Refactor|libappfw: Animating procedural images, fold panel indicator

If a procedural image is animating, it will return indication of
that from its update() method.

The fold panel indicator now turns 90 degrees with an animation
depending on whether the fold is open or closed.

doomsday/libappfw/include/de/framework/atlasproceduralimage.h

@@ -79,13 +79,15 @@ class LIBAPPFW_PUBLIC AtlasProceduralImage : public ProceduralImage
         setSize(image.size());
     }
 
-    void update()
+    bool update()
     {
         if(_needUpdate)
         {
             alloc();
             _needUpdate = false;
+            return true;
         }
+        return false;
     }
 
     void glInit()

doomsday/libappfw/include/de/framework/proceduralimage.h

@@ -49,7 +49,14 @@ class LIBAPPFW_PUBLIC ProceduralImage
     void setSize(Size const &size);
     void setColor(Color const &color);
 
-    virtual void update();
+    /**
+     * Updates the image.
+     *
+     * @return @c true, if the geometry has changed and it should be remade. Otherwise
+     * @c false if nothing has been changed.
+     */
+    virtual bool update();
+
     virtual void glInit();
     virtual void glDeinit();
     virtual void glMakeGeometry(DefaultVertexBuf::Builder &verts, Rectanglef const &rect) = 0;

doomsday/libappfw/include/de/framework/styleproceduralimage.h

@@ -49,8 +49,6 @@ class StyleProceduralImage : public ProceduralImage
         setSize(root().atlas().imageRect(_id).size());
     }
 
-    void update() {}
-
     void glInit()
     {
         alloc();

doomsday/libappfw/src/proceduralimage.cpp

@@ -46,9 +46,10 @@ void ProceduralImage::setColor(Color const &color)
     _color = color;
 }
 
-void ProceduralImage::update()
+bool ProceduralImage::update()
 {
     // optional for derived classes
+    return false;
 }
 
 void ProceduralImage::glInit()

doomsday/libappfw/src/widgets/foldpanelwidget.cpp

@@ -27,18 +27,53 @@ using namespace ui;
 
 DENG2_PIMPL_NOREF(FoldPanelWidget)
 {
+    /**
+     * Indicator that shows whether a fold panel is open or closed.
+     */
     struct FoldImage : public ProceduralImage
     {
         FoldPanelWidget &fold;
-        bool needUpdate;
-
-        FoldImage(FoldPanelWidget &owner) : fold(owner), needUpdate(true)
+        bool needSize;
+        bool animating;
+        Animation angle;
+
+        FoldImage(FoldPanelWidget &owner)
+            : fold(owner)
+            , needSize(true)
+            , animating(false)
+            , angle(0, Animation::EaseBoth)
         {}
 
-        void update()
+        /// We'll report the status as changed if the image was animating or its
+        /// size was updated.
+        bool update()
         {
-            float h = fold.title().font().height().value();
-            setSize(Vector2f(h, h));
+            bool changed = animating;
+
+            float target = (fold.isOpen()? 0 : 90);
+            if(target != angle.target())
+            {
+                angle.setValue(target, 1);
+                animating = true;
+                changed = true;
+            }
+
+            if(needSize)
+            {
+                needSize = false;
+                changed = true;
+
+                float h = fold.title().font().height().value();
+                setSize(Vector2f(h, h));
+            }
+
+            // Stop animating?
+            if(animating && angle.done())
+            {
+                animating = false;
+            }
+
+            return changed;
         }
 
         void glMakeGeometry(DefaultVertexBuf::Builder &verts, Rectanglef const &rect)
@@ -47,16 +82,13 @@ DENG2_PIMPL_NOREF(FoldPanelWidget)
             Atlas &atlas = root.atlas();
             ColorBank::Colorf const &textColor = fold.title().textColorf();
 
+            // Frame.
             verts.makeFlexibleFrame(rect.toRectanglei(), 5, textColor,
                                     atlas.imageRectf(root.roundCorners()));
 
             Rectanglef uv = atlas.imageRectf(root.styleTexture("fold"));
-            if(!fold.isOpen())
-            {
-                // Flip it.
-                uv = Rectanglef(uv.bottomLeft(), uv.topRight());
-            }
-            verts.makeQuad(rect, textColor * Vector4f(1, 1, 1, .5f), uv);
+            Matrix4f const turn = Matrix4f::rotateAround(rect.middle(), angle);
+            verts.makeQuad(rect, textColor * Vector4f(1, 1, 1, .5f), uv, &turn);
         }
     };
 

doomsday/libappfw/src/widgets/labelwidget.cpp

@@ -483,13 +483,13 @@ public Font::RichFormat::IStyle
     void updateGeometry()
     {
         // Update the image on the atlas.
-        if(!image.isNull())
+        if(!image.isNull() && image->update())
         {
-            image->update();
+            self.requestGeometry();
         }
-        if(!overlayImage.isNull())
+        if(!overlayImage.isNull() && overlayImage->update())
         {
-            overlayImage->update();
+            self.requestGeometry();
         }
 
         glText.setLineWrapWidth(availableTextWidth());

doomsday/libappfw/src/widgets/togglewidget.cpp

@@ -51,13 +51,14 @@ DENG2_OBSERVES(ButtonWidget, Press)
             _animating = true;
         }
 
-        void update()
+        bool update()
         {
             if(_animating)
             {
-                _owner.requestGeometry();
                 if(_pos.done()) _animating = false;
+                return true;
             }
+            return false;
         }
 
         void glMakeGeometry(DefaultVertexBuf::Builder &verts, Rectanglef const &rect)