Fixes to deal with effect rendering in retina displays, e.g. drop-shadows, etc.

modules/juce_graphics/contexts/juce_LowLevelGraphicsContext.h

@@ -69,6 +69,8 @@ public:
     virtual void addTransform (const AffineTransform& transform) = 0;
     virtual float getScaleFactor() = 0;
 
+    virtual float getTargetDeviceScaleFactor()    { return 1.0f; }
+
     virtual bool clipToRectangle (const Rectangle<int>& r) = 0;
     virtual bool clipToRectangleList (const RectangleList& clipRegion) = 0;
     virtual void excludeClipRectangle (const Rectangle<int>& r) = 0;

modules/juce_graphics/effects/juce_DropShadowEffect.cpp

@@ -51,52 +51,57 @@ void DropShadowEffect::setShadowProperties (const float newRadius,
     opacity = newOpacity;
 }
 
-void DropShadowEffect::applyEffect (Image& image, Graphics& g, float alpha)
+void DropShadowEffect::drawShadow (Graphics& g, const Image& srcImage,
+                                   float radius, float alpha, int offsetX, int offsetY)
 {
-    const int w = image.getWidth();
-    const int h = image.getHeight();
+    const int w = srcImage.getWidth();
+    const int h = srcImage.getHeight();
 
     Image shadowImage (Image::SingleChannel, w, h, false);
 
+    const Image::BitmapData srcData (srcImage, Image::BitmapData::readOnly);
+    const Image::BitmapData destData (shadowImage, Image::BitmapData::readWrite);
+
+    const int filter = roundToInt (63.0f / radius);
+    const int radiusMinus1 = roundToInt ((radius - 1.0f) * 63.0f);
+
+    for (int x = w; --x >= 0;)
     {
-        const Image::BitmapData srcData (image, Image::BitmapData::readOnly);
-        const Image::BitmapData destData (shadowImage, Image::BitmapData::readWrite);
+        int shadowAlpha = 0;
 
-        const int filter = roundToInt (63.0f / radius);
-        const int radiusMinus1 = roundToInt ((radius - 1.0f) * 63.0f);
-
-        for (int x = w; --x >= 0;)
-        {
-            int shadowAlpha = 0;
-
-            const PixelARGB* src = ((const PixelARGB*) srcData.data) + x;
-            uint8* shadowPix = destData.data + x;
-
-            for (int y = h; --y >= 0;)
-            {
-                shadowAlpha = ((shadowAlpha * radiusMinus1 + (src->getAlpha() << 6)) * filter) >> 12;
-
-                *shadowPix = (uint8) shadowAlpha;
-                src = addBytesToPointer (src, srcData.lineStride);
-                shadowPix += destData.lineStride;
-            }
-        }
+        const PixelARGB* src = ((const PixelARGB*) srcData.data) + x;
+        uint8* shadowPix = destData.data + x;
 
         for (int y = h; --y >= 0;)
         {
-            int shadowAlpha = 0;
-            uint8* shadowPix = destData.getLinePointer (y);
+            shadowAlpha = ((shadowAlpha * radiusMinus1 + (src->getAlpha() << 6)) * filter) >> 12;
 
-            for (int x = w; --x >= 0;)
-            {
-                shadowAlpha = ((shadowAlpha * radiusMinus1 + (*shadowPix << 6)) * filter) >> 12;
-                *shadowPix++ = (uint8) shadowAlpha;
-            }
+            *shadowPix = (uint8) shadowAlpha;
+            src = addBytesToPointer (src, srcData.lineStride);
+            shadowPix += destData.lineStride;
         }
     }
 
-    g.setColour (Colours::black.withAlpha (opacity * alpha));
+    for (int y = h; --y >= 0;)
+    {
+        int shadowAlpha = 0;
+        uint8* shadowPix = destData.getLinePointer (y);
+
+        for (int x = w; --x >= 0;)
+        {
+            shadowAlpha = ((shadowAlpha * radiusMinus1 + (*shadowPix << 6)) * filter) >> 12;
+            *shadowPix++ = (uint8) shadowAlpha;
+        }
+    }
+
+    g.setColour (Colours::black.withAlpha (alpha));
     g.drawImageAt (shadowImage, offsetX, offsetY, true);
+}
+
+void DropShadowEffect::applyEffect (Image& image, Graphics& g, float scaleFactor, float alpha)
+{
+    drawShadow (g, image, radius * scaleFactor, opacity * alpha,
+                (int) (offsetX * scaleFactor), (int) (offsetY * scaleFactor));
 
     g.setOpacity (alpha);
     g.drawImageAt (image, 0, 0);

modules/juce_graphics/effects/juce_DropShadowEffect.h

@@ -75,9 +75,12 @@ public:
                               int newShadowOffsetY);
 
 
+    static void drawShadow (Graphics& g, const Image& srcImage,
+                            float radius, float alpha, int offsetX, int offsetY);
+
     //==============================================================================
     /** @internal */
-    void applyEffect (Image& sourceImage, Graphics& destContext, float alpha);
+    void applyEffect (Image& sourceImage, Graphics& destContext, float scaleFactor, float alpha);
 
 
 private:

modules/juce_graphics/effects/juce_GlowEffect.cpp

@@ -40,11 +40,11 @@ void GlowEffect::setGlowProperties (const float newRadius,
     colour = newColour;
 }
 
-void GlowEffect::applyEffect (Image& image, Graphics& g, float alpha)
+void GlowEffect::applyEffect (Image& image, Graphics& g, float scaleFactor, float alpha)
 {
     Image temp (image.getFormat(), image.getWidth(), image.getHeight(), true);
 
-    ImageConvolutionKernel blurKernel (roundToInt (radius * 2.0f));
+    ImageConvolutionKernel blurKernel (roundToInt (radius * scaleFactor * 2.0f));
 
     blurKernel.createGaussianBlur (radius);
     blurKernel.rescaleAllValues (radius);

modules/juce_graphics/effects/juce_GlowEffect.h

@@ -63,7 +63,7 @@ public:
 
     //==============================================================================
     /** @internal */
-    void applyEffect (Image& sourceImage, Graphics& destContext, float alpha);
+    void applyEffect (Image& sourceImage, Graphics& destContext, float scaleFactor, float alpha);
 
 private:
     //==============================================================================

modules/juce_graphics/effects/juce_ImageEffectFilter.h

@@ -53,11 +53,15 @@ public:
                                 its paint() method. The image may or may not have an alpha
                                 channel, depending on whether the component is opaque.
         @param destContext      the graphics context to use to draw the resultant image.
+        @param scaleFactor      a scale factor that has been applied to the image - e.g. if
+                                this is 2, then the image is actually scaled-up to twice the
+                                original resolution
         @param alpha            the alpha with which to draw the resultant image to the
                                 target context
     */
     virtual void applyEffect (Image& sourceImage,
                               Graphics& destContext,
+                              float scaleFactor,
                               float alpha) = 0;
 
     /** Destructor. */

modules/juce_graphics/native/juce_mac_CoreGraphicsContext.h

@@ -30,7 +30,7 @@
 class CoreGraphicsContext   : public LowLevelGraphicsContext
 {
 public:
-    CoreGraphicsContext (CGContextRef context_, const float flipHeight_);
+    CoreGraphicsContext (CGContextRef context_, const float flipHeight_, const float targetScale_);
     ~CoreGraphicsContext();
 
     //==============================================================================
@@ -39,6 +39,7 @@ public:
     void setOrigin (int x, int y);
     void addTransform (const AffineTransform& transform);
     float getScaleFactor();
+    float getTargetDeviceScaleFactor()  { return targetScale; }
     bool clipToRectangle (const Rectangle<int>& r);
     bool clipToRectangleList (const RectangleList& clipRegion);
     void excludeClipRectangle (const Rectangle<int>& r);
@@ -77,6 +78,7 @@ public:
 private:
     CGContextRef context;
     const CGFloat flipHeight;
+    float targetScale;
     CGColorSpaceRef rgbColourSpace, greyColourSpace;
     CGFunctionCallbacks gradientCallbacks;
     mutable Rectangle<int> lastClipRect;

modules/juce_graphics/native/juce_mac_CoreGraphicsContext.mm

@@ -53,7 +53,7 @@ public:
 
     LowLevelGraphicsContext* createLowLevelContext()
     {
-        return new CoreGraphicsContext (context, height);
+        return new CoreGraphicsContext (context, height, 1.0f);
     }
 
     void initialiseBitmapData (Image::BitmapData& bitmap, int x, int y, Image::BitmapData::ReadWriteMode)
@@ -124,9 +124,10 @@ ImagePixelData* NativeImageType::create (Image::PixelFormat format, int width, i
 }
 
 //==============================================================================
-CoreGraphicsContext::CoreGraphicsContext (CGContextRef context_, const float flipHeight_)
+CoreGraphicsContext::CoreGraphicsContext (CGContextRef context_, const float flipHeight_, const float targetScale_)
     : context (context_),
       flipHeight (flipHeight_),
+      targetScale (targetScale_),
       lastClipRectIsValid (false),
       state (new SavedState())
 {

modules/juce_gui_basics/components/juce_Component.cpp

@@ -1946,14 +1946,20 @@ void Component::paintEntireComponent (Graphics& g, const bool ignoreAlphaLevel)
 
     if (effect != nullptr)
     {
+        const float scale = g.getInternalContext()->getTargetDeviceScaleFactor();
+
         Image effectImage (flags.opaqueFlag ? Image::RGB : Image::ARGB,
-                           getWidth(), getHeight(), ! flags.opaqueFlag);
+                           (int) (scale * getWidth()), (int) (scale * getHeight()), ! flags.opaqueFlag);
         {
             Graphics g2 (effectImage);
+            g2.addTransform (AffineTransform::scale (scale, scale));
             paintComponentAndChildren (g2);
         }
 
-        effect->applyEffect (effectImage, g, ignoreAlphaLevel ? 1.0f : getAlpha());
+        g.saveState();
+        g.addTransform (AffineTransform::scale (1.0f / scale, 1.0f / scale));
+        effect->applyEffect (effectImage, g, scale, ignoreAlphaLevel ? 1.0f : getAlpha());
+        g.restoreState();
     }
     else if (componentTransparency > 0 && ! ignoreAlphaLevel)
     {

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel.cpp

@@ -2533,23 +2533,36 @@ const Rectangle<int> LookAndFeel::getPropertyComponentContentPosition (PropertyC
 }
 
 //==============================================================================
-void LookAndFeel::drawCallOutBoxBackground (CallOutBox& box, Graphics& g, const Path& path)
+void LookAndFeel::drawCallOutBoxBackground (CallOutBox& box, Graphics& g,
+                                            const Path& path, Image& cachedImage)
 {
-    Image content (Image::ARGB, box.getWidth(), box.getHeight(), true);
-
+    if (cachedImage.isNull())
     {
-        Graphics g2 (content);
+        const int w = box.getWidth();
+        const int h = box.getHeight();
 
-        g2.setColour (Colour::greyLevel (0.23f).withAlpha (0.9f));
-        g2.fillPath (path);
+        Image renderedPath (Image::ARGB, w, h, true);
 
-        g2.setColour (Colours::white.withAlpha (0.8f));
-        g2.strokePath (path, PathStrokeType (2.0f));
+        {
+            Graphics g2 (renderedPath);
+
+            g2.setColour (Colour::greyLevel (0.23f).withAlpha (0.9f));
+            g2.fillPath (path);
+        }
+
+        cachedImage = Image (Image::ARGB, w, h, true);
+        Graphics g2 (cachedImage);
+        DropShadowEffect::drawShadow (g2, renderedPath, 5.0f, 0.4f, 0, 2);
     }
 
-    DropShadowEffect shadow;
-    shadow.setShadowProperties (5.0f, 0.4f, 0, 2);
-    shadow.applyEffect (content, g, 1.0f);
+    g.setColour (Colours::black);
+    g.drawImageAt (cachedImage, 0, 0);
+
+    g.setColour (Colour::greyLevel (0.23f).withAlpha (0.9f));
+    g.fillPath (path);
+
+    g.setColour (Colours::white.withAlpha (0.8f));
+    g.strokePath (path, PathStrokeType (2.0f));
 }
 
 

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel.h

@@ -611,7 +611,7 @@ public:
     virtual const Rectangle<int> getPropertyComponentContentPosition (PropertyComponent& component);
 
     //==============================================================================
-    virtual void drawCallOutBoxBackground (CallOutBox& box, Graphics& g, const Path& path);
+    virtual void drawCallOutBoxBackground (CallOutBox& box, Graphics& g, const Path& path, Image& cachedImage);
 
     //==============================================================================
     virtual void drawLevelMeter (Graphics& g, int width, int height, float level);

modules/juce_gui_basics/native/juce_ios_UIViewComponentPeer.mm

@@ -901,7 +901,7 @@ void UIViewComponentPeer::drawRect (CGRect r)
         CGContextClearRect (cg, CGContextGetClipBoundingBox (cg));
 
     CGContextConcatCTM (cg, CGAffineTransformMake (1, 0, 0, -1, 0, view.bounds.size.height));
-    CoreGraphicsContext g (cg, view.bounds.size.height);
+    CoreGraphicsContext g (cg, view.bounds.size.height, [UIScreen mainScreen].scale);
 
     insideDrawRect = true;
     handlePaint (g);

modules/juce_gui_basics/native/juce_mac_NSViewComponentPeer.mm

@@ -681,7 +681,15 @@ public:
        #if USE_COREGRAPHICS_RENDERING
         if (usingCoreGraphics)
         {
-            CoreGraphicsContext context (cg, (float) [view frame].size.height);
+            float displayScale = 1.0f;
+
+           #if defined (MAC_OS_X_VERSION_10_7) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7)
+            NSScreen* screen = [[view window] screen];
+            if ([screen respondsToSelector: @selector (backingScaleFactor)])
+                displayScale = screen.backingScaleFactor;
+           #endif
+
+            CoreGraphicsContext context (cg, (float) [view frame].size.height, displayScale);
 
             insideDrawRect = true;
             handlePaint (context);

modules/juce_gui_basics/windows/juce_CallOutBox.cpp

@@ -65,15 +65,7 @@ void CallOutBox::setArrowSize (const float newSize)
 
 void CallOutBox::paint (Graphics& g)
 {
-    if (background.isNull())
-    {
-        background = Image (Image::ARGB, getWidth(), getHeight(), true);
-        Graphics g2 (background);
-        getLookAndFeel().drawCallOutBoxBackground (*this, g2, outline);
-    }
-
-    g.setColour (Colours::black);
-    g.drawImageAt (background, 0, 0);
+    getLookAndFeel().drawCallOutBoxBackground (*this, g, outline, background);
 }
 
 void CallOutBox::resized()