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

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

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Google, Inc.
  *
  * 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.
@@ skipping 549 matching lines @@
 }
 
 bool SVGSVGElement::selfHasRelativeLengths() const
 {
     return m_x->currentValue()->isRelative()
         || m_y->currentValue()->isRelative()
         || m_width->currentValue()->isRelative()
         || 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) {
         DCHECK(m_viewSpec);
         return m_viewSpec->viewBox()->currentValue()->value();
     }
 
     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
 {
     if (!layoutObject())
         return FloatSize();
 
     if (layoutObject()->isSVGRoot()) {
         LayoutRect contentBoxRect = toLayoutSVGRoot(layoutObject())->contentBoxRect();
         return FloatSize(contentBoxRect.width() / layoutObject()->style()->effectiveZoom(), contentBoxRect.height() / layoutObject()->style()->effectiveZoom());
@@ skipping 26 matching lines @@
 {
     if (height()->currentValue()->typeWithCalcResolved() == CSSPrimitiveValue::UnitType::Percentage)
         return 0;
 
     SVGLengthContext lengthContext(this);
     return height()->currentValue()->value(lengthContext);
 }
 
 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;
 
     AffineTransform transform;
     if (transformList->concatenate(transform))
         ctm *= transform;
 
     return ctm;
 }
@@ skipping 87 matching lines @@
     visitor->trace(m_width);
     visitor->trace(m_height);
     visitor->trace(m_translation);
     visitor->trace(m_timeContainer);
     visitor->trace(m_viewSpec);
     SVGGraphicsElement::trace(visitor);
     SVGFitToViewBox::trace(visitor);
 }
 
 } // namespace blink