Fixup a bug about SVG text selection.

Source/core/layout/svg/LayoutSVGInlineText.cpp

 /*
  * Copyright (C) 2006 Oliver Hunt <ojh16@student.canterbury.ac.nz>
  * Copyright (C) 2006 Apple Computer Inc.
  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2008 Rob Buis <buis@kde.org>
  * Copyright (C) Research In Motion Limited 2010. 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 41 matching lines @@
     // copy of the original character data content. First, it will remove all newline
     // characters. Then it will convert all tab characters into space characters.
     // Then, it will strip off all leading and trailing space characters.
     // Then, all contiguous space characters will be consolidated.
     RefPtr<StringImpl> newString = string->replace('\n', StringImpl::empty());
     newString = newString->replace('\r', StringImpl::empty());
     newString = newString->replace('\t', ' ');
     return newString.release();
 }
 
+static float squaredDistanceToClosestPoint(const FloatRect& rect, const FloatPoint& point)
+{
+    FloatPoint closestPoint;
+    closestPoint.setX(std::max(std::min(point.x(), rect.maxX()), rect.x()));
+    closestPoint.setY(std::max(std::min(point.y(), rect.maxY()), rect.y()));
+    return (point - closestPoint).diagonalLengthSquared();
+}
+
 LayoutSVGInlineText::LayoutSVGInlineText(Node* n, PassRefPtr<StringImpl> string)
     : LayoutText(n, applySVGWhitespaceRules(string, false))
     , m_scalingFactor(1)
     , m_layoutAttributes(this)
 {
 }
 
 void LayoutSVGInlineText::setTextInternal(PassRefPtr<StringImpl> text)
 {
     LayoutText::setTextInternal(text);
@@ skipping 76 matching lines @@
         return false;
 
     return it->value.x != SVGTextLayoutAttributes::emptyValue() || it->value.y != SVGTextLayoutAttributes::emptyValue();
 }
 
 PositionWithAffinity LayoutSVGInlineText::positionForPoint(const LayoutPoint& point)
 {
     if (!firstTextBox() || !textLength())
         return createPositionWithAffinity(0, DOWNSTREAM);
 
-    float baseline = m_scaledFont.fontMetrics().floatAscent();
+    ASSERT(m_scalingFactor);
+    float baseline = m_scaledFont.fontMetrics().floatAscent() / m_scalingFactor;
 
     LayoutBlock* containingBlock = this->containingBlock();
     ASSERT(containingBlock);
 
     // Map local point to absolute point, as the character origins stored in the text fragments use absolute coordinates.
     FloatPoint absolutePoint(point);
     absolutePoint.moveBy(containingBlock->location());
 
     float closestDistance = std::numeric_limits<float>::max();
     float closestDistancePosition = 0;
     const SVGTextFragment* closestDistanceFragment = 0;
     SVGInlineTextBox* closestDistanceBox = 0;
 
     AffineTransform fragmentTransform;
     for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
         if (!box->isSVGInlineTextBox())
             continue;
 
         SVGInlineTextBox* textBox = toSVGInlineTextBox(box);
         Vector<SVGTextFragment>& fragments = textBox->textFragments();
 
         unsigned textFragmentsSize = fragments.size();
         for (unsigned i = 0; i < textFragmentsSize; ++i) {
             const SVGTextFragment& fragment = fragments.at(i);
             FloatRect fragmentRect(fragment.x, fragment.y - baseline, fragment.width, fragment.height);
             fragment.buildFragmentTransform(fragmentTransform);
-            fragmentRect = fragmentTransform.mapRect(fragmentRect);
+            if (!fragmentTransform.isIdentity())
+                fragmentRect = fragmentTransform.mapRect(fragmentRect);
 
-            float distance = powf(fragmentRect.x() - absolutePoint.x(), 2) +
-                powf(fragmentRect.y() + fragmentRect.height() / 2 - absolutePoint.y(), 2);
+            float distance = 0;
+            if (!fragmentRect.contains(absolutePoint))
+                distance = squaredDistanceToClosestPoint(fragmentRect, absolutePoint);
 
-            if (distance < closestDistance) {
+            if (distance <= closestDistance) {
                 closestDistance = distance;
                 closestDistanceBox = textBox;
                 closestDistanceFragment = &fragment;
                 closestDistancePosition = fragmentRect.x();
             }
         }
     }
 
     if (!closestDistanceFragment)
         return createPositionWithAffinity(0, DOWNSTREAM);
@@ skipping 43 matching lines @@
 
 PassRefPtr<StringImpl> LayoutSVGInlineText::originalText() const
 {
     RefPtr<StringImpl> result = LayoutText::originalText();
     if (!result)
         return nullptr;
     return applySVGWhitespaceRules(result, style() && style()->whiteSpace() == PRE);
 }
 
 }