Make 'transform' a presentation attribute on SVG elements

third_party/WebKit/Source/core/svg/SVGElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann
  * <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 294 matching lines @@
       animatedProperty->animationEnded();
   });
 }
 
 AffineTransform SVGElement::localCoordinateSpaceTransform(CTMScope) const {
   // To be overriden by SVGGraphicsElement (or as special case SVGTextElement
   // and SVGPatternElement)
   return AffineTransform();
 }
 
+bool SVGElement::hasTransform() const {
+  return layoutObject() && layoutObject()->styleRef().hasTransform();
+}
+
+AffineTransform SVGElement::calculateTransform() const {
+  const ComputedStyle* style =
+      layoutObject() ? layoutObject()->style() : nullptr;
+
+  // If CSS property was set, use that, otherwise fallback to attribute (if
+  // set).
+  if (!style || !style->hasTransform())
+    return AffineTransform();
+
+  TransformationMatrix transform;
+  float zoom = style->effectiveZoom();
+
+  // SVGTextElements need special handling for the text positioning code.
+  if (isSVGTextElement(this)) {
+    // Do not take into account SVG's zoom rules, transform-origin, or
+    // percentage values.
+    style->applyTransform(transform, LayoutSize(0, 0),
+                          ComputedStyle::ExcludeTransformOrigin,
+                          ComputedStyle::IncludeMotionPath,
+                          ComputedStyle::IncludeIndependentTransformProperties);
+  } else {
+    // CSS transforms operate with pre-scaled lengths. To make this work with
+    // SVG (which applies the zoom factor globally, at the root level) we
+    //
+    //   * pre-scale the bounding box (to bring it into the same space as the
+    //     other CSS values)
+    //   * invert the zoom factor (to effectively compute the CSS transform
+    //     under a 1.0 zoom)
+    //
+    // Note: objectBoundingBox is an emptyRect for elements like pattern or
+    // clipPath.  See the "Object bounding box units" section of
+    // http://dev.w3.org/csswg/css3-transforms/
+    if (zoom != 1) {
+      FloatRect scaledBBox = layoutObject()->objectBoundingBox();
+      scaledBBox.scale(zoom);
+      transform.scale(1 / zoom);
+      style->applyTransform(
+          transform, scaledBBox, ComputedStyle::IncludeTransformOrigin,
+          ComputedStyle::IncludeMotionPath,
+          ComputedStyle::IncludeIndependentTransformProperties);
+      transform.scale(zoom);
+    } else {
+      style->applyTransform(
+          transform, layoutObject()->objectBoundingBox(),
+          ComputedStyle::IncludeTransformOrigin,
+          ComputedStyle::IncludeMotionPath,

[pdr., 2016/11/22 04:02:48]

Does this include motion path but exclude animate motion? Is that correct?

[fs, 2016/11/22 13:54:07]

Yes, correct. (SVGGraphicsElement::calculateAnimatedLocalTransform applies the
latter.)

+          ComputedStyle::IncludeIndependentTransformProperties);
+    }
+  }
+  // Flatten any 3D transform.
+  return transform.toAffineTransform();
+}
+
 Node::InsertionNotificationRequest SVGElement::insertedInto(
     ContainerNode* rootParent) {
   Element::insertedInto(rootParent);
   updateRelativeLengthsInformation();
   buildPendingResourcesIfNeeded();
   return InsertionDone;
 }
 
 void SVGElement::removedFrom(ContainerNode* rootParent) {
   bool wasInDocument = rootParent->isConnected();
@@ skipping 919 matching lines @@
   visitor->trace(m_className);
   Element::trace(visitor);
 }
 
 const AtomicString& SVGElement::eventParameterName() {
   DEFINE_STATIC_LOCAL(const AtomicString, evtString, ("evt"));
   return evtString;
 }
 
 }  // namespace blink