefile

@@ -9,6 +9,7 @@ OBJS = \
     BucketTool.o \
     ColorDialog.o \
     SprayTool.o \
+    PickerTool.o \
     main.o
 
 APP = PaintBrush

Applications/PaintBrush/PaintableWidget.cpp

@@ -72,3 +72,21 @@ void PaintableWidget::mousemove_event(GMouseEvent& event)
     if (m_tool)
         m_tool->on_mousemove(event);
 }
+
+void PaintableWidget::set_primary_color(Color color)
+{
+    if (m_primary_color == color)
+        return;
+    m_primary_color = color;
+    if (on_primary_color_change)
+        on_primary_color_change(color);
+}
+
+void PaintableWidget::set_secondary_color(Color color)
+{
+    if (m_secondary_color == color)
+        return;
+    m_secondary_color = color;
+    if (on_secondary_color_change)
+        on_secondary_color_change(color);
+}

Applications/PaintBrush/PaintableWidget.h

@@ -15,8 +15,8 @@ public:
     Color primary_color() const { return m_primary_color; }
     Color secondary_color() const { return m_secondary_color; }
 
-    void set_primary_color(Color color) { m_primary_color = color; }
+    void set_primary_color(Color);
-    void set_secondary_color(Color color) { m_secondary_color = color; }
+    void set_secondary_color(Color);
 
     void set_tool(Tool* tool);
     Tool* tool();
@@ -26,6 +26,9 @@ public:
     GraphicsBitmap& bitmap() { return *m_bitmap; }
     const GraphicsBitmap& bitmap() const { return *m_bitmap; }
 
+    Function<void(Color)> on_primary_color_change;
+    Function<void(Color)> on_secondary_color_change;
+
 private:
     virtual void paint_event(GPaintEvent&) override;
     virtual void mousedown_event(GMouseEvent&) override;

Applications/PaintBrush/PaletteWidget.cpp

@@ -73,6 +73,14 @@ PaletteWidget::PaletteWidget(PaintableWidget& paintable_widget, GWidget* parent)
     m_primary_color_widget->set_fill_with_background_color(true);
     set_primary_color(paintable_widget.primary_color());
 
+    paintable_widget.on_primary_color_change = [this](Color color) {
+        set_primary_color(color);
+    };
+
+    paintable_widget.on_secondary_color_change = [this](Color color) {
+        set_secondary_color(color);
+    };
+
     auto* color_container = new GWidget(this);
     color_container->set_relative_rect(m_secondary_color_widget->relative_rect().right() + 2, 2, 500, 32);
     color_container->set_layout(make<GBoxLayout>(Orientation::Vertical));

Applications/PaintBrush/PickerTool.cpp

@@ -0,0 +1,22 @@
+#include "PickerTool.h"
+#include <SharedGraphics/GraphicsBitmap.h>
+
+PickerTool::PickerTool()
+{
+}
+
+PickerTool::~PickerTool()
+{
+}
+
+void PickerTool::on_mousedown(GMouseEvent& event)
+{
+    ASSERT(m_widget);
+    if (!m_widget->bitmap().rect().contains(event.position()))
+        return;
+    auto color = m_widget->bitmap().get_pixel(event.position());
+    if (event.button() == GMouseButton::Left)
+        m_widget->set_primary_color(color);
+    else if (event.button() == GMouseButton::Right)
+        m_widget->set_secondary_color(color);
+}

Applications/PaintBrush/PickerTool.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include "Tool.h"
+
+class PickerTool final : public Tool {
+public:
+    PickerTool();
+    virtual ~PickerTool() override;
+
+    virtual void on_mousedown(GMouseEvent&) override;
+
+private:
+    virtual const char* class_name() const override { return "PickerTool"; }
+
+};

Applications/PaintBrush/ToolboxWidget.cpp

@@ -3,6 +3,7 @@
 #include "SprayTool.h"
 #include "PaintableWidget.h"
 #include "PenTool.h"
+#include "PickerTool.h"
 #include <LibGUI/GBoxLayout.h>
 #include <LibGUI/GButton.h>
 #include <SharedGraphics/PNGLoader.h>
@@ -59,6 +60,7 @@ ToolboxWidget::ToolboxWidget(GWidget* parent)
     add_tool("Pen", "pen", make<PenTool>());
     add_tool("Bucket Fill", "bucket", make<BucketTool>());
     add_tool("Spray", "spray", make<SprayTool>());
+    add_tool("Color Picker", "picker", make<PickerTool>());
 }
 
 ToolboxWidget::~ToolboxWidget()