PixelPaint: Scale layer and preserve aspect ratio

This patch adds the ability to scale a layer and
preserve the aspect ratio.
When the Shift key is pressed, the aspect ratio is preserved.

Userland/Applications/PixelPaint/Tools/MoveTool.cpp

@@ -11,6 +11,7 @@
 #include "../Layer.h"
 #include <LibGUI/Action.h>
 #include <LibGUI/Menu.h>
+#include <LibGUI/Painter.h>
 #include <LibGUI/Window.h>
 
 namespace PixelPaint {
@@ -56,6 +57,22 @@ void MoveTool::on_mousemove(Layer* layer, MouseEvent& event)
         m_editor->update_tool_cursor();
     }
 
+    if (m_scaling) {
+        auto& cursor_location = event.image_event().position();
+        auto width = abs(m_layer_being_moved->location().x() - cursor_location.x());
+        auto height = abs(m_layer_being_moved->location().y() - cursor_location.y());
+        if (m_keep_ascept_ratio) {
+            if (abs(width - m_layer_being_moved->size().width()) > abs(height - m_layer_being_moved->size().height())) {
+                height = width * m_layer_being_moved->size().height() / m_layer_being_moved->size().width();
+            } else {
+                width = height * m_layer_being_moved->size().width() / m_layer_being_moved->size().height();
+            }
+        }
+        m_new_layer_size = Gfx::IntSize(width, height);
+        // TODO: Change this according to which direction the user is scaling
+        m_new_scaled_layer_location = Gfx::IntPoint(m_layer_being_moved->location().x(), m_layer_being_moved->location().y());
+    }
+
     auto& image_event = event.image_event();
     if (!m_layer_being_moved || m_scaling)
         return;
@@ -80,21 +97,20 @@ void MoveTool::on_mouseup(Layer* layer, MouseEvent& event)
         return;
 
     if (m_scaling) {
-        auto& cursor_location = event.image_event().position();
-
-        auto new_size = Gfx::IntSize(abs(m_layer_being_moved->location().x() - cursor_location.x()), abs(m_layer_being_moved->location().y() - cursor_location.y()));
-        // TODO: Change this according to which direction the user is scaling
-        auto new_location = Gfx::IntPoint(m_layer_being_moved->location().x(), m_layer_being_moved->location().y());
-        m_editor->active_layer()->resize(new_size, new_location, Gfx::Painter::ScalingMode::BilinearBlend);
+        m_editor->active_layer()->resize(m_new_layer_size, m_new_scaled_layer_location, Gfx::Painter::ScalingMode::BilinearBlend);
     }
 
     m_scaling = false;
     m_layer_being_moved = nullptr;
+    m_editor->update_tool_cursor();
     m_editor->did_complete_action(tool_name());
 }
 
 void MoveTool::on_keydown(GUI::KeyEvent& event)
 {
+    if (event.key() == Key_Shift)
+        m_keep_ascept_ratio = true;
+
     if (m_scaling)
         return;
 
@@ -128,6 +144,12 @@ void MoveTool::on_keydown(GUI::KeyEvent& event)
     m_editor->layers_did_change();
 }
 
+void MoveTool::on_keyup(GUI::KeyEvent& event)
+{
+    if (event.key() == Key_Shift)
+        m_keep_ascept_ratio = false;
+}
+
 Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> MoveTool::cursor()
 {
     if (m_mouse_in_resize_corner || m_scaling)

Userland/Applications/PixelPaint/Tools/MoveTool.h

@@ -21,6 +21,7 @@ public:
     virtual void on_mousemove(Layer*, MouseEvent&) override;
     virtual void on_mouseup(Layer*, MouseEvent&) override;
     virtual void on_keydown(GUI::KeyEvent&) override;
+    virtual void on_keyup(GUI::KeyEvent&) override;
     virtual Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> cursor() override;
 
 private:
@@ -29,8 +30,11 @@ private:
     RefPtr<Layer> m_layer_being_moved;
     Gfx::IntPoint m_event_origin;
     Gfx::IntPoint m_layer_origin;
+    Gfx::IntPoint m_new_scaled_layer_location;
+    Gfx::IntSize m_new_layer_size;
     bool m_scaling { false };
     bool m_mouse_in_resize_corner { false };
+    bool m_keep_ascept_ratio { false };
 };
 
 }