[SVG2] Make transform, gradientTransform and patternTransform presentation attributes.

Source/core/svg/GradientAttributes.h

 /*
  * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 34 matching lines @@
         m_spreadMethod = value;
         m_spreadMethodSet = true;
     }
 
     void setGradientUnits(SVGUnitTypes::SVGUnitType unitType)
     {
         m_gradientUnits = unitType;
         m_gradientUnitsSet = true;
     }
 
+    void setGradientTransformFromStyle(SVGGradientElement* element)
+    {
+        AffineTransform transform;
+        RenderStyle* style = element->renderer() ? element->renderer()->style() : 0;
+
+        // If CSS property was set, use that, otherwise fallback to attribute (if set).
+        if (style && style->hasTransform()) {
+            TransformationMatrix matrix;
+            float zoom = style->effectiveZoom();
+
+            // CSS transforms operate with pre-scaled lengths. To make this work with SVG

[pdr., 2014/08/01 22:43:10]

This logic is all duplicated from SVGGraphicsElement::animatedLocalTransform.
Can you extract the svg/css transform logic out so it can be shared with
patterns, gradients, and SVGGraphicsElement too?

[Erik Dahlström (inactive), 2014/08/04 13:57:57]

Yes, who likes duplicated code, right? :) I'll see what I can do.

+            // (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 = element->renderer()->objectBoundingBox();
+                scaledBBox.scale(zoom);
+                transform.scale(1 / zoom);
+                style->applyTransform(matrix, scaledBBox);
+                matrix.scale(zoom);
+            } else {
+                style->applyTransform(matrix, element->renderer()->objectBoundingBox());
+            }
+
+            // Flatten any 3D transform.
+            transform = matrix.toAffineTransform();
+        } else if (element->gradientTransform()->isSpecified()) {
+            element->gradientTransform()->currentValue()->concatenate(transform);
+        }
+
+        if (!transform.isIdentity())

[pdr., 2014/08/01 22:43:10]

Is this check needed?

[Erik Dahlström (inactive), 2014/08/04 13:57:57]

Technically no, since it won't make any visible difference. Was added to mostly
mimic the old code (which checked for the existence of the attribute). The
setGradientTransform method toggles a flag that makes the processing consider
the transform later on.

I guess this could just as well be if(style->hasTransform() ||
element->gradientTransform()->isSpecified()) instead.

+            setGradientTransform(transform);
+    }
+
     void setGradientTransform(const AffineTransform& value)
     {
         m_gradientTransform = value;
         m_gradientTransformSet = true;
     }
 
     void setStops(const Vector<Gradient::ColorStop>& value)
     {
         m_stops = value;
         m_stopsSet = true;
@@ skipping 23 matching lines @@
     AffineTransform a;
     Vector<Gradient::ColorStop> b;
     unsigned c : 8;
 };
 
 COMPILE_ASSERT(sizeof(GradientAttributes) == sizeof(SameSizeAsGradientAttributes), GradientAttributes_size_guard);
 
 } // namespace blink
 
 #endif