Flexbox: Allow intrinsic aspect ratios to inform main-size calculation

Source/core/rendering/RenderFlexibleBox.cpp

 /*
  * Copyright (C) 2011 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 590 matching lines @@
 static inline bool preferredMainAxisExtentDependsOnLayout(const Length& flexBasis, bool hasInfiniteLineLength)
 {
     return flexBasis.isAuto() || (flexBasis.isFixed() && !flexBasis.value() && hasInfiniteLineLength);
 }
 
 bool RenderFlexibleBox::childPreferredMainAxisContentExtentRequiresLayout(RenderBox* child, bool hasInfiniteLineLength) const
 {
     return preferredMainAxisExtentDependsOnLayout(flexBasisForChild(child), hasInfiniteLineLength) && hasOrthogonalFlow(child);
 }
 
+bool RenderFlexibleBox::childHasFiniteCrossSize(RenderBox* child) const
+{
+    if (child->style()->logicalHeight().isFixed())
+        return true;
+
+    if (!style()->logicalHeight().isFixed())
+        return false;
+
+    if (child->style()->logicalHeight().isPercent())
+        return true;
+
+    if (!isMultiline() && needToStretchChildLogicalHeight(child))
+        return true;
+
+    return false;
+}
+
+void RenderFlexibleBox::computeAspectRatioOfChild(RenderBox* child, double& aspectRatio, bool& hasAspectRatio)

[tony, 2014/06/26 16:31:28]

The bool seems unnecessary.  Set the initial value of apsectRatio to -1 to mean
no aspect ratio.

[harpreet.sk, 2014/06/30 09:26:07]

Done.

+{
+    if (child->style()->hasAspectRatio()) {
+        hasAspectRatio = true;
+        aspectRatio = child->style()->aspectRatio();
+    } else if (child->isRenderImage() && child->intrinsicLogicalHeight()) {

[tony, 2014/06/26 16:31:28]

Is checking for a RenderImage really the right thing? For example, <video>s also
have aspect ratios.

[harpreet.sk, 2014/06/30 09:26:07]

Sorry only checking for RenderImage is not the right thing. Aspect ratio can be
for image, video or canvas. Added new check for the same.

+        hasAspectRatio = true;
+        aspectRatio = child->intrinsicLogicalWidth().rawValue() / child->intrinsicLogicalHeight().rawValue();
+    }
+}
+
 LayoutUnit RenderFlexibleBox::preferredMainAxisContentExtentForChild(RenderBox* child, bool hasInfiniteLineLength, bool relayoutChildren)
 {
     child->clearOverrideSize();
 
     Length flexBasis = flexBasisForChild(child);
+    double aspectRatio = 1.0f;
+    bool hasAspectRatio = false;
+    computeAspectRatioOfChild(child, aspectRatio, hasAspectRatio);
+
+    if (hasAspectRatio && flexBasis.isAuto() && childHasFiniteCrossSize(child)) {
+        if (!isMultiline() && needToStretchChildLogicalHeight(child))
+            return aspectRatio * style()->logicalHeight().value();
+        return aspectRatio * crossAxisIntrinsicExtentForChild(child);
+    }
+
     if (preferredMainAxisExtentDependsOnLayout(flexBasis, hasInfiniteLineLength)) {
         LayoutUnit mainAxisExtent;
         if (hasOrthogonalFlow(child)) {
             if (child->needsLayout() || relayoutChildren) {
                 m_intrinsicSizeAlongMainAxis.remove(child);
                 child->forceChildLayout();
                 m_intrinsicSizeAlongMainAxis.set(child, child->logicalHeight());
             }
             ASSERT(m_intrinsicSizeAlongMainAxis.contains(child));
             mainAxisExtent = m_intrinsicSizeAlongMainAxis.get(child);
@@ skipping 770 matching lines @@
             ASSERT(child);
             LayoutUnit lineCrossAxisExtent = lineContexts[lineNumber].crossAxisExtent;
             LayoutUnit originalOffset = lineContexts[lineNumber].crossAxisOffset - crossAxisStartEdge;
             LayoutUnit newOffset = contentExtent - originalOffset - lineCrossAxisExtent;
             adjustAlignmentForChild(child, newOffset - originalOffset);
         }
     }
 }
 
 }