PaintBrush: Start working on a simple painting application.

Applications/PaintBrush/PaintableWidget.cpp

@@ -0,0 +1,49 @@
+#include "PaintableWidget.h"
+#include <LibGUI/GPainter.h>
+#include <SharedGraphics/GraphicsBitmap.h>
+
+PaintableWidget::PaintableWidget(GWidget* parent)
+    : GWidget(parent)
+{
+    set_fill_with_background_color(true);
+    set_background_color(Color::LightGray);
+    m_bitmap = GraphicsBitmap::create(GraphicsBitmap::Format::RGB32, { 600, 400 });
+    m_bitmap->fill(Color::White);
+}
+
+PaintableWidget::~PaintableWidget()
+{
+}
+
+void PaintableWidget::paint_event(GPaintEvent& event)
+{
+    GPainter painter(*this);
+    painter.add_clip_rect(event.rect());
+    painter.blit({ 0, 0 }, *m_bitmap, m_bitmap->rect());
+}
+
+void PaintableWidget::mousedown_event(GMouseEvent& event)
+{
+    if (event.button() != GMouseButton::Left)
+        return;
+
+    GPainter painter(*m_bitmap);
+    painter.set_pixel(event.position(), Color::Black);
+    update({ event.position(), { 1, 1 } });
+}
+
+void PaintableWidget::mouseup_event(GMouseEvent&)
+{
+}
+
+void PaintableWidget::mousemove_event(GMouseEvent& event)
+{
+    if (!rect().contains(event.position()))
+        return;
+
+    if (event.buttons() & GMouseButton::Left) {
+        GPainter painter(*m_bitmap);
+        painter.set_pixel(event.position(), Color::Black);
+        update({ event.position(), { 1, 1 } });
+    }
+}