Factor out glyph position computations in SVGTextQuery

Source/core/layout/svg/SVGTextQuery.cpp

 /*
  * Copyright (C) Research In Motion Limited 2010-2012. 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 261 matching lines @@
 struct StartPositionOfCharacterData : SVGTextQuery::Data {
     StartPositionOfCharacterData(unsigned queryPosition)
         : position(queryPosition)
     {
     }
 
     unsigned position;
     FloatPoint startPosition;
 };
 
+static FloatPoint calculateGlyphPositionWithoutTransform(const SVGTextQuery::Data* queryData, const SVGTextFragment& fragment, int offsetInFragment)
+{
+    float glyphOffsetInDirection = 0;
+    if (offsetInFragment) {
+        SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textLayoutObject, fragment.characterOffset, offsetInFragment, queryData->textLayoutObject->styleRef().direction());
+        if (queryData->isVerticalText)
+            glyphOffsetInDirection = metrics.height();
+        else
+            glyphOffsetInDirection = metrics.width();
+    }
+
+    FloatPoint glyphPosition(fragment.x, fragment.y);
+    if (queryData->isVerticalText)
+        glyphPosition.move(0, glyphOffsetInDirection);
+    else
+        glyphPosition.move(glyphOffsetInDirection, 0);
+
+    return glyphPosition;
+}
+
+static FloatPoint calculateGlyphPosition(const SVGTextQuery::Data* queryData, const SVGTextFragment& fragment, int offsetInFragment)
+{
+    FloatPoint glyphPosition = calculateGlyphPositionWithoutTransform(queryData, fragment, offsetInFragment);
+    AffineTransform fragmentTransform;
+    fragment.buildFragmentTransform(fragmentTransform, SVGTextFragment::TransformIgnoringTextLength);
+    if (!fragmentTransform.isIdentity())
+        glyphPosition = fragmentTransform.mapPoint(glyphPosition);
+
+    return glyphPosition;
+}
+
 bool SVGTextQuery::startPositionOfCharacterCallback(Data* queryData, const SVGTextFragment& fragment) const
 {
     StartPositionOfCharacterData* data = static_cast<StartPositionOfCharacterData*>(queryData);
 
     int startPosition = data->position;
     int endPosition = startPosition + 1;
     if (!mapStartEndPositionsIntoFragmentCoordinates(queryData, fragment, startPosition, endPosition))
         return false;
 
-    data->startPosition = FloatPoint(fragment.x, fragment.y);
-
-    if (startPosition) {
-        SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textLayoutObject, fragment.characterOffset, startPosition, queryData->textLayoutObject->styleRef().direction());
-        if (queryData->isVerticalText)
-            data->startPosition.move(0, metrics.height());
-        else
-            data->startPosition.move(metrics.width(), 0);
-    }
-
-    AffineTransform fragmentTransform;
-    fragment.buildFragmentTransform(fragmentTransform, SVGTextFragment::TransformIgnoringTextLength);
-    if (fragmentTransform.isIdentity())
-        return true;
-
-    data->startPosition = fragmentTransform.mapPoint(data->startPosition);
+    data->startPosition = calculateGlyphPosition(queryData, fragment, startPosition);
     return true;
 }
 
 FloatPoint SVGTextQuery::startPositionOfCharacter(unsigned position) const
 {
     StartPositionOfCharacterData data(position);
     executeQuery(&data, &SVGTextQuery::startPositionOfCharacterCallback);
     return data.startPosition;
 }
 
@@ skipping 10 matching lines @@
 
 bool SVGTextQuery::endPositionOfCharacterCallback(Data* queryData, const SVGTextFragment& fragment) const
 {
     EndPositionOfCharacterData* data = static_cast<EndPositionOfCharacterData*>(queryData);
 
     int startPosition = data->position;
     int endPosition = startPosition + 1;
     if (!mapStartEndPositionsIntoFragmentCoordinates(queryData, fragment, startPosition, endPosition))
         return false;
 
-    data->endPosition = FloatPoint(fragment.x, fragment.y);
-
-    SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textLayoutObject, fragment.characterOffset, startPosition + 1, queryData->textLayoutObject->styleRef().direction());
-    if (queryData->isVerticalText)
-        data->endPosition.move(0, metrics.height());
-    else
-        data->endPosition.move(metrics.width(), 0);
-
-    AffineTransform fragmentTransform;
-    fragment.buildFragmentTransform(fragmentTransform, SVGTextFragment::TransformIgnoringTextLength);
-    if (fragmentTransform.isIdentity())
-        return true;
-
-    data->endPosition = fragmentTransform.mapPoint(data->endPosition);
+    // TODO(fs): mapStartEndPositionsIntoFragmentCoordinates(...) above applies
+    // some heuristics for ligatures, so why not just use endPosition here?
+    // (rather than startPosition+1)
+    data->endPosition = calculateGlyphPosition(queryData, fragment, startPosition + 1);
     return true;
 }
 
 FloatPoint SVGTextQuery::endPositionOfCharacter(unsigned position) const
 {
     EndPositionOfCharacterData data(position);
     executeQuery(&data, &SVGTextQuery::endPositionOfCharacterCallback);
     return data.endPosition;
 }
 
@@ skipping 46 matching lines @@
 
     unsigned position;
     FloatRect extent;
 };
 
 static inline void calculateGlyphBoundaries(SVGTextQuery::Data* queryData, const SVGTextFragment& fragment, int startPosition, FloatRect& extent)
 {
     float scalingFactor = queryData->textLayoutObject->scalingFactor();
     ASSERT(scalingFactor);
 
-    extent.setLocation(FloatPoint(fragment.x, fragment.y - queryData->textLayoutObject->scaledFont().fontMetrics().floatAscent() / scalingFactor));
-
-    if (startPosition) {
-        SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textLayoutObject, fragment.characterOffset, startPosition, queryData->textLayoutObject->styleRef().direction());
-        if (queryData->isVerticalText)
-            extent.move(0, metrics.height());
-        else
-            extent.move(metrics.width(), 0);
-    }
+    FloatPoint glyphPosition = calculateGlyphPositionWithoutTransform(queryData, fragment, startPosition);
+    glyphPosition.move(0, -queryData->textLayoutObject->scaledFont().fontMetrics().floatAscent() / scalingFactor);
+    extent.setLocation(glyphPosition);
 
     SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textLayoutObject, fragment.characterOffset + startPosition, 1, queryData->textLayoutObject->styleRef().direction());
     extent.setSize(FloatSize(metrics.width(), metrics.height()));
 
     AffineTransform fragmentTransform;
     fragment.buildFragmentTransform(fragmentTransform, SVGTextFragment::TransformIgnoringTextLength);
 
     extent = fragmentTransform.mapRect(extent);
 }
 
@@ skipping 72 matching lines @@
 int SVGTextQuery::characterNumberAtPosition(const FloatPoint& position) const
 {
     CharacterNumberAtPositionData data(position);
     if (!executeQuery(&data, &SVGTextQuery::characterNumberAtPositionCallback))
         return -1;
 
     return data.processedCharacters;
 }
 
 }