Re-implement SVG transform paint property nodes [spv2]

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"
@@ skipping 20 matching lines @@
     {
         return adoptPtr(new ObjectPaintProperties());
     }
 
     // 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.
+    //     |   +---[ svgLocalToBorderBoxTransform ] Additional transform for children of the root SVG.

[fs, 2016/06/10 08:21:16]

(Maybe mention that this would only ever apply for (outermost) <svg> roots. "for
children of the root" might make people think this node could usefully apply in
other places as well.)

[pdr., 2016/06/10 17:50:43]

SGTM, done.

     //     |              OR                (SVG does not support scrolling.)
     //     |   +---[ scrollTranslation ]    The space created by overflow clip.
     //     +---[ 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* svgLocalToBorderBoxTransform() const { return m_svgLocalToBorderBoxTransform.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 16 matching lines @@
 
     friend class PaintPropertyTreeBuilder;
     // These setters should only be used by PaintPropertyTreeBuilder.
     void setPaintOffsetTranslation(PassRefPtr<TransformPaintPropertyNode> paintOffset) { m_paintOffsetTranslation = paintOffset; }
     void setTransform(PassRefPtr<TransformPaintPropertyNode> transform) { m_transform = transform; }
     void setEffect(PassRefPtr<EffectPaintPropertyNode> effect) { m_effect = effect; }
     void setCssClip(PassRefPtr<ClipPaintPropertyNode> clip) { m_cssClip = clip; }
     void setCssClipFixedPosition(PassRefPtr<ClipPaintPropertyNode> clip) { m_cssClipFixedPosition = clip; }
     void setOverflowClip(PassRefPtr<ClipPaintPropertyNode> clip) { m_overflowClip = clip; }
     void setPerspective(PassRefPtr<TransformPaintPropertyNode> perspective) { m_perspective = perspective; }
-    void setSvgLocalTransform(PassRefPtr<TransformPaintPropertyNode> transform)
+    void setSvgLocalToBorderBoxTransform(PassRefPtr<TransformPaintPropertyNode> transform)
     {
-        DCHECK(!scrollTranslation()) << "SVG elements cannot scroll so there should never be both a scroll translation and an SVG local transform.";
-        m_svgLocalTransform = transform;
+        DCHECK(!scrollTranslation()) << "SVG elements cannot scroll so there should never be both a scroll translation and an SVG local to border box transform.";
+        m_svgLocalToBorderBoxTransform = transform;
     }
     void setScrollTranslation(PassRefPtr<TransformPaintPropertyNode> translation)
     {
-        DCHECK(!svgLocalTransform()) << "SVG elements cannot scroll so there should never be both a scroll translation and an SVG local transform.";
+        DCHECK(!svgLocalToBorderBoxTransform()) << "SVG elements cannot scroll so there should never be both a scroll translation and an SVG local to border box transform.";
         m_scrollTranslation = translation;
     }
     void setScrollbarPaintOffset(PassRefPtr<TransformPaintPropertyNode> paintOffset) { m_scrollbarPaintOffset = paintOffset; }
     void setLocalBorderBoxProperties(PassOwnPtr<LocalBorderBoxProperties> properties) { m_localBorderBoxProperties = std::move(properties); }
 
     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;
+    // TODO(pdr): Only LayoutSVGRoot needs this and it should be moved there.
+    RefPtr<TransformPaintPropertyNode> m_svgLocalToBorderBoxTransform;
     RefPtr<TransformPaintPropertyNode> m_scrollTranslation;
     RefPtr<TransformPaintPropertyNode> m_scrollbarPaintOffset;
 
     OwnPtr<LocalBorderBoxProperties> m_localBorderBoxProperties;
 };
 
 } // namespace blink
 
 #endif // ObjectPaintProperties_h