Add xor-ed bounding box in SelectBoxState when QUICKBOX style is enabled

This is useful when we want to select a brush in a black image (the
DARKOUTSIDE style is not useful in this case).

src/app/ui/editor/editor.cpp

@@ -99,17 +99,14 @@ class EditorPostRenderImpl : public EditorPostRender {
 public:
   EditorPostRenderImpl(Editor* editor, Graphics* g)
     : m_editor(editor)
-    , m_g(g)
-  {
+    , m_g(g) {
   }
 
-  Editor* getEditor()
-  {
+  Editor* getEditor() {
     return m_editor;
   }
 
-  void drawLine(int x1, int y1, int x2, int y2, gfx::Color screenColor)
-  {
+  void drawLine(int x1, int y1, int x2, int y2, gfx::Color screenColor) override {
     gfx::Point a(x1, y1);
     gfx::Point b(x2, y2);
     a = m_editor->editorToScreen(a);
@@ -122,6 +119,17 @@ public:
     m_g->drawLine(screenColor, a, b);
   }
 
+  void drawRectXor(const gfx::Rect& rc) override {
+    gfx::Rect rc2 = m_editor->editorToScreen(rc);
+    gfx::Rect bounds = m_editor->getBounds();
+    rc2.x -= bounds.x;
+    rc2.y -= bounds.y;
+
+    m_g->setDrawMode(Graphics::DrawMode::Xor);
+    m_g->drawRect(gfx::rgba(255, 255, 255), rc2);
+    m_g->setDrawMode(Graphics::DrawMode::Solid);
+  }
+
 private:
   Editor* m_editor;
   Graphics* m_g;

src/app/ui/editor/editor_decorator.h

@@ -38,6 +38,7 @@ namespace app {
     virtual ~EditorPostRender() { }
     virtual Editor* getEditor() = 0;
     virtual void drawLine(int x1, int y1, int x2, int y2, gfx::Color screenColor) = 0;
+    virtual void drawRectXor(const gfx::Rect& rc) = 0;
   };
 
   // Used by editor's states to pre- and post-render customized

src/app/ui/editor/select_box_state.cpp

@@ -263,6 +263,10 @@ void SelectBoxState::postRenderDecorator(EditorPostRender* render)
       }
     }
   }
+
+  if (hasFlag(QUICKBOX)) {
+    render->drawRectXor(getBoxBounds());
+  }
 }
 
 bool SelectBoxState::touchRuler(Editor* editor, Ruler& ruler, int x, int y)

src/she/alleg4/surface.h

@@ -161,6 +161,7 @@ namespace she {
     void setDrawMode(DrawMode mode, int param) {
       switch (mode) {
         case DrawMode::Solid: checked_mode(-1); break;
+        case DrawMode::Xor: xor_mode(TRUE); break;
         case DrawMode::Checked: checked_mode(param); break;
       }
     }

src/she/surface.h

@@ -1,5 +1,5 @@
 // SHE library
-// Copyright (C) 2012-2013  David Capello
+// Copyright (C) 2012-2013, 2015  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -16,7 +16,8 @@ namespace she {
 
   enum class DrawMode {
     Solid,
-    Checked
+    Checked,
+    Xor
   };
 
   class Surface {

src/ui/graphics.cpp

@@ -67,6 +67,9 @@ void Graphics::setDrawMode(DrawMode mode, int param)
     case DrawMode::Solid:
       m_surface->setDrawMode(she::DrawMode::Solid);
       break;
+    case DrawMode::Xor:
+      m_surface->setDrawMode(she::DrawMode::Xor);
+      break;
     case DrawMode::Checked:
       m_surface->setDrawMode(she::DrawMode::Checked, param);
       break;

src/ui/graphics.h

@@ -33,6 +33,7 @@ namespace ui {
   public:
     enum class DrawMode {
       Solid,
+      Xor,
       Checked,
     };