SVG does not respect overflow:visible.

Source/core/rendering/svg/RenderSVGRoot.cpp

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007, 2008, 2009 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Google, Inc.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * 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
@@ skipping 210 matching lines @@
         m_needsBoundariesOrTransformUpdate = false;
     }
 
     updateLayerTransform();
 
     repainter.repaintAfterLayout();
 
     clearNeedsLayout();
 }
 
+bool RenderSVGRoot::applyViewportClip() const

[esprehn, 2014/04/05 20:19:22]

this should be named with an "is" or "should" prefix. "apply" sounds like a verb
but this thing is just a getter.

+{
+    // the outermost svg is clipped if auto, and svg document roots are always clipped
+    return style()->overflowX() == OHIDDEN || style()->overflowX() == OAUTO || this->isRoot();
+}
+
 void RenderSVGRoot::paintReplaced(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     // An empty viewport disables rendering.
     if (pixelSnappedBorderBoxRect().isEmpty())
         return;
 
     // Don't paint, if the context explicitly disabled it.
     if (paintInfo.context->paintingDisabled())
         return;
 
     // An empty viewBox also disables rendering.
     // (http://www.w3.org/TR/SVG/coords.html#ViewBoxAttribute)
     SVGSVGElement* svg = toSVGSVGElement(node());
     ASSERT(svg);
     if (svg->hasEmptyViewBox())
         return;
 
     // Don't paint if we don't have kids, except if we have filters we should paint those.
     if (!firstChild()) {
         SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(this);
         if (!resources || !resources->filter())
             return;
     }
 
     // Make a copy of the PaintInfo because applyTransform will modify the damage rect.
     PaintInfo childPaintInfo(paintInfo);
     childPaintInfo.context->save();
 
-    // Apply initial viewport clip - not affected by overflow handling
-    childPaintInfo.context->clip(pixelSnappedIntRect(overflowClipRect(paintOffset)));
+    // Apply initial viewport clip
+    if (applyViewportClip())
+        childPaintInfo.context->clip(pixelSnappedIntRect(overflowClipRect(paintOffset)));
 
     // Convert from container offsets (html renderers) to a relative transform (svg renderers).
     // Transform from our paint container's coordinate system to our local coords.
     IntPoint adjustedPaintOffset = roundedIntPoint(paintOffset);
     childPaintInfo.applyTransform(AffineTransform::translation(adjustedPaintOffset.x(), adjustedPaintOffset.y()) * localToBorderBoxTransform());
 
     // SVGRenderingContext must be destroyed before we restore the childPaintInfo.context, because a filter may have
     // changed the context and it is only reverted when the SVGRenderingContext destructor finishes applying the filter.
     {
         SVGRenderingContext renderingContext;
@@ skipping 86 matching lines @@
 {
     return SVGRenderSupport::clippedOverflowRectForRepaint(this, repaintContainer);
 }
 
 void RenderSVGRoot::computeFloatRectForRepaint(const RenderLayerModelObject* repaintContainer, FloatRect& repaintRect, bool fixed) const
 {
     // Apply our local transforms (except for x/y translation), then our shadow,
     // and then call RenderBox's method to handle all the normal CSS Box model bits
     repaintRect = m_localToBorderBoxTransform.mapRect(repaintRect);
 
-    // Apply initial viewport clip - not affected by overflow settings
-    repaintRect.intersect(pixelSnappedBorderBoxRect());
+    // Apply initial viewport clip
+    if (applyViewportClip())
+        repaintRect.intersect(pixelSnappedBorderBoxRect());
 
     LayoutRect rect = enclosingIntRect(repaintRect);
     RenderReplaced::computeRectForRepaint(repaintContainer, rect, fixed);
     repaintRect = rect;
 }
 
 // This method expects local CSS box coordinates.
 // Callers with local SVG viewport coordinates should first apply the localToBorderBoxTransform
 // to convert from SVG viewport coordinates to local CSS box coordinates.
 void RenderSVGRoot::mapLocalToContainer(const RenderLayerModelObject* repaintContainer, TransformState& transformState, MapCoordinatesFlags mode, bool* wasFixed) const
@@ skipping 62 matching lines @@
 
 bool RenderSVGRoot::hasRelativeLogicalHeight() const
 {
     SVGSVGElement* svg = toSVGSVGElement(node());
     ASSERT(svg);
 
     return svg->intrinsicHeight(SVGSVGElement::IgnoreCSSProperties).isPercent();
 }
 
 }