Merge image sizing algorithms

third_party/WebKit/Source/core/svg/graphics/SVGImage.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 137 matching lines @@
 
     // If a container size is available it has precedence.
     IntSize containerSize = layoutObject->containerSize();
     if (!containerSize.isEmpty())
         return containerSize;
 
     // Assure that a container size is always given for a non-identity zoom level.
     ASSERT(layoutObject->style()->effectiveZoom() == 1);
 
     // No set container size; use concrete object size.
-    return m_concreteObjectSize;
+    return m_intrinsicSize;
 }
 
 static float resolveWidthForRatio(float height, const FloatSize& intrinsicRatio)
 {
     return height * intrinsicRatio.width() / intrinsicRatio.height();
 }
 
 static float resolveHeightForRatio(float width, const FloatSize& intrinsicRatio)
 {
     return width * intrinsicRatio.height() / intrinsicRatio.width();
@@ skipping 32 matching lines @@
     }
 
     if (intrinsicSizingInfo.hasHeight) {
         if (intrinsicSizingInfo.aspectRatio.isEmpty())
             return FloatSize(defaultObjectSize.width(), intrinsicSizingInfo.size.height());
 
         return FloatSize(resolveWidthForRatio(intrinsicSizingInfo.size.height(), intrinsicSizingInfo.aspectRatio), intrinsicSizingInfo.size.height());
     }
 
     if (!intrinsicSizingInfo.aspectRatio.isEmpty()) {
-        // TODO(davve): According to the specification, the concrete object size should resolve as a
-        // contain constraint against the default object size at this stage. Until the
-        // defaultObjectSize is context sensitive, right now it's hard-coded to 300x150, we have to
-        // preserve legacy behavior by returning the aspectRatio as the concrete object size.
-        return intrinsicSizingInfo.aspectRatio;
+        // "A contain constraint is resolved by setting the concrete object size to the largest
+        //  rectangle that has the object's intrinsic aspect ratio and additionally has neither
+        //  width nor height larger than the constraint rectangle's width and height, respectively."
+        float solutionWidth = resolveWidthForRatio(defaultObjectSize.height(), intrinsicSizingInfo.aspectRatio);
+        float solutionHeight = resolveHeightForRatio(defaultObjectSize.width(), intrinsicSizingInfo.aspectRatio);
+        if (solutionWidth <= defaultObjectSize.width()) {
+            if (solutionHeight <= defaultObjectSize.height()) {
+                float areaOne = solutionWidth * defaultObjectSize.height();
+                float areaTwo = defaultObjectSize.width() * solutionHeight;
+                if (areaOne < areaTwo)
+                    return FloatSize(defaultObjectSize.width(), solutionHeight);
+                return FloatSize(solutionWidth, defaultObjectSize.height());
+            }
+
+            return FloatSize(solutionWidth, defaultObjectSize.height());
+        }
+
+        ASSERT(solutionHeight <= defaultObjectSize.height());
+        return FloatSize(defaultObjectSize.width(), solutionHeight);
     }
 
     return defaultObjectSize;
 }
 
 void SVGImage::drawForContainer(SkCanvas* canvas, const SkPaint& paint, const FloatSize containerSize, float zoom, const FloatRect& dstRect,
     const FloatRect& srcRect, const KURL& url)
 {
     if (!m_page)
         return;
@@ skipping 302 matching lines @@
         frame->view()->setCanHaveScrollbars(false); // SVG Images will always synthesize a viewBox, if it's not available, and thus never see scrollbars.
         frame->view()->setTransparent(true); // SVG Images are transparent.
 
         m_page = page.release();
 
         TRACE_EVENT0("blink", "SVGImage::dataChanged::load");
         loader.load(FrameLoadRequest(0, blankURL(), SubstituteData(data(), AtomicString("image/svg+xml", AtomicString::ConstructFromLiteral),
             AtomicString("UTF-8", AtomicString::ConstructFromLiteral), KURL(), ForceSynchronousLoad)));
 
         // Set the concrete object size before a container size is available.
-        m_concreteObjectSize = roundedIntSize(calculateConcreteObjectSize(FloatSize(300, 150)));
+        m_intrinsicSize = roundedIntSize(calculateConcreteObjectSize(FloatSize(300, 150)));
     }
 
     return m_page;
 }
 
 String SVGImage::filenameExtension() const
 {
     return "svg";
 }
 
 } // namespace blink