void SVGTextLayoutEngine::layoutTextOnLineOrPath(SVGInlineTextBox* textBox, LineLayoutSVGInlineText textLineLayout, const ComputedStyle& style)
{
    if (m_inPathLayout && !m_textPathCalculator)
        return;

    // Find the start of the current text box in the metrics list.
    m_visualMetricsIterator.advanceToTextStart(&textLineLayout, textBox->start());

    const Font& font = style.font();

    SVGTextLayoutEngineSpacing spacingLayout(font, style.effectiveZoom());
    SVGTextLayoutEngineBaseline baselineLayout(font, style.effectiveZoom());

    bool didStartTextFragment = false;
    bool applySpacingToNextCharacter = false;

    float lastAngle = 0;
    float baselineShift = baselineLayout.calculateBaselineShift(style);
    baselineShift -= baselineLayout.calculateAlignmentBaselineShift(m_isVerticalText, textLineLayout);

    // Main layout algorithm.
    const unsigned boxEndOffset = textBox->start() + textBox->len();
    while (!m_visualMetricsIterator.isAtEnd() && m_visualMetricsIterator.characterOffset() < boxEndOffset) {
        const SVGTextMetrics& visualMetrics = m_visualMetricsIterator.metrics();
        if (visualMetrics.isEmpty()) {
            m_visualMetricsIterator.next();
            continue;
        }

        SVGTextLayoutAttributes* logicalAttributes = nullptr;
        if (!currentLogicalCharacterAttributes(logicalAttributes))
            break;

        ASSERT(logicalAttributes);
        SVGTextMetrics logicalMetrics(SVGTextMetrics::SkippedSpaceMetrics);
        if (!currentLogicalCharacterMetrics(logicalAttributes, logicalMetrics))
            break;

        SVGCharacterDataMap& characterDataMap = logicalAttributes->characterDataMap();
        SVGCharacterData data;
        SVGCharacterDataMap::iterator it = characterDataMap.find(m_logicalCharacterOffset + 1);
        if (it != characterDataMap.end())
            data = it->value;

        float x = data.x;
        float y = data.y;

        // When we've advanced to the box start offset, determine using the original x/y values,
        // whether this character starts a new text chunk, before doing any further processing.
        if (m_visualMetricsIterator.characterOffset() == textBox->start())
            textBox->setStartsNewTextChunk(logicalAttributes->context()->characterStartsNewTextChunk(m_logicalCharacterOffset));

        float angle = SVGTextLayoutAttributes::isEmptyValue(data.rotate) ? 0 : data.rotate;

        // Calculate glyph orientation angle.
        // Font::width() calculates the resolved FontOrientation for each character,
        // but is not exposed today to avoid the API complexity.
        UChar32 currentCharacter = textLineLayout.codepointAt(m_visualMetricsIterator.characterOffset());
        FontOrientation fontOrientation = font.fontDescription().orientation();
        fontOrientation = adjustOrientationForCharacterInMixedVertical(fontOrientation, currentCharacter);

        // Calculate glyph advance.
        // Shaping engine takes care of x/y orientation shifts for different fontOrientation values.
        float glyphAdvance = visualMetrics.advance(fontOrientation);

        // Assign current text position to x/y values, if needed.
        updateCharacterPositionIfNeeded(x, y);

        // Apply dx/dy value adjustments to current text position, if needed.
        updateRelativePositionAdjustmentsIfNeeded(data.dx, data.dy);

        // Calculate CSS 'letter-spacing' and 'word-spacing' for next character, if needed.
        float spacing = spacingLayout.calculateCSSSpacing(currentCharacter);

        float textPathOffset = 0;
        float textPathShiftX = 0;
        float textPathShiftY = 0;
        if (m_inPathLayout) {
            float scaledGlyphAdvance = glyphAdvance * m_textPathScaling;
            if (m_isVerticalText) {
                // If there's an absolute y position available, it marks the beginning of a new position along the path.
                if (!SVGTextLayoutAttributes::isEmptyValue(y))
                    m_textPathCurrentOffset = y + m_textPathStartOffset;

                m_textPathCurrentOffset += m_dy;
                m_dy = 0;

                // Apply dx/dy correction and setup translations that move to the glyph midpoint.
                textPathShiftX += m_dx + baselineShift;
                textPathShiftY -= scaledGlyphAdvance / 2;
            } else {
                // If there's an absolute x position available, it marks the beginning of a new position along the path.
                if (!SVGTextLayoutAttributes::isEmptyValue(x))
                    m_textPathCurrentOffset = x + m_textPathStartOffset;

                m_textPathCurrentOffset += m_dx;
                m_dx = 0;

                // Apply dx/dy correction and setup translations that move to the glyph midpoint.
                textPathShiftX -= scaledGlyphAdvance / 2;
                textPathShiftY += m_dy - baselineShift;
            }

            // Calculate current offset along path.
            textPathOffset = m_textPathCurrentOffset + scaledGlyphAdvance / 2;

            // Move to next character.
            m_textPathCurrentOffset += scaledGlyphAdvance + m_textPathSpacing + spacing * m_textPathScaling;

            // Skip character, if we're before the path.
            if (textPathOffset < 0) {
                advanceToNextLogicalCharacter(logicalMetrics);
                m_visualMetricsIterator.next();
                continue;
            }

            // Stop processing, if the next character lies behind the path.
            if (textPathOffset > m_textPathLength)
                break;

            FloatPoint point;
            bool ok = m_textPathCalculator->pointAndNormalAtLength(textPathOffset, point, angle);
            ASSERT_UNUSED(ok, ok);
            x = point.x();
            y = point.y();

            // For vertical text on path, the actual angle has to be rotated 90 degrees anti-clockwise, not the orientation angle!
            if (m_isVerticalText)
                angle -= 90;
        } else {
            // Apply all previously calculated shift values.
            if (m_isVerticalText)
                x += baselineShift;
            else
                y -= baselineShift;

            x += m_dx;
            y += m_dy;
        }

        // Determine whether we have to start a new fragment.
        bool shouldStartNewFragment = m_dx || m_dy || m_isVerticalText || m_inPathLayout || angle || angle != lastAngle
            || applySpacingToNextCharacter || m_textLengthSpacingInEffect;

        // If we already started a fragment, close it now.
        if (didStartTextFragment && shouldStartNewFragment) {
            applySpacingToNextCharacter = false;
            recordTextFragment(textBox);
        }

        // Eventually start a new fragment, if not yet done.
        if (!didStartTextFragment || shouldStartNewFragment) {
            ASSERT(!m_currentTextFragment.characterOffset);
            ASSERT(!m_currentTextFragment.length);

            didStartTextFragment = true;
            m_currentTextFragment.characterOffset = m_visualMetricsIterator.characterOffset();
            m_currentTextFragment.metricsListOffset = m_visualMetricsIterator.metricsListOffset();
            m_currentTextFragment.x = x;
            m_currentTextFragment.y = y;

            // Build fragment transformation.
            if (angle)
                m_currentTextFragment.transform.rotate(angle);

            if (textPathShiftX || textPathShiftY)
                m_currentTextFragment.transform.translate(textPathShiftX, textPathShiftY);

            // In vertical text, always rotate by 90 degrees regardless of fontOrientation.
            // Shaping engine takes care of the necessary orientation.
            if (m_isVerticalText)
                m_currentTextFragment.transform.rotate(90);

            m_currentTextFragment.isTextOnPath = m_inPathLayout && m_textPathScaling != 1;
            if (m_currentTextFragment.isTextOnPath) {
                if (m_isVerticalText)
                    m_currentTextFragment.lengthAdjustTransform.scaleNonUniform(1, m_textPathScaling);
                else
                    m_currentTextFragment.lengthAdjustTransform.scaleNonUniform(m_textPathScaling, 1);
            }
        }

        // Update current text position, after processing of the current character finished.
        if (m_inPathLayout) {
            updateCurrentTextPosition(x, y, glyphAdvance);
        } else {
            // Apply CSS 'kerning', 'letter-spacing' and 'word-spacing' to next character, if needed.
            if (spacing)
                applySpacingToNextCharacter = true;

            float xNew = x - m_dx;
            float yNew = y - m_dy;

            if (m_isVerticalText)
                xNew -= baselineShift;
            else
                yNew += baselineShift;

            updateCurrentTextPosition(xNew, yNew, glyphAdvance + spacing);
        }

        advanceToNextLogicalCharacter(logicalMetrics);
        m_visualMetricsIterator.next();
        lastAngle = angle;
    }

    if (!didStartTextFragment)
        return;

    // Close last open fragment, if needed.
    recordTextFragment(textBox);
}
示例#2
0
void SVGTextLayoutEngine::layoutTextOnLineOrPath(SVGInlineTextBox* textBox, RenderSVGInlineText* text, const RenderStyle* style)
{
    if (m_inPathLayout && m_textPath.isEmpty())
        return;

    SVGElement* lengthContext = toSVGElement(text->parent()->element());
    
    RenderObject* textParent = text->parent();
    bool definesTextLength = textParent ? parentDefinesTextLength(textParent) : false;

    const SVGRenderStyle* svgStyle = style->svgStyle();
    ASSERT(svgStyle);

    m_visualMetricsListOffset = 0;
    m_visualCharacterOffset = 0;

    Vector<SVGTextMetrics>& visualMetricsValues = text->layoutAttributes()->textMetricsValues();
    ASSERT(!visualMetricsValues.isEmpty());

    const UChar* characters = text->characters();
    const Font& font = style->font();

    SVGTextLayoutEngineSpacing spacingLayout(font);
    SVGTextLayoutEngineBaseline baselineLayout(font);

    bool didStartTextFragment = false;
    bool applySpacingToNextCharacter = false;

    float lastAngle = 0;
    float baselineShift = baselineLayout.calculateBaselineShift(svgStyle, lengthContext);
    baselineShift -= baselineLayout.calculateAlignmentBaselineShift(m_isVerticalText, text);

    // Main layout algorithm.
    while (true) {
        // Find the start of the current text box in this list, respecting ligatures.
        SVGTextMetrics visualMetrics(SVGTextMetrics::SkippedSpaceMetrics);
        if (!currentVisualCharacterMetrics(textBox, visualMetricsValues, visualMetrics))
            break;

        if (visualMetrics.isEmpty()) {
            advanceToNextVisualCharacter(visualMetrics);
            continue;
        }

        SVGTextLayoutAttributes* logicalAttributes = 0;
        if (!currentLogicalCharacterAttributes(logicalAttributes))
            break;

        ASSERT(logicalAttributes);
        SVGTextMetrics logicalMetrics(SVGTextMetrics::SkippedSpaceMetrics);
        if (!currentLogicalCharacterMetrics(logicalAttributes, logicalMetrics))
            break;

        SVGCharacterDataMap& characterDataMap = logicalAttributes->characterDataMap();
        SVGCharacterData data;
        SVGCharacterDataMap::iterator it = characterDataMap.find(m_logicalCharacterOffset + 1);
        if (it != characterDataMap.end())
            data = it->value;

        float x = data.x;
        float y = data.y;

        // When we've advanced to the box start offset, determine using the original x/y values,
        // whether this character starts a new text chunk, before doing any further processing.
        if (m_visualCharacterOffset == textBox->start())
            textBox->setStartsNewTextChunk(logicalAttributes->context()->characterStartsNewTextChunk(m_logicalCharacterOffset));

        float angle = data.rotate == SVGTextLayoutAttributes::emptyValue() ? 0 : data.rotate;

        // Calculate glyph orientation angle.
        const UChar* currentCharacter = characters + m_visualCharacterOffset;
        float orientationAngle = baselineLayout.calculateGlyphOrientationAngle(m_isVerticalText, svgStyle, *currentCharacter);

        // Calculate glyph advance & x/y orientation shifts.
        float xOrientationShift = 0;
        float yOrientationShift = 0;
        float glyphAdvance = baselineLayout.calculateGlyphAdvanceAndOrientation(m_isVerticalText, visualMetrics, orientationAngle, xOrientationShift, yOrientationShift);

        // Assign current text position to x/y values, if needed.
        updateCharacerPositionIfNeeded(x, y);

        // Apply dx/dy value adjustments to current text position, if needed.
        updateRelativePositionAdjustmentsIfNeeded(data.dx, data.dy);

        // Calculate SVG Fonts kerning, if needed.
        float kerning = spacingLayout.calculateSVGKerning(m_isVerticalText, visualMetrics.glyph());

        // Calculate CSS 'kerning', 'letter-spacing' and 'word-spacing' for next character, if needed.
        float spacing = spacingLayout.calculateCSSKerningAndSpacing(svgStyle, lengthContext, currentCharacter);

        float textPathOffset = 0;
        if (m_inPathLayout) {
            float scaledGlyphAdvance = glyphAdvance * m_textPathScaling;
            if (m_isVerticalText) {
                // If there's an absolute y position available, it marks the beginning of a new position along the path.
                if (y != SVGTextLayoutAttributes::emptyValue())
                    m_textPathCurrentOffset = y + m_textPathStartOffset;

                m_textPathCurrentOffset += m_dy - kerning;
                m_dy = 0;

                // Apply dx/dy correction and setup translations that move to the glyph midpoint.
                xOrientationShift += m_dx + baselineShift;
                yOrientationShift -= scaledGlyphAdvance / 2;
            } else {
                // If there's an absolute x position available, it marks the beginning of a new position along the path.
                if (x != SVGTextLayoutAttributes::emptyValue())
                    m_textPathCurrentOffset = x + m_textPathStartOffset;

                m_textPathCurrentOffset += m_dx - kerning;
                m_dx = 0;

                // Apply dx/dy correction and setup translations that move to the glyph midpoint.
                xOrientationShift -= scaledGlyphAdvance / 2;
                yOrientationShift += m_dy - baselineShift;
            }

            // Calculate current offset along path.
            textPathOffset = m_textPathCurrentOffset + scaledGlyphAdvance / 2;

            // Move to next character.
            m_textPathCurrentOffset += scaledGlyphAdvance + m_textPathSpacing + spacing * m_textPathScaling;

            // Skip character, if we're before the path.
            if (textPathOffset < 0) {
                advanceToNextLogicalCharacter(logicalMetrics);
                advanceToNextVisualCharacter(visualMetrics);
                continue;
            }

            // Stop processing, if the next character lies behind the path.
            if (textPathOffset > m_textPathLength)
                break;

            bool ok = false;
            FloatPoint point = m_textPath.pointAtLength(textPathOffset, ok);
            ASSERT(ok);

            x = point.x();
            y = point.y();
            angle = m_textPath.normalAngleAtLength(textPathOffset, ok);
            ASSERT(ok);

            // For vertical text on path, the actual angle has to be rotated 90 degrees anti-clockwise, not the orientation angle!
            if (m_isVerticalText)
                angle -= 90;
        } else {
            // Apply all previously calculated shift values.
            if (m_isVerticalText) {
                x += baselineShift;
                y -= kerning;
            } else {
                x -= kerning;
                y -= baselineShift;
            }

            x += m_dx;
            y += m_dy;
        }

        // Determine whether we have to start a new fragment.
        bool shouldStartNewFragment = m_dx || m_dy || m_isVerticalText || m_inPathLayout || angle || angle != lastAngle
            || orientationAngle || kerning || applySpacingToNextCharacter || definesTextLength;

        // If we already started a fragment, close it now.
        if (didStartTextFragment && shouldStartNewFragment) {
            applySpacingToNextCharacter = false;
            recordTextFragment(textBox, visualMetricsValues);
        }

        // Eventually start a new fragment, if not yet done.
        if (!didStartTextFragment || shouldStartNewFragment) {
            ASSERT(!m_currentTextFragment.characterOffset);
            ASSERT(!m_currentTextFragment.length);

            didStartTextFragment = true;
            m_currentTextFragment.characterOffset = m_visualCharacterOffset;
            m_currentTextFragment.metricsListOffset = m_visualMetricsListOffset;
            m_currentTextFragment.x = x;
            m_currentTextFragment.y = y;

            // Build fragment transformation.
            if (angle)
                m_currentTextFragment.transform.rotate(angle);

            if (xOrientationShift || yOrientationShift)
                m_currentTextFragment.transform.translate(xOrientationShift, yOrientationShift);

            if (orientationAngle)
                m_currentTextFragment.transform.rotate(orientationAngle);

            m_currentTextFragment.isTextOnPath = m_inPathLayout && m_textPathScaling != 1;
            if (m_currentTextFragment.isTextOnPath) {
                if (m_isVerticalText)
                    m_currentTextFragment.lengthAdjustTransform.scaleNonUniform(1, m_textPathScaling);
                else
                    m_currentTextFragment.lengthAdjustTransform.scaleNonUniform(m_textPathScaling, 1);
            }
        }

        // Update current text position, after processing of the current character finished.
        if (m_inPathLayout)
            updateCurrentTextPosition(x, y, glyphAdvance);
        else {
            // Apply CSS 'kerning', 'letter-spacing' and 'word-spacing' to next character, if needed.
            if (spacing)
                applySpacingToNextCharacter = true;

            float xNew = x - m_dx;
            float yNew = y - m_dy;

            if (m_isVerticalText)
                xNew -= baselineShift;
            else
                yNew += baselineShift;

            updateCurrentTextPosition(xNew, yNew, glyphAdvance + spacing);
        }

        advanceToNextLogicalCharacter(logicalMetrics);
        advanceToNextVisualCharacter(visualMetrics);
        lastAngle = angle;
    }

    if (!didStartTextFragment)
        return;

    // Close last open fragment, if needed.
    recordTextFragment(textBox, visualMetricsValues);
}