1 files changed, 562 insertions, 0 deletions
diff --git a/Source/WebCore/rendering/svg/SVGTextQuery.cpp b/Source/WebCore/rendering/svg/SVGTextQuery.cpp
new file mode 100644
index 0000000..fcc7924
--- /dev/null
+++ b/Source/WebCore/rendering/svg/SVGTextQuery.cpp
@@ -0,0 +1,562 @@
+/*
+    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
+    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
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+
+#include "config.h"
+#include "SVGTextQuery.h"
+
+#if ENABLE(SVG)
+#include "FloatConversion.h"
+#include "InlineFlowBox.h"
+#include "RenderBlock.h"
+#include "RenderInline.h"
+#include "RenderSVGInlineText.h"
+#include "SVGInlineTextBox.h"
+#include "SVGTextMetrics.h"
+#include "VisiblePosition.h"
+
+#include <wtf/MathExtras.h>
+
+namespace WebCore {
+
+// Base structure for callback user data
+struct SVGTextQuery::Data {
+    Data()
+        : isVerticalText(false)
+        , processedCharacters(0)
+        , textRenderer(0)
+        , textBox(0)
+    {
+    }
+
+    bool isVerticalText;
+    unsigned processedCharacters;
+    RenderSVGInlineText* textRenderer;
+    const SVGInlineTextBox* textBox;
+};
+
+static inline InlineFlowBox* flowBoxForRenderer(RenderObject* renderer)
+{
+    if (!renderer)
+        return 0;
+
+    if (renderer->isRenderBlock()) {
+        // If we're given a block element, it has to be a RenderSVGText.
+        ASSERT(renderer->isSVGText());
+        RenderBlock* renderBlock = toRenderBlock(renderer);
+
+        // RenderSVGText only ever contains a single line box.
+        InlineFlowBox* flowBox = renderBlock->firstLineBox();
+        ASSERT(flowBox == renderBlock->lastLineBox());
+        return flowBox;
+    }
+
+    if (renderer->isRenderInline()) {
+        // We're given a RenderSVGInline or objects that derive from it (RenderSVGTSpan / RenderSVGTextPath)
+        RenderInline* renderInline = toRenderInline(renderer);
+
+        // RenderSVGInline only ever contains a single line box.
+        InlineFlowBox* flowBox = renderInline->firstLineBox();
+        ASSERT(flowBox == renderInline->lastLineBox());
+        return flowBox;
+    }
+
+    ASSERT_NOT_REACHED();
+    return 0;
+}
+
+static inline float mapLengthThroughFragmentTransformation(const SVGTextFragment& fragment, bool isVerticalText, float length)
+{
+    if (fragment.transform.isIdentity())
+        return length;
+
+    if (isVerticalText)
+        return narrowPrecisionToFloat(static_cast<double>(length) * fragment.transform.yScale());
+
+    return narrowPrecisionToFloat(static_cast<double>(length) * fragment.transform.xScale());
+}
+
+SVGTextQuery::SVGTextQuery(RenderObject* renderer)
+{
+    collectTextBoxesInFlowBox(flowBoxForRenderer(renderer));
+}
+
+void SVGTextQuery::collectTextBoxesInFlowBox(InlineFlowBox* flowBox)
+{
+    if (!flowBox)
+        return;
+
+    for (InlineBox* child = flowBox->firstChild(); child; child = child->nextOnLine()) {
+        if (child->isInlineFlowBox()) {
+            // Skip generated content.
+            if (!child->renderer()->node())
+                continue;
+
+            collectTextBoxesInFlowBox(static_cast<InlineFlowBox*>(child));
+            continue;
+        }
+
+        ASSERT(child->isSVGInlineTextBox());
+        m_textBoxes.append(static_cast<SVGInlineTextBox*>(child));
+    }
+}
+
+bool SVGTextQuery::executeQuery(Data* queryData, ProcessTextFragmentCallback fragmentCallback) const
+{
+    ASSERT(!m_textBoxes.isEmpty());
+
+    unsigned processedCharacters = 0;
+    unsigned textBoxCount = m_textBoxes.size();
+
+    // Loop over all text boxes
+    for (unsigned textBoxPosition = 0; textBoxPosition < textBoxCount; ++textBoxPosition) {
+        queryData->textBox = m_textBoxes.at(textBoxPosition);
+        queryData->textRenderer = toRenderSVGInlineText(queryData->textBox->textRenderer());
+        ASSERT(queryData->textRenderer);
+        ASSERT(queryData->textRenderer->style());
+        ASSERT(queryData->textRenderer->style()->svgStyle());
+
+        queryData->isVerticalText = queryData->textRenderer->style()->svgStyle()->isVerticalWritingMode();
+        const Vector<SVGTextFragment>& fragments = queryData->textBox->textFragments();
+    
+        // Loop over all text fragments in this text box, firing a callback for each.
+        unsigned fragmentCount = fragments.size();
+        for (unsigned i = 0; i < fragmentCount; ++i) {
+            const SVGTextFragment& fragment = fragments.at(i);
+            if ((this->*fragmentCallback)(queryData, fragment))
+                return true;
+
+            processedCharacters += fragment.length;
+        }
+
+        queryData->processedCharacters = processedCharacters;
+    }
+
+    return false;
+}
+
+bool SVGTextQuery::mapStartEndPositionsIntoFragmentCoordinates(Data* queryData, const SVGTextFragment& fragment, int& startPosition, int& endPosition) const
+{
+    // Reuse the same logic used for text selection & painting, to map our query start/length into start/endPositions of the current text fragment.
+    startPosition -= queryData->processedCharacters;
+    endPosition -= queryData->processedCharacters;
+
+    if (startPosition >= endPosition || startPosition < 0 || endPosition < 0)
+        return false;
+
+    modifyStartEndPositionsRespectingLigatures(queryData, startPosition, endPosition);
+    if (!queryData->textBox->mapStartEndPositionsIntoFragmentCoordinates(fragment, startPosition, endPosition))
+        return false;
+
+    ASSERT(startPosition < endPosition);
+    return true;
+}
+
+void SVGTextQuery::modifyStartEndPositionsRespectingLigatures(Data* queryData, int& startPosition, int& endPosition) const
+{
+    const SVGTextLayoutAttributes& layoutAttributes = queryData->textRenderer->layoutAttributes();
+    const Vector<float>& xValues = layoutAttributes.xValues();
+    const Vector<SVGTextMetrics>& textMetricsValues = layoutAttributes.textMetricsValues();
+
+    unsigned boxStart = queryData->textBox->start();
+    unsigned boxLength = queryData->textBox->len();
+
+    unsigned textMetricsOffset = 0;
+    unsigned textMetricsSize = textMetricsValues.size();
+
+    unsigned positionOffset = 0;
+    unsigned positionSize = xValues.size();
+
+    bool alterStartPosition = true;
+    bool alterEndPosition = true;
+
+    int lastPositionOffset = -1;
+    for (; textMetricsOffset < textMetricsSize && positionOffset < positionSize; ++textMetricsOffset) {
+        const SVGTextMetrics& metrics = textMetricsValues.at(textMetricsOffset);
+
+        // Advance to text box start location.
+        if (positionOffset < boxStart) {
+            positionOffset += metrics.length();
+            continue;
+        }
+
+        // Stop if we've finished processing this text box.
+        if (positionOffset >= boxStart + boxLength)
+            break;
+
+        // If the start position maps to a character in the metrics list, we don't need to modify it.
+        if (startPosition == static_cast<int>(positionOffset))
+            alterStartPosition = false;
+
+        // If the start position maps to a character in the metrics list, we don't need to modify it.
+        if (endPosition == static_cast<int>(positionOffset))
+            alterEndPosition = false;
+
+        // Detect ligatures.
+        if (lastPositionOffset != -1 && lastPositionOffset - positionOffset > 1) {
+            if (alterStartPosition && startPosition > lastPositionOffset && startPosition < static_cast<int>(positionOffset)) {
+                startPosition = lastPositionOffset;
+                alterStartPosition = false;
+            }
+
+            if (alterEndPosition && endPosition > lastPositionOffset && endPosition < static_cast<int>(positionOffset)) {
+                endPosition = positionOffset;
+                alterEndPosition = false;
+            }
+        }
+
+        if (!alterStartPosition && !alterEndPosition)
+            break;
+
+        lastPositionOffset = positionOffset;
+        positionOffset += metrics.length();
+    }
+
+    if (!alterStartPosition && !alterEndPosition)
+        return;
+
+    if (lastPositionOffset != -1 && lastPositionOffset - positionOffset > 1) {
+        if (alterStartPosition && startPosition > lastPositionOffset && startPosition < static_cast<int>(positionOffset)) {
+            startPosition = lastPositionOffset;
+            alterStartPosition = false;
+        }
+
+        if (alterEndPosition && endPosition > lastPositionOffset && endPosition < static_cast<int>(positionOffset)) {
+            endPosition = positionOffset;
+            alterEndPosition = false;
+        }
+    }
+}
+
+// numberOfCharacters() implementation
+bool SVGTextQuery::numberOfCharactersCallback(Data*, const SVGTextFragment&) const
+{
+    // no-op
+    return false;
+}
+
+unsigned SVGTextQuery::numberOfCharacters() const
+{
+    if (m_textBoxes.isEmpty())
+        return 0;
+
+    Data data;
+    executeQuery(&data, &SVGTextQuery::numberOfCharactersCallback);
+    return data.processedCharacters;
+}
+
+// textLength() implementation
+struct TextLengthData : SVGTextQuery::Data {
+    TextLengthData()
+        : textLength(0)
+    {
+    }
+
+    float textLength;
+};
+
+bool SVGTextQuery::textLengthCallback(Data* queryData, const SVGTextFragment& fragment) const
+{
+    TextLengthData* data = static_cast<TextLengthData*>(queryData);
+
+    float fragmentLength = queryData->isVerticalText ? fragment.height : fragment.width;
+    data->textLength += mapLengthThroughFragmentTransformation(fragment, queryData->isVerticalText, fragmentLength);
+    return false;
+}
+
+float SVGTextQuery::textLength() const
+{
+    if (m_textBoxes.isEmpty())
+        return 0;
+
+    TextLengthData data;
+    executeQuery(&data, &SVGTextQuery::textLengthCallback);
+    return data.textLength;
+}
+
+// subStringLength() implementation
+struct SubStringLengthData : SVGTextQuery::Data {
+    SubStringLengthData(unsigned queryStartPosition, unsigned queryLength)
+        : startPosition(queryStartPosition)
+        , length(queryLength)
+        , subStringLength(0)
+    {
+    }
+
+    unsigned startPosition;
+    unsigned length;
+
+    float subStringLength;
+};
+
+bool SVGTextQuery::subStringLengthCallback(Data* queryData, const SVGTextFragment& fragment) const
+{
+    SubStringLengthData* data = static_cast<SubStringLengthData*>(queryData);
+
+    int startPosition = data->startPosition;
+    int endPosition = startPosition + data->length;
+    if (!mapStartEndPositionsIntoFragmentCoordinates(queryData, fragment, startPosition, endPosition))
+        return false;
+
+    SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textRenderer, fragment.positionListOffset + startPosition, endPosition - startPosition);
+    float fragmentLength = queryData->isVerticalText ? metrics.height() : metrics.width();
+
+    data->subStringLength += mapLengthThroughFragmentTransformation(fragment, queryData->isVerticalText, fragmentLength);
+    return false;
+}
+
+float SVGTextQuery::subStringLength(unsigned startPosition, unsigned length) const
+{
+    if (m_textBoxes.isEmpty())
+        return 0;
+
+    SubStringLengthData data(startPosition, length);
+    executeQuery(&data, &SVGTextQuery::subStringLengthCallback);
+    return data.subStringLength;
+}
+
+// startPositionOfCharacter() implementation
+struct StartPositionOfCharacterData : SVGTextQuery::Data {
+    StartPositionOfCharacterData(unsigned queryPosition)
+        : position(queryPosition)
+    {
+    }
+
+    unsigned position;
+    FloatPoint startPosition;
+};
+
+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->textRenderer, fragment.positionListOffset, startPosition);
+        if (queryData->isVerticalText)
+            data->startPosition.move(0, metrics.height());
+        else
+            data->startPosition.move(metrics.width(), 0);
+    }
+
+    if (fragment.transform.isIdentity())
+        return true;
+
+    data->startPosition = fragment.transform.mapPoint(data->startPosition);
+    return true;
+}
+
+FloatPoint SVGTextQuery::startPositionOfCharacter(unsigned position) const
+{
+    if (m_textBoxes.isEmpty())
+        return FloatPoint();
+
+    StartPositionOfCharacterData data(position);
+    executeQuery(&data, &SVGTextQuery::startPositionOfCharacterCallback);
+    return data.startPosition;
+}
+
+// endPositionOfCharacter() implementation
+struct EndPositionOfCharacterData : SVGTextQuery::Data {
+    EndPositionOfCharacterData(unsigned queryPosition)
+        : position(queryPosition)
+    {
+    }
+
+    unsigned position;
+    FloatPoint endPosition;
+};
+
+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->textRenderer, fragment.positionListOffset, startPosition + 1);
+    if (queryData->isVerticalText)
+        data->endPosition.move(0, metrics.height());
+    else
+        data->endPosition.move(metrics.width(), 0);
+
+    if (fragment.transform.isIdentity())
+        return true;
+
+    data->endPosition = fragment.transform.mapPoint(data->endPosition);
+    return true;
+}
+
+FloatPoint SVGTextQuery::endPositionOfCharacter(unsigned position) const
+{
+    if (m_textBoxes.isEmpty())
+        return FloatPoint();
+
+    EndPositionOfCharacterData data(position);
+    executeQuery(&data, &SVGTextQuery::endPositionOfCharacterCallback);
+    return data.endPosition;
+}
+
+// rotationOfCharacter() implementation
+struct RotationOfCharacterData : SVGTextQuery::Data {
+    RotationOfCharacterData(unsigned queryPosition)
+        : position(queryPosition)
+        , rotation(0)
+    {
+    }
+
+    unsigned position;
+    float rotation;
+};
+
+bool SVGTextQuery::rotationOfCharacterCallback(Data* queryData, const SVGTextFragment& fragment) const
+{
+    RotationOfCharacterData* data = static_cast<RotationOfCharacterData*>(queryData);
+
+    int startPosition = data->position;
+    int endPosition = startPosition + 1;
+    if (!mapStartEndPositionsIntoFragmentCoordinates(queryData, fragment, startPosition, endPosition))
+        return false;
+
+    AffineTransform newTransform(fragment.transform);
+    newTransform.scale(1 / fragment.transform.xScale(), 1 / fragment.transform.yScale());
+    data->rotation = narrowPrecisionToFloat(rad2deg(atan2(newTransform.b(), newTransform.a())));
+    return true;
+}
+
+float SVGTextQuery::rotationOfCharacter(unsigned position) const
+{
+    if (m_textBoxes.isEmpty())
+        return 0;
+
+    RotationOfCharacterData data(position);
+    executeQuery(&data, &SVGTextQuery::rotationOfCharacterCallback);
+    return data.rotation;
+}
+
+// extentOfCharacter() implementation
+struct ExtentOfCharacterData : SVGTextQuery::Data {
+    ExtentOfCharacterData(unsigned queryPosition)
+        : position(queryPosition)
+    {
+    }
+
+    unsigned position;
+    FloatRect extent;
+};
+
+static inline void calculateGlyphBoundaries(SVGTextQuery::Data* queryData, const SVGTextFragment& fragment, int startPosition, FloatRect& extent)
+{
+    extent.setLocation(FloatPoint(fragment.x, fragment.y - queryData->textRenderer->style()->font().ascent()));
+
+    if (startPosition) {
+        SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textRenderer, fragment.positionListOffset, startPosition);
+        if (queryData->isVerticalText)
+            extent.move(0, metrics.height());
+        else
+            extent.move(metrics.width(), 0);
+    }
+
+    SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(queryData->textRenderer, fragment.positionListOffset + startPosition, 1);
+    extent.setSize(FloatSize(metrics.width(), metrics.height()));
+
+    if (fragment.transform.isIdentity())
+        return;
+
+    extent = fragment.transform.mapRect(extent);
+}
+
+bool SVGTextQuery::extentOfCharacterCallback(Data* queryData, const SVGTextFragment& fragment) const
+{
+    ExtentOfCharacterData* data = static_cast<ExtentOfCharacterData*>(queryData);
+
+    int startPosition = data->position;
+    int endPosition = startPosition + 1;
+    if (!mapStartEndPositionsIntoFragmentCoordinates(queryData, fragment, startPosition, endPosition))
+        return false;
+
+    calculateGlyphBoundaries(queryData, fragment, startPosition, data->extent);
+    return true;
+}
+
+FloatRect SVGTextQuery::extentOfCharacter(unsigned position) const
+{
+    if (m_textBoxes.isEmpty())
+        return FloatRect();
+
+    ExtentOfCharacterData data(position);
+    executeQuery(&data, &SVGTextQuery::extentOfCharacterCallback);
+    return data.extent;
+}
+
+// characterNumberAtPosition() implementation
+struct CharacterNumberAtPositionData : SVGTextQuery::Data {
+    CharacterNumberAtPositionData(const FloatPoint& queryPosition)
+        : position(queryPosition)
+    {
+    }
+
+    FloatPoint position;
+};
+
+bool SVGTextQuery::characterNumberAtPositionCallback(Data* queryData, const SVGTextFragment& fragment) const
+{
+    CharacterNumberAtPositionData* data = static_cast<CharacterNumberAtPositionData*>(queryData);
+
+    FloatRect extent;
+    for (unsigned i = 0; i < fragment.length; ++i) {
+        int startPosition = data->processedCharacters + i;
+        int endPosition = startPosition + 1;
+        if (!mapStartEndPositionsIntoFragmentCoordinates(queryData, fragment, startPosition, endPosition))
+            continue;
+
+        calculateGlyphBoundaries(queryData, fragment, startPosition, extent);
+        if (extent.contains(data->position)) {
+            data->processedCharacters += i;
+            return true;
+        }
+    }
+
+    return false;
+}
+
+int SVGTextQuery::characterNumberAtPosition(const FloatPoint& position) const
+{
+    if (m_textBoxes.isEmpty())
+        return -1;
+
+    CharacterNumberAtPositionData data(position);
+    if (!executeQuery(&data, &SVGTextQuery::characterNumberAtPositionCallback))
+        return -1;
+
+    return data.processedCharacters;
+}
+
+}
+
+#endif