Support subpixel values for text-shadow and box-shadow

Source/core/rendering/style/ShadowList.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/rendering/style/ShadowList.h"
 
 #include "platform/geometry/FloatRect.h"
-#include "platform/geometry/LayoutRect.h"
 
 namespace WebCore {
 
-static inline void calculateShadowExtent(const ShadowList* shadowList, int additionalOutlineSize, int& shadowLeft, int& shadowRight, int& shadowTop, int& shadowBottom)
+static inline void calculateShadowExtent(const ShadowList* shadowList, float additionalOutlineSize, float& shadowLeft, float& shadowRight, float& shadowTop, float& shadowBottom)
 {
     ASSERT(shadowList);
     size_t shadowCount = shadowList->shadows().size();
     for (size_t i = 0; i < shadowCount; ++i) {
         const ShadowData& shadow = shadowList->shadows()[i];
         if (shadow.style() == Inset)
             continue;
-        int blurAndSpread = shadow.blur() + shadow.spread() + additionalOutlineSize;
+        float blurAndSpread = shadow.blur() + shadow.spread() + additionalOutlineSize;
         shadowLeft = std::min(shadow.x() - blurAndSpread, shadowLeft);
         shadowRight = std::max(shadow.x() + blurAndSpread, shadowRight);
         shadowTop = std::min(shadow.y() - blurAndSpread, shadowTop);
         shadowBottom = std::max(shadow.y() + blurAndSpread, shadowBottom);
     }
 }
 
-void ShadowList::adjustRectForShadow(LayoutRect& rect, int additionalOutlineSize) const
+void ShadowList::adjustRectForShadow(LayoutRect& rect, LayoutUnit additionalOutlineSize) const

[cbiesinger, 2014/01/15 21:27:40]

Turns out we do need both versions; rendering/svg/RenderSVGText.cpp uses the
FloatRect one and the two other callers use LayoutRects.

However, the one caller that passes a nonzero additionalOutlineSize passes an
integer. I've changed the type to a float.

 {
-    int shadowLeft = 0;
-    int shadowRight = 0;
-    int shadowTop = 0;
-    int shadowBottom = 0;
+    float shadowLeft = 0;
+    float shadowRight = 0;
+    float shadowTop = 0;
+    float shadowBottom = 0;
     calculateShadowExtent(this, additionalOutlineSize, shadowLeft, shadowRight, shadowTop, shadowBottom);
 
     rect.move(shadowLeft, shadowTop);
     rect.setWidth(rect.width() - shadowLeft + shadowRight);

[leviw_travelin_and_unemployed, 2014/01/14 22:28:35]

This seems to just treat the LayoutUnits like floats (implicitly). If that's the
behavior we want, shouldn't we just have this call through to the float version?

[cbiesinger, 2014/01/15 21:27:40]

Changed.

     rect.setHeight(rect.height() - shadowTop + shadowBottom);
 }
 
-void ShadowList::adjustRectForShadow(FloatRect& rect, int additionalOutlineSize) const
+void ShadowList::adjustRectForShadow(FloatRect& rect, float additionalOutlineSize) const
 {
-    int shadowLeft = 0;
-    int shadowRight = 0;
-    int shadowTop = 0;
-    int shadowBottom = 0;
+    float shadowLeft = 0;
+    float shadowRight = 0;
+    float shadowTop = 0;
+    float shadowBottom = 0;
     calculateShadowExtent(this, additionalOutlineSize, shadowLeft, shadowRight, shadowTop, shadowBottom);
 
     rect.move(shadowLeft, shadowTop);
     rect.setWidth(rect.width() - shadowLeft + shadowRight);
     rect.setHeight(rect.height() - shadowTop + shadowBottom);
 }
 
 PassRefPtr<ShadowList> ShadowList::blend(const ShadowList* from, const ShadowList* to, double progress)
 {
     size_t fromLength = from ? from->shadows().size() : 0;
     size_t toLength = to ? to->shadows().size() : 0;
     if (!fromLength && !toLength)
         return 0;
 
     ShadowDataVector shadows;
 
-    DEFINE_STATIC_LOCAL(ShadowData, defaultShadowData, (IntPoint(), 0, 0, Normal, Color::transparent));
-    DEFINE_STATIC_LOCAL(ShadowData, defaultInsetShadowData, (IntPoint(), 0, 0, Inset, Color::transparent));
+    DEFINE_STATIC_LOCAL(ShadowData, defaultShadowData, (FloatPoint(), 0, 0, Normal, Color::transparent));
+    DEFINE_STATIC_LOCAL(ShadowData, defaultInsetShadowData, (FloatPoint(), 0, 0, Inset, Color::transparent));
 
     size_t maxLength = std::max(fromLength, toLength);
     for (size_t i = 0; i < maxLength; ++i) {
         const ShadowData* fromShadow = i < fromLength ? &from->shadows()[i] : 0;
         const ShadowData* toShadow = i < toLength ? &to->shadows()[i] : 0;
         if (!fromShadow)
             fromShadow = toShadow->style() == Inset ? &defaultInsetShadowData : &defaultShadowData;
         else if (!toShadow)
             toShadow = fromShadow->style() == Inset ? &defaultInsetShadowData : &defaultShadowData;
         shadows.append(toShadow->blend(*fromShadow, progress));
     }
 
     return ShadowList::adopt(shadows);
 }
 
 } // namespace WebCore