Synthesize preserveAspectRatio='none' for non-viewBoxed <img>

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

Index: third_party/WebKit/Source/core/svg/SVGSVGElement.cpp
diff --git a/third_party/WebKit/Source/core/svg/SVGSVGElement.cpp b/third_party/WebKit/Source/core/svg/SVGSVGElement.cpp
index 68d551d29d35d878f93c6b25ebf84467fd95ef1c..80aa89457d97d9a038f7188a390fa88bb6b1b73b 100644
--- a/third_party/WebKit/Source/core/svg/SVGSVGElement.cpp
+++ b/third_party/WebKit/Source/core/svg/SVGSVGElement.cpp
@@ -567,6 +567,13 @@ bool SVGSVGElement::selfHasRelativeLengths() const
         || m_height->currentValue()->isRelative();
 }
 
+bool SVGSVGElement::shouldSynthesizeViewBox() const
+{
+    return layoutObject()
+        && layoutObject()->isSVGRoot()
+        && toLayoutSVGRoot(layoutObject())->isEmbeddedThroughSVGImage();
+}
+
 FloatRect SVGSVGElement::currentViewBoxRect() const

[davve, 2016/09/01 17:46:42]

I bothers me a bit that currentViewBoxRect() may return something (relevant)
even though hasEmptyViewBox() is true. Makes top code in
SVGSVGElement::localCoordinateSpaceTransform look a bit odd to me. Nothing new
to this CL, however.

[fs, 2016/09/01 17:57:24]

Yeah, I noticed this too... Did feel that I should do something about it in this
CL though.

 {
     if (m_useCurrentView) {
@@ -577,14 +584,33 @@ FloatRect SVGSVGElement::currentViewBoxRect() const
     FloatRect useViewBox = viewBox()->currentValue()->value();
     if (!useViewBox.isEmpty())
         return useViewBox;
-    if (!layoutObject() || !layoutObject()->isSVGRoot())
-        return FloatRect();
-    if (!toLayoutSVGRoot(layoutObject())->isEmbeddedThroughSVGImage())
+    if (!shouldSynthesizeViewBox())
         return FloatRect();
 
     // If no viewBox is specified but non-relative width/height values, then we
     // should always synthesize a viewBox if we're embedded through a SVGImage.
-    return FloatRect(FloatPoint(), FloatSize(intrinsicWidth(), intrinsicHeight()));
+    FloatSize synthesizedViewBoxSize(intrinsicWidth(), intrinsicHeight());
+    if (!hasIntrinsicWidth())
+        synthesizedViewBoxSize.setWidth(width()->currentValue()->scaleByPercentage(currentViewportSize().width()));

[davve, 2016/09/01 17:46:42]

So a <svg .. width="50%" height="50%"> would produce the top quarter of the
graphic that would normally be drawn with no width or height, in the same setup?
A bit strange, but oh well I see FF does the exact same thing.

https://software.hixie.ch/utilities/js/live-dom-viewer/?saved=4436 for
illustration.

[fs, 2016/09/01 17:57:24]

Yeah, maybe a bit odd, but I guess it could make some sense in the contexts
where it applies. I also suspect it's quite the odd case that few use...

+    if (!hasIntrinsicHeight())
+        synthesizedViewBoxSize.setHeight(height()->currentValue()->scaleByPercentage(currentViewportSize().height()));
+    return FloatRect(FloatPoint(), synthesizedViewBoxSize);
+}
+
+SVGPreserveAspectRatio* SVGSVGElement::currentPreserveAspectRatio() const
+{
+    if (m_useCurrentView) {
+        DCHECK(m_viewSpec);
+        return m_viewSpec->preserveAspectRatio()->currentValue();
+    }
+    if (!viewBox()->currentValue()->isValid() && shouldSynthesizeViewBox()) {
+        // If no viewBox is specified and we're embedded through SVGImage, then
+        // synthesize a pAR with the value 'none'.
+        SVGPreserveAspectRatio* synthesizedPAR = SVGPreserveAspectRatio::create();
+        synthesizedPAR->setAlign(SVGPreserveAspectRatio::kSvgPreserveaspectratioNone);
+        return synthesizedPAR;
+    }
+    return preserveAspectRatio()->currentValue();
 }
 
 FloatSize SVGSVGElement::currentViewportSize() const
@@ -631,11 +657,11 @@ float SVGSVGElement::intrinsicHeight() const
 
 AffineTransform SVGSVGElement::viewBoxToViewTransform(float viewWidth, float viewHeight) const
 {
+    AffineTransform ctm = SVGFitToViewBox::viewBoxToViewTransform(currentViewBoxRect(), currentPreserveAspectRatio(), viewWidth, viewHeight);
     if (!m_useCurrentView)
-        return SVGFitToViewBox::viewBoxToViewTransform(currentViewBoxRect(), preserveAspectRatio()->currentValue(), viewWidth, viewHeight);
+        return ctm;
     DCHECK(m_viewSpec);
 
-    AffineTransform ctm = SVGFitToViewBox::viewBoxToViewTransform(currentViewBoxRect(), m_viewSpec->preserveAspectRatio()->currentValue(), viewWidth, viewHeight);
     SVGTransformList* transformList = m_viewSpec->transform();
     if (transformList->isEmpty())
         return ctm;