Fix invalid selection produced when dragging mouse outside the SVG text element

third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.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 10 matching lines @@
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/layout/svg/LayoutSVGRoot.h"
 
 #include "core/frame/LocalFrame.h"
 #include "core/layout/HitTestResult.h"
 #include "core/layout/LayoutAnalyzer.h"
 #include "core/layout/LayoutPart.h"
 #include "core/layout/LayoutView.h"
+#include "core/layout/svg/LayoutSVGText.h"
 #include "core/layout/svg/SVGLayoutSupport.h"
 #include "core/layout/svg/SVGResourcesCache.h"
 #include "core/paint/PaintLayer.h"
 #include "core/paint/SVGRootPainter.h"
 #include "core/svg/SVGElement.h"
 #include "core/svg/SVGSVGElement.h"
 #include "core/svg/graphics/SVGImage.h"
 #include "platform/LengthFunctions.h"
 
 namespace blink {
@@ skipping 233 matching lines @@
     LayoutReplaced::insertedIntoTree();
     SVGResourcesCache::clientWasAddedToTree(this, styleRef());
 }
 
 void LayoutSVGRoot::willBeRemovedFromTree()
 {
     SVGResourcesCache::clientWillBeRemovedFromTree(this);
     LayoutReplaced::willBeRemovedFromTree();
 }
 
+PositionWithAffinity LayoutSVGRoot::positionForPoint(const LayoutPoint& point)
+{
+    FloatPoint absolutePoint = FloatPoint(point);
+    absolutePoint = m_localToBorderBoxTransform.inverse().mapPoint(absolutePoint);
+    LayoutObject* closestDescendant = SVGLayoutSupport::findSelectedLayoutSVGText(this, absolutePoint);
+
+    if (!closestDescendant)
+        return LayoutReplaced::positionForPoint(point);
+
+    LayoutObject* layoutObject = closestDescendant;
+    AffineTransform transform;
+    while (layoutObject) {

[fs, 2016/01/18 12:44:11]

The computation done by this loop does not look correct (the transform of
closestDescendant isn't included.)

+        layoutObject = layoutObject->parent();
+        if (layoutObject->isSVGRoot())
+            break;
+        transform = layoutObject->localToParentTransform() * transform;
+    }
+
+    AffineTransform closestDescendantTransform;
+    if (toLayoutSVGText(closestDescendant)->location().x())

[fs, 2016/01/18 12:44:11]

I don't see why this is needed.

[hyunjunekim2, 2016/01/18 13:32:48]

It needs codes. Because the transform is not applied to location of
LayoutSVGText.
So if no this codes, should disturb selection.

[fs, 2016/01/18 13:56:23]

Ah, this is compensating for the reverse thing in
LayoutSVGInlineText::positionForPoint... You could write this as
AffineTransform::translation(...) or transform.translate(...).

+        closestDescendantTransform.setE(toLayoutSVGText(closestDescendant)->location().x());
+    if (toLayoutSVGText(closestDescendant)->location().y())
+        closestDescendantTransform.setF(toLayoutSVGText(closestDescendant)->location().y());
+
+    transform = transform * closestDescendantTransform;
+
+    absolutePoint = transform.inverse().mapPoint(absolutePoint);
+    if (absolutePoint.x() < 0)

[fs, 2016/01/18 12:44:11]

Suggest to push this down into the callee chain.

+        absolutePoint.setX(0);
+    if (absolutePoint.y() < 0)
+        absolutePoint.setY(0);
+
+    return closestDescendant->positionForPoint(LayoutPoint(absolutePoint.x(), absolutePoint.y()));

[fs, 2016/01/18 12:44:11]

LayoutPoint(absolutePoint) should work just fine.

+}
+
 // LayoutBox methods will expect coordinates w/o any transforms in coordinates
 // relative to our borderBox origin.  This method gives us exactly that.
 void LayoutSVGRoot::buildLocalToBorderBoxTransform()
 {
     SVGSVGElement* svg = toSVGSVGElement(node());
     ASSERT(svg);
     float scale = style()->effectiveZoom();
     FloatPoint translate = svg->currentTranslate();
     LayoutSize borderAndPadding(borderLeft() + paddingLeft(), borderTop() + paddingTop());
     m_localToBorderBoxTransform = svg->viewBoxToViewTransform(contentWidth() / scale, contentHeight() / scale);
@@ skipping 115 matching lines @@
             updateHitTestResult(result, pointInBorderBox);
             if (!result.addNodeToListBasedTestResult(node(), locationInContainer, boundsRect))
                 return true;
         }
     }
 
     return false;
 }
 
 }