Add a transform paint property for local SVG transforms

third_party/WebKit/Source/core/paint/ObjectPaintProperties.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ObjectPaintProperties_h
 #define ObjectPaintProperties_h
 
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/EffectPaintPropertyNode.h"
 #include "platform/graphics/paint/PaintChunkProperties.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 // This class stores property tree related information associated with a LayoutObject.
 // Currently there are two groups of information:
 // 1. The set of property nodes created locally by this LayoutObject.
 // 2. [Optional] A suite of property nodes (PaintChunkProperties) and paint offset
 //    that can be used to paint the border box of this LayoutObject.
 class ObjectPaintProperties {
     WTF_MAKE_NONCOPYABLE(ObjectPaintProperties);
     USING_FAST_MALLOC(ObjectPaintProperties);
 public:
     struct LocalBorderBoxProperties;
 
+    // TODO(pdr): This should be refactored to not pass 11 arguments because it
+    // is hard to follow here and at the callsites.
     static PassOwnPtr<ObjectPaintProperties> create(
         PassRefPtr<TransformPaintPropertyNode> paintOffsetTranslation,
         PassRefPtr<TransformPaintPropertyNode> transform,
         PassRefPtr<EffectPaintPropertyNode> effect,
         PassRefPtr<ClipPaintPropertyNode> cssClip,
         PassRefPtr<ClipPaintPropertyNode> cssClipFixedPosition,
         PassRefPtr<ClipPaintPropertyNode> overflowClip,
         PassRefPtr<TransformPaintPropertyNode> perspective,
+        PassRefPtr<TransformPaintPropertyNode> svgLocalTransform,
         PassRefPtr<TransformPaintPropertyNode> scrollTranslation,
         PassRefPtr<TransformPaintPropertyNode> scrollbarPaintOffset,
         PassOwnPtr<LocalBorderBoxProperties> localBorderBoxProperties)
     {
-        return adoptPtr(new ObjectPaintProperties(paintOffsetTranslation, transform, effect, cssClip, cssClipFixedPosition, overflowClip, perspective, scrollTranslation, scrollbarPaintOffset, localBorderBoxProperties));
+        return adoptPtr(new ObjectPaintProperties(paintOffsetTranslation,
+            transform, effect, cssClip, cssClipFixedPosition, overflowClip,
+            perspective, svgLocalTransform, scrollTranslation,
+            scrollbarPaintOffset, localBorderBoxProperties));
     }
 
     // The hierarchy of transform subtree created by a LayoutObject.
     // [ paintOffsetTranslation ]           Normally paint offset is accumulated without creating a node
     // |                                    until we see, for example, transform or position:fixed.
     // +---[ transform ]                    The space created by CSS transform.
     //     |                                This is the local border box space, see: LocalBorderBoxProperties below.
     //     +---[ perspective ]              The space created by CSS perspective.
+    //     |   +---[ svgLocalTransform ]    The transform for an SVG element.
     //     |   +---[ scrollTranslation ]    The space created by overflow clip.

[jbroman, 2016/04/07 14:37:11]

Can an element have both an SVG local transform and a scroll translation? (If
so, can you confirm that this is the right hierarchy?)

[jbroman, 2016/04/07 18:47:38]

Would you mind clarifying this? The code in question updates the context when it
creates both of them, so if both could be created, then they would be parent and
child, not siblings.

If you don't want to draw it as parent-child, perhaps something like:

   +--[ svgLocalTransform ]
         OR
   +--[ scrollTranslation ]

With a DCHECK after creating both that they don't exist simultaneously, i.e.

DCHECK(!newTransformNodeForSvgLocalTransform ||
!newTransformNodeForScrollTranslation)
    << "SVG elements cannot have scroll translation";

     //     +---[ scrollbarPaintOffset ]     TODO(trchen): Remove this once we bake the paint offset into frameRect.
     //                                      This is equivalent to the local border box space above,
     //                                      with pixel snapped paint offset baked in. It is really redundant,
     //                                      but it is a pain to teach scrollbars to paint with an offset.
     TransformPaintPropertyNode* paintOffsetTranslation() const { return m_paintOffsetTranslation.get(); }
     TransformPaintPropertyNode* transform() const { return m_transform.get(); }
     TransformPaintPropertyNode* perspective() const { return m_perspective.get(); }
+    TransformPaintPropertyNode* svgLocalTransform() const { return m_svgLocalTransform.get(); }
     TransformPaintPropertyNode* scrollTranslation() const { return m_scrollTranslation.get(); }
     TransformPaintPropertyNode* scrollbarPaintOffset() const { return m_scrollbarPaintOffset.get(); }
 
     EffectPaintPropertyNode* effect() const { return m_effect.get(); }
 
     ClipPaintPropertyNode* cssClip() const { return m_cssClip.get(); }
     ClipPaintPropertyNode* cssClipFixedPosition() const { return m_cssClipFixedPosition.get(); }
     ClipPaintPropertyNode* overflowClip() const { return m_overflowClip.get(); }
 
     // This is a complete set of property nodes that should be used as a starting point to paint
@@ skipping 13 matching lines @@
 
 private:
     ObjectPaintProperties(
         PassRefPtr<TransformPaintPropertyNode> paintOffsetTranslation,
         PassRefPtr<TransformPaintPropertyNode> transform,
         PassRefPtr<EffectPaintPropertyNode> effect,
         PassRefPtr<ClipPaintPropertyNode> cssClip,
         PassRefPtr<ClipPaintPropertyNode> cssClipFixedPosition,
         PassRefPtr<ClipPaintPropertyNode> overflowClip,
         PassRefPtr<TransformPaintPropertyNode> perspective,
+        PassRefPtr<TransformPaintPropertyNode> svgLocalTransform,
         PassRefPtr<TransformPaintPropertyNode> scrollTranslation,
         PassRefPtr<TransformPaintPropertyNode> scrollbarPaintOffset,
         PassOwnPtr<LocalBorderBoxProperties> localBorderBoxProperties)
         : m_paintOffsetTranslation(paintOffsetTranslation)
         , m_transform(transform)
         , m_effect(effect)
         , m_cssClip(cssClip)
         , m_cssClipFixedPosition(cssClipFixedPosition)
         , m_overflowClip(overflowClip)
         , m_perspective(perspective)
+        , m_svgLocalTransform(svgLocalTransform)
         , m_scrollTranslation(scrollTranslation)
         , m_scrollbarPaintOffset(scrollbarPaintOffset)
         , m_localBorderBoxProperties(localBorderBoxProperties) { }
 
     RefPtr<TransformPaintPropertyNode> m_paintOffsetTranslation;
     RefPtr<TransformPaintPropertyNode> m_transform;
     RefPtr<EffectPaintPropertyNode> m_effect;
     RefPtr<ClipPaintPropertyNode> m_cssClip;
     RefPtr<ClipPaintPropertyNode> m_cssClipFixedPosition;
     RefPtr<ClipPaintPropertyNode> m_overflowClip;
     RefPtr<TransformPaintPropertyNode> m_perspective;
+    RefPtr<TransformPaintPropertyNode> m_svgLocalTransform;
     RefPtr<TransformPaintPropertyNode> m_scrollTranslation;
     RefPtr<TransformPaintPropertyNode> m_scrollbarPaintOffset;
 
     OwnPtr<LocalBorderBoxProperties> m_localBorderBoxProperties;
 };
 
 } // namespace blink
 
 #endif // ObjectPaintProperties_h