PixelPaint: Add new selection moving modes

If you press "spacebar" while moving a selection, it will now move the
origin point of the selection; and if you press "control" it will move
it relatively to the center.

Userland/Applications/PixelPaint/RectangleSelectTool.cpp

@@ -37,6 +37,14 @@ void RectangleSelectTool::on_mousemove(Layer&, GUI::MouseEvent&, GUI::MouseEvent
  if (!m_selecting)
  return;
 
+ if (m_moving_mode != MovingMode::None) {
+ auto delta = m_selection_end - image_event.position();
+ if (m_moving_mode == MovingMode::MovingOrigin)
+ m_selection_start -= delta;
+ else if (m_moving_mode == MovingMode::AroundCenter)
+ m_selection_start += delta;
+ }
+
  m_selection_end = image_event.position();
  m_editor->update();
 }
@@ -55,6 +63,22 @@ void RectangleSelectTool::on_mouseup(Layer&, GUI::MouseEvent&, GUI::MouseEvent&
  m_editor->selection().set(rect_in_image);
 }
 
+void RectangleSelectTool::on_keydown(GUI::KeyEvent& key_event)
+{
+ if (key_event.key() == KeyCode::Key_Space)
+ m_moving_mode = MovingMode::MovingOrigin;
+ else if (key_event.key() == KeyCode::Key_Control)
+ m_moving_mode = MovingMode::AroundCenter;
+}
+
+void RectangleSelectTool::on_keyup(GUI::KeyEvent& key_event)
+{
+ if (key_event.key() == KeyCode::Key_Space && m_moving_mode == MovingMode::MovingOrigin)
+ m_moving_mode = MovingMode::None;
+ else if (key_event.key() == KeyCode::Key_Control && m_moving_mode == MovingMode::AroundCenter)
+ m_moving_mode = MovingMode::None;
+}
+
 void RectangleSelectTool::on_second_paint(Layer const&, GUI::PaintEvent& event)
 {
  if (!m_selecting)

Userland/Applications/PixelPaint/RectangleSelectTool.h

@@ -18,10 +18,19 @@ class RectangleSelectTool final : public Tool {
  virtual void on_mousedown(Layer&, GUI::MouseEvent&, GUI::MouseEvent&) override;
  virtual void on_mousemove(Layer&, GUI::MouseEvent&, GUI::MouseEvent&) override;
  virtual void on_mouseup(Layer&, GUI::MouseEvent&, GUI::MouseEvent&) override;
+ virtual void on_keydown(GUI::KeyEvent&) override;
+ virtual void on_keyup(GUI::KeyEvent&) override;
  virtual void on_second_paint(Layer const&, GUI::PaintEvent&) override;
 
 private:
+ enum class MovingMode {
+ MovingOrigin,
+ AroundCenter,
+ None,
+ };
+
  bool m_selecting { false };
+ MovingMode m_moving_mode { MovingMode::None };
  Gfx::IntPoint m_selection_start;
  Gfx::IntPoint m_selection_end;
 };