PaintBrush: Factor out the pen tool into an actual PenTool class.

Also add a Tool base class, and an empty BucketTool subclass which is the
next thing to implement.

Applications/PaintBrush/BucketTool.cpp

@@ -0,0 +1,15 @@
+#include "BucketTool.h"
+#include <stdio.h>
+
+BucketTool::BucketTool()
+{
+}
+
+BucketTool::~BucketTool()
+{
+}
+
+void BucketTool::on_mousedown(PaintableWidget&, GMouseEvent&)
+{
+    dbgprintf("FIXME: Implement BucketTool::on_mousedown\n");
+}

Applications/PaintBrush/BucketTool.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "Tool.h"
+
+class BucketTool final : public Tool {
+public:
+    BucketTool();
+    virtual ~BucketTool() override;
+
+    virtual void on_mousedown(PaintableWidget&, GMouseEvent&) override;
+
+private:
+    virtual const char* class_name() const override { return "BucketTool"; }
+};

Applications/PaintBrush/Makefile

@@ -4,6 +4,9 @@ OBJS = \
     PaintableWidget.o \
     PaletteWidget.o \
     ToolboxWidget.o \
+    Tool.o \
+    PenTool.o \
+    BucketTool.o \
     main.o
 
 APP = PaintBrush

Applications/PaintBrush/PaintableWidget.cpp

@@ -1,10 +1,20 @@
 #include "PaintableWidget.h"
+#include "Tool.h"
 #include <LibGUI/GPainter.h>
 #include <SharedGraphics/GraphicsBitmap.h>
 
+static PaintableWidget* s_the;
+
+PaintableWidget& PaintableWidget::the()
+{
+    return *s_the;
+}
+
 PaintableWidget::PaintableWidget(GWidget* parent)
     : GWidget(parent)
 {
+    ASSERT(!s_the);
+    s_the = this;
     set_fill_with_background_color(true);
     set_background_color(Color::MidGray);
     m_bitmap = GraphicsBitmap::create(GraphicsBitmap::Format::RGB32, { 600, 400 });
@@ -33,37 +43,18 @@ Color PaintableWidget::color_for(const GMouseEvent& event)
 
 void PaintableWidget::mousedown_event(GMouseEvent& event)
 {
-    if (event.button() != GMouseButton::Left && event.button() != GMouseButton::Right)
-        return;
-
-    GPainter painter(*m_bitmap);
-    painter.set_pixel(event.position(), color_for(event));
-    update({ event.position(), { 1, 1 } });
-    m_last_drawing_event_position = event.position();
+    if (m_tool)
+        m_tool->on_mousedown(*this, event);
 }
 
 void PaintableWidget::mouseup_event(GMouseEvent& event)
 {
-    if (event.button() == GMouseButton::Left || event.button() == GMouseButton::Right)
-        m_last_drawing_event_position = { -1, -1 };
+    if (m_tool)
+        m_tool->on_mouseup(*this, event);
 }
 
 void PaintableWidget::mousemove_event(GMouseEvent& event)
 {
-    if (!rect().contains(event.position()))
-        return;
-
-    if (event.buttons() & GMouseButton::Left || event.buttons() & GMouseButton::Right) {
-        GPainter painter(*m_bitmap);
-
-        if (m_last_drawing_event_position != Point(-1, -1)) {
-            painter.draw_line(m_last_drawing_event_position, event.position(), color_for(event));
-            update();
-        } else {
-            painter.set_pixel(event.position(), color_for(event));
-            update({ event.position(), { 1, 1 } });
-        }
-
-        m_last_drawing_event_position = event.position();
-    }
+    if (m_tool)
+        m_tool->on_mousemove(*this, event);
 }

Applications/PaintBrush/PaintableWidget.h

@@ -2,8 +2,12 @@
 
 #include <LibGUI/GWidget.h>
 
+class Tool;
+
 class PaintableWidget final : public GWidget {
 public:
+    static PaintableWidget& the();
+
     explicit PaintableWidget(GWidget* parent);
     virtual ~PaintableWidget() override;
 
@@ -15,17 +19,24 @@ public:
     void set_primary_color(Color color) { m_primary_color = color; }
     void set_secondary_color(Color color) { m_secondary_color = color; }
 
+    void set_tool(Tool* tool) { m_tool = tool; }
+    Tool* tool() { return m_tool; }
+
+    Color color_for(const GMouseEvent&);
+
+    GraphicsBitmap& bitmap() { return *m_bitmap; }
+    const GraphicsBitmap& bitmap() const { return *m_bitmap; }
+
 private:
     virtual void paint_event(GPaintEvent&) override;
     virtual void mousedown_event(GMouseEvent&) override;
     virtual void mouseup_event(GMouseEvent&) override;
     virtual void mousemove_event(GMouseEvent&) override;
 
-    Color color_for(const GMouseEvent&);
-
-    Point m_last_drawing_event_position { -1, -1 };
     RetainPtr<GraphicsBitmap> m_bitmap;
 
     Color m_primary_color { Color::Black };
     Color m_secondary_color { Color::White };
+
+    Tool* m_tool { nullptr };
 };

Applications/PaintBrush/PenTool.cpp

@@ -0,0 +1,48 @@
+#include "PenTool.h"
+#include "PaintableWidget.h"
+#include <LibGUI/GPainter.h>
+
+PenTool::PenTool()
+{
+}
+
+PenTool::~PenTool()
+{
+}
+
+void PenTool::on_mousedown(PaintableWidget& paintable_widget, GMouseEvent& event)
+{
+    if (event.button() != GMouseButton::Left && event.button() != GMouseButton::Right)
+        return;
+
+    GPainter painter(paintable_widget.bitmap());
+    painter.set_pixel(event.position(), paintable_widget.color_for(event));
+    paintable_widget.update({ event.position(), { 1, 1 } });
+    m_last_drawing_event_position = event.position();
+}
+
+void PenTool::on_mouseup(PaintableWidget&, GMouseEvent& event)
+{
+    if (event.button() == GMouseButton::Left || event.button() == GMouseButton::Right)
+        m_last_drawing_event_position = { -1, -1 };
+}
+
+void PenTool::on_mousemove(PaintableWidget& paintable_widget, GMouseEvent& event)
+{
+    if (!paintable_widget.rect().contains(event.position()))
+        return;
+
+    if (event.buttons() & GMouseButton::Left || event.buttons() & GMouseButton::Right) {
+        GPainter painter(paintable_widget.bitmap());
+
+        if (m_last_drawing_event_position != Point(-1, -1)) {
+            painter.draw_line(m_last_drawing_event_position, event.position(), paintable_widget.color_for(event));
+            paintable_widget.update();
+        } else {
+            painter.set_pixel(event.position(), paintable_widget.color_for(event));
+            paintable_widget.update({ event.position(), { 1, 1 } });
+        }
+
+        m_last_drawing_event_position = event.position();
+    }
+}

Applications/PaintBrush/PenTool.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "Tool.h"
+#include <SharedGraphics/Point.h>
+
+class PenTool final : public Tool {
+public:
+    PenTool();
+    virtual ~PenTool() override;
+
+    virtual void on_mousedown(PaintableWidget&, GMouseEvent&) override;
+    virtual void on_mousemove(PaintableWidget&, GMouseEvent&) override;
+    virtual void on_mouseup(PaintableWidget&, GMouseEvent&) override;
+
+private:
+    virtual const char* class_name() const override { return "PenTool"; }
+
+    Point m_last_drawing_event_position { -1, -1 };
+};

Applications/PaintBrush/Tool.cpp

@@ -0,0 +1,9 @@
+#include "Tool.h"
+
+Tool::Tool()
+{
+}
+
+Tool::~Tool()
+{
+}

Applications/PaintBrush/Tool.h

@@ -0,0 +1,18 @@
+#pragma once
+
+class GMouseEvent;
+class PaintableWidget;
+
+class Tool {
+public:
+    virtual ~Tool();
+
+    virtual const char* class_name() const = 0;
+
+    virtual void on_mousedown(PaintableWidget&, GMouseEvent&) { }
+    virtual void on_mousemove(PaintableWidget&, GMouseEvent&) { }
+    virtual void on_mouseup(PaintableWidget&, GMouseEvent&) { }
+
+protected:
+    Tool();
+};

Applications/PaintBrush/ToolboxWidget.cpp

@@ -1,7 +1,25 @@
 #include "ToolboxWidget.h"
+#include "BucketTool.h"
+#include "PaintableWidget.h"
+#include "PenTool.h"
 #include <LibGUI/GBoxLayout.h>
 #include <LibGUI/GButton.h>
 
+class ToolButton final : public GButton {
+public:
+    ToolButton(const String& name, GWidget* parent, OwnPtr<Tool>&& tool)
+        : GButton(name, parent)
+        , m_tool(move(tool))
+    {
+    }
+
+    const Tool& tool() const { return *m_tool; }
+    Tool& tool() { return *m_tool; }
+
+private:
+    OwnPtr<Tool> m_tool;
+};
+
 ToolboxWidget::ToolboxWidget(GWidget* parent)
     : GFrame(parent)
 {
@@ -18,17 +36,23 @@ ToolboxWidget::ToolboxWidget(GWidget* parent)
     set_layout(make<GBoxLayout>(Orientation::Vertical));
     layout()->set_margins({ 4, 4, 4, 4 });
 
-    auto add_tool = [&] (const StringView& name) {
-        auto* button = new GButton(name, this);
+    auto add_tool = [&](const StringView& name, OwnPtr<Tool>&& tool) {
+        auto* button = new ToolButton(name, this, move(tool));
         button->set_size_policy(SizePolicy::Fill, SizePolicy::Fixed);
         button->set_preferred_size({ 0, 32 });
         button->set_checkable(true);
         button->set_exclusive(true);
+
+        button->on_checked = [button](auto checked) {
+            if (checked)
+                PaintableWidget::the().set_tool(&button->tool());
+            else
+                PaintableWidget::the().set_tool(nullptr);
+        };
     };
 
-    add_tool("Pen");
-    add_tool("Buck");
-    add_tool("Pick");
+    add_tool("Pen", make<PenTool>());
+    add_tool("Buck", make<BucketTool>());
 }
 
 ToolboxWidget::~ToolboxWidget()