Add "maintain aspect ratio" in selection transformation (issue #48).

data/gui.xml

@@ -173,6 +173,10 @@
       <!-- When you rotate the selection, pressing this
            keyboard shortcut you activate angle snap -->
       <key action="AngleSnap" shortcut="Shift" />
+
+      <!-- When you scale the selection, pressing this
+           keyboard shortcut you maintain aspect ratio -->
+      <key action="MaintainAspectRatio" shortcut="Shift" />
     </spriteeditor>
 
   </keyboard>

src/modules/editors.cpp

@@ -144,6 +144,14 @@ public:
       return false;
   }
 
+  bool isMaintainAspectRatioKeyPressed() OVERRIDE {
+    JAccel accel = get_accel_to_maintain_aspect_ratio();
+    if (accel)
+      return jaccel_check_from_key(accel);
+    else
+      return false;
+  }
+
 };
 
 class MiniEditor : public Editor

src/modules/gui.cpp

@@ -64,9 +64,10 @@
 
 #define MONITOR_TIMER_MSECS     100
 
-#define SPRITEDITOR_ACTION_COPYSELECTION "CopySelection"
-#define SPRITEDITOR_ACTION_SNAPTOGRID    "SnapToGrid"
-#define SPRITEDITOR_ACTION_ANGLESNAP     "AngleSnap"
+#define SPRITEDITOR_ACTION_COPYSELECTION        "CopySelection"
+#define SPRITEDITOR_ACTION_SNAPTOGRID           "SnapToGrid"
+#define SPRITEDITOR_ACTION_ANGLESNAP            "AngleSnap"
+#define SPRITEDITOR_ACTION_MAINTAINASPECTRATIO  "MaintainAspectRatio"
 
 //////////////////////////////////////////////////////////////////////
 
@@ -959,6 +960,15 @@ JAccel get_accel_to_angle_snap()
     return NULL;
 }
 
+JAccel get_accel_to_maintain_aspect_ratio()
+{
+  Shortcut* shortcut = get_keyboard_shortcut_for_spriteeditor(SPRITEDITOR_ACTION_MAINTAINASPECTRATIO);
+  if (shortcut)
+    return shortcut->accel;
+  else
+    return NULL;
+}
+
 tools::Tool* get_selected_quicktool(tools::Tool* currentTool)
 {
   if (currentTool && currentTool->getInk(0)->isSelection()) {

src/modules/gui.h

@@ -118,6 +118,7 @@ JAccel get_accel_to_change_tool(tools::Tool* tool);
 JAccel get_accel_to_copy_selection();
 JAccel get_accel_to_snap_to_grid();
 JAccel get_accel_to_angle_snap();
+JAccel get_accel_to_maintain_aspect_ratio();
 
 tools::Tool* get_selected_quicktool(tools::Tool* currentTool);
 

src/widgets/editor/editor_customization_delegate.h

@@ -47,6 +47,10 @@ public:
   // Returns true if the user wants to activate angle snap, so he can
   // easily specify common angles (45, 90, 135, 180, etc.).
   virtual bool isAngleSnapKeyPressed() = 0;
+
+  // Returns true if the user wants to maintain the aspect ratio when
+  // he is scaling the selection.
+  virtual bool isMaintainAspectRatioKeyPressed() = 0;
 };
 
 #endif  // WIDGETS_EDITOR_CUSTOMIZATION_DELEGATE_H_INCLUDED

src/widgets/editor/moving_pixels_state.cpp

@@ -187,6 +187,7 @@ bool MovingPixelsState::onMouseMove(Editor* editor, Message* msg)
     int x, y;
     editor->screenToEditor(msg->mouse.x, msg->mouse.y, &x, &y);
 
+    // Get the customization for the pixels movement (snap to grid, angle snap, etc.).
     PixelsMovement::MoveModifier moveModifier = PixelsMovement::NormalMovement;
 
     if (editor->getCustomizationDelegate()->isSnapToGridKeyPressed())
@@ -195,6 +196,9 @@ bool MovingPixelsState::onMouseMove(Editor* editor, Message* msg)
     if (editor->getCustomizationDelegate()->isAngleSnapKeyPressed())
       moveModifier |= PixelsMovement::AngleSnapMovement;
 
+    if (editor->getCustomizationDelegate()->isMaintainAspectRatioKeyPressed())
+      moveModifier |= PixelsMovement::MaintainAspectRatioMovement;
+
     // Drag the image to that position
     gfx::Rect bounds = m_pixelsMovement->moveImage(x, y, moveModifier);
 

src/widgets/editor/pixels_movement.cpp

@@ -197,6 +197,17 @@ gfx::Rect PixelsMovement::moveImage(int x, int y, MoveModifier moveModifier)
     case ScaleNWHandle:
       x1 = MIN(x1+dx, x2-1);
       y1 = MIN(y1+dy, y2-1);
+
+      if ((moveModifier & MaintainAspectRatioMovement) == MaintainAspectRatioMovement) {
+        if (1000 * (x2-x1) / getInitialImageSize().w >
+            1000 * (y2-y1) / getInitialImageSize().h) {
+          y1 = y2 - getInitialImageSize().h * (x2-x1) / getInitialImageSize().w;
+        }
+        else {
+          x1 = x2 - getInitialImageSize().w * (y2-y1) / getInitialImageSize().h;
+        }
+      }
+
       updateBounds = true;
       break;
 
@@ -208,6 +219,17 @@ gfx::Rect PixelsMovement::moveImage(int x, int y, MoveModifier moveModifier)
     case ScaleNEHandle:
       x2 = MAX(x2+dx, x1+1);
       y1 = MIN(y1+dy, y2-1);
+
+      if ((moveModifier & MaintainAspectRatioMovement) == MaintainAspectRatioMovement) {
+        if (1000 * (x2-x1) / getInitialImageSize().w >
+            1000 * (y2-y1) / getInitialImageSize().h) {
+          y1 = y2 - getInitialImageSize().h * (x2-x1) / getInitialImageSize().w;
+        }
+        else {
+          x2 = x1 + getInitialImageSize().w * (y2-y1) / getInitialImageSize().h;
+        }
+      }
+
       updateBounds = true;
       break;
 
@@ -224,6 +246,17 @@ gfx::Rect PixelsMovement::moveImage(int x, int y, MoveModifier moveModifier)
     case ScaleSWHandle:
       x1 = MIN(x1+dx, x2-1);
       y2 = MAX(y2+dy, y1+1);
+
+      if ((moveModifier & MaintainAspectRatioMovement) == MaintainAspectRatioMovement) {
+        if (1000 * (x2-x1) / getInitialImageSize().w >
+            1000 * (y2-y1) / getInitialImageSize().h) {
+          y2 = y1 + getInitialImageSize().h * (x2-x1) / getInitialImageSize().w;
+        }
+        else {
+          x1 = x2 - getInitialImageSize().w * (y2-y1) / getInitialImageSize().h;
+        }
+      }
+
       updateBounds = true;
       break;
 
@@ -235,6 +268,17 @@ gfx::Rect PixelsMovement::moveImage(int x, int y, MoveModifier moveModifier)
     case ScaleSEHandle:
       x2 = MAX(x2+dx, x1+1);
       y2 = MAX(y2+dy, y1+1);
+
+      if ((moveModifier & MaintainAspectRatioMovement) == MaintainAspectRatioMovement) {
+        if (1000 * (x2-x1) / getInitialImageSize().w >
+            1000 * (y2-y1) / getInitialImageSize().h) {
+          y2 = y1 + getInitialImageSize().h * (x2-x1) / getInitialImageSize().w;
+        }
+        else {
+          x2 = x1 + getInitialImageSize().w * (y2-y1) / getInitialImageSize().h;
+        }
+      }
+
       updateBounds = true;
       break;
 

src/widgets/editor/pixels_movement.h

@@ -39,7 +39,8 @@ public:
   enum MoveModifier {
     NormalMovement = 1,
     SnapToGridMovement = 2,
-    AngleSnapMovement = 4
+    AngleSnapMovement = 4,
+    MaintainAspectRatioMovement = 8
   };
 
   // The "moveThis" image specifies the chunk of pixels to be moved.