PaintBrush: Add an erase tool

Applications/PaintBrush/EraseTool.cpp

@@ -0,0 +1,67 @@
+#include "EraseTool.h"
+#include "PaintableWidget.h"
+#include <LibGUI/GAction.h>
+#include <LibGUI/GMenu.h>
+#include <LibGUI/GPainter.h>
+
+EraseTool::EraseTool()
+{
+}
+
+EraseTool::~EraseTool()
+{
+}
+
+Rect EraseTool::build_rect(const Point& pos, const Rect& widget_rect)
+{
+    const int base_eraser_size = 10;
+    const int eraser_size = (base_eraser_size * m_thickness);
+    const int eraser_radius = eraser_size / 2;
+    const auto ex = pos.x();
+    const auto ey = pos.y();
+    return Rect(ex - eraser_radius, ey - eraser_radius, eraser_size, eraser_size).intersected(widget_rect);
+}
+
+void EraseTool::on_mousedown(GMouseEvent& event)
+{
+    if (event.button() != GMouseButton::Left && event.button() != GMouseButton::Right)
+        return;
+    Rect r = build_rect(event.position(), m_widget->bitmap().rect());
+    GPainter painter(m_widget->bitmap());
+    painter.fill_rect(r, Color(Color::White));
+    m_widget->update();
+}
+
+void EraseTool::on_mousemove(GMouseEvent& event)
+{
+    if (!m_widget->rect().contains(event.position()))
+        return;
+
+    if (event.buttons() & GMouseButton::Left || event.buttons() & GMouseButton::Right) {
+        Rect r = build_rect(event.position(), m_widget->bitmap().rect());
+        GPainter painter(m_widget->bitmap());
+        painter.fill_rect(r, Color(Color::White));
+        m_widget->update();
+    }
+}
+
+void EraseTool::on_contextmenu(GContextMenuEvent& event)
+{
+    if (!m_context_menu) {
+        m_context_menu = make<GMenu>("EraseTool Context Menu");
+        m_context_menu->add_action(GAction::create("1", [this](auto&) {
+            m_thickness = 1;
+        }));
+        m_context_menu->add_action(GAction::create("2", [this](auto&) {
+            m_thickness = 2;
+        }));
+        m_context_menu->add_action(GAction::create("3", [this](auto&) {
+            m_thickness = 3;
+        }));
+        m_context_menu->add_action(GAction::create("4", [this](auto&) {
+            m_thickness = 4;
+        }));
+    }
+    m_context_menu->popup(event.screen_position());
+}
+

Applications/PaintBrush/EraseTool.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "Tool.h"
+#include <SharedGraphics/Point.h>
+
+class GMenu;
+
+class EraseTool final : public Tool {
+public:
+    EraseTool();
+    virtual ~EraseTool() override;
+
+    virtual void on_mousedown(GMouseEvent&) override;
+    virtual void on_mousemove(GMouseEvent&) override;
+    virtual void on_contextmenu(GContextMenuEvent&) override;
+
+private:
+    virtual const char* class_name() const override { return "EraseTool"; }
+    Rect build_rect(const Point& pos, const Rect& widget_rect);
+    OwnPtr<GMenu> m_context_menu;
+    int m_thickness { 1 };
+};

Applications/PaintBrush/Makefile

@@ -6,6 +6,7 @@ OBJS = \
     ToolboxWidget.o \
     Tool.o \
     PenTool.o \
+    EraseTool.o \
     BucketTool.o \
     ColorDialog.o \
     SprayTool.o \

Applications/PaintBrush/ToolboxWidget.cpp

@@ -4,6 +4,7 @@
 #include "PaintableWidget.h"
 #include "PenTool.h"
 #include "PickerTool.h"
+#include "EraseTool.h"
 #include <LibGUI/GBoxLayout.h>
 #include <LibGUI/GButton.h>
 #include <SharedGraphics/PNGLoader.h>
@@ -66,6 +67,7 @@ ToolboxWidget::ToolboxWidget(GWidget* parent)
     add_tool("Bucket Fill", "bucket", make<BucketTool>());
     add_tool("Spray", "spray", make<SprayTool>());
     add_tool("Color Picker", "picker", make<PickerTool>());
+    add_tool("Erase", "", make<EraseTool>());
 }
 
 ToolboxWidget::~ToolboxWidget()