C++ RenderSVGInlineText类代码示例

void SVGTextLayoutAttributesBuilder::buildLayoutScopes(RenderObject* start, unsigned& atCharacter, UChar& lastCharacter)
{
    for (RenderObject* child = start->firstChild(); child; child = child->nextSibling()) { 
        if (child->isSVGInlineText()) {
            RenderSVGInlineText* text = toRenderSVGInlineText(child);

            if (!shouldPreserveAllWhiteSpace(text->style())) {
                const UChar* characters = text->characters();
                unsigned textLength = text->textLength();    
                for (unsigned textPosition = 0; textPosition < textLength; ++textPosition) {
                    const UChar& currentCharacter = characters[textPosition];
                    if (characterIsSpace(currentCharacter) && characterIsSpaceOrNull(lastCharacter))
                        continue;

                    lastCharacter = currentCharacter;
                    ++atCharacter;
                }
            } else
                atCharacter += text->textLength();

            continue;
        }

        if (!child->isSVGInline())
            continue;

        unsigned textContentStart = atCharacter;
        buildLayoutScopes(child, atCharacter, lastCharacter);

        LayoutScope scope;
        buildLayoutScope(scope, child, textContentStart, atCharacter - textContentStart);
        m_scopes.append(scope);
    }
}

void writeSVGInlineText(TextStream& ts, const RenderSVGInlineText& text, int indent)
{
    writeStandardPrefix(ts, text, indent);
    ts << " " << enclosingIntRect(FloatRect(text.firstRunOrigin(), text.floatLinesBoundingBox().size())) << "\n";
    writeResources(ts, text, indent);
    writeSVGInlineTextBoxes(ts, text, indent);
}

static inline bool findPreviousAndNextAttributes(RenderObject* root, RenderSVGInlineText* locateElement, SVGTextLayoutAttributes*& previous, SVGTextLayoutAttributes*& next)
{
    ASSERT(root);
    ASSERT(locateElement);
    bool stopAfterNext = false;
    RenderObject* current = root->firstChild();
    while (current) {
        if (current->isSVGInlineText()) {
            RenderSVGInlineText* text = toRenderSVGInlineText(current);
            if (locateElement != text) {
                if (stopAfterNext) {
                    next = text->layoutAttributes();
                    return true;
                }

                previous = text->layoutAttributes();
            } else {
                stopAfterNext = true;
            }
        } else if (current->isSVGInline()) {
            // Descend into text content (if possible).
            if (RenderObject* child = current->firstChild()) {
                current = child;
                continue;
            }
        }

        current = current->nextInPreOrderAfterChildren(root);
    }
    return false;
}

FloatRect SVGInlineTextBox::selectionRectForTextFragment(const SVGTextFragment& fragment, int startPosition, int endPosition, RenderStyle* style)
{
    ASSERT(startPosition < endPosition);
    ASSERT(style);

    FontCachePurgePreventer fontCachePurgePreventer;

    RenderSVGInlineText* textRenderer = toRenderSVGInlineText(this->textRenderer());
    ASSERT(textRenderer);

    float scalingFactor = textRenderer->scalingFactor();
    ASSERT(scalingFactor);

    const Font& scaledFont = textRenderer->scaledFont();
    const FontMetrics& scaledFontMetrics = scaledFont.fontMetrics();
    FloatPoint textOrigin(fragment.x, fragment.y);
    if (scalingFactor != 1)
        textOrigin.scale(scalingFactor, scalingFactor);

    textOrigin.move(0, -scaledFontMetrics.floatAscent());

    FloatRect selectionRect = scaledFont.selectionRectForText(constructTextRun(style, fragment), textOrigin, fragment.height * scalingFactor, startPosition, endPosition);
    if (scalingFactor == 1)
        return selectionRect;

    selectionRect.scale(1 / scalingFactor);
    return selectionRect;
}

FloatRect SVGInlineTextBox::calculateBoundaries() const
{
    FloatRect textRect;

    RenderSVGInlineText* textRenderer = toRenderSVGInlineText(this->textRenderer());
    ASSERT(textRenderer);

    float scalingFactor = textRenderer->scalingFactor();
    ASSERT(scalingFactor);

    float baseline = textRenderer->scaledFont().fontMetrics().floatAscent() / scalingFactor;

    AffineTransform fragmentTransform;
    unsigned textFragmentsSize = m_textFragments.size();
    for (unsigned i = 0; i < textFragmentsSize; ++i) {
        const SVGTextFragment& fragment = m_textFragments.at(i);
        FloatRect fragmentRect(fragment.x, fragment.y - baseline, fragment.width, fragment.height);
        fragment.buildFragmentTransform(fragmentTransform);
        if (!fragmentTransform.isIdentity())
            fragmentRect = fragmentTransform.mapRect(fragmentRect);

        textRect.unite(fragmentRect);
    }

    return textRect;
}

void RenderSVGText::subtreeChildWillBeRemoved(RenderObject* child, Vector<SVGTextLayoutAttributes*, 2>& affectedAttributes)
{
    ASSERT(child);
    if (!shouldHandleSubtreeMutations())
        return;

    checkLayoutAttributesConsistency(this, m_layoutAttributes);

    // The positioning elements cache depends on the size of each text renderer in the
    // subtree. If this changes, clear the cache. It's going to be rebuilt below.
    m_layoutAttributesBuilder.clearTextPositioningElements();
    if (m_layoutAttributes.isEmpty() || !child->isSVGInlineText())
        return;

    // This logic requires that the 'text' child is still inserted in the tree.
    RenderSVGInlineText* text = toRenderSVGInlineText(child);
    bool stopAfterNext = false;
    SVGTextLayoutAttributes* previous = 0;
    SVGTextLayoutAttributes* next = 0;
    if (!documentBeingDestroyed())
        findPreviousAndNextAttributes(this, text, stopAfterNext, previous, next);

    if (previous)
        affectedAttributes.append(previous);
    if (next)
        affectedAttributes.append(next);

    size_t position = m_layoutAttributes.find(text->layoutAttributes());
    ASSERT(position != notFound);
    m_layoutAttributes.remove(position);
}

static inline bool findPreviousAndNextAttributes(RenderObject* start, RenderSVGInlineText* locateElement, bool& stopAfterNext, SVGTextLayoutAttributes*& previous, SVGTextLayoutAttributes*& next)
{
    ASSERT(start);
    ASSERT(locateElement);
    // FIXME: Make this iterative.
    for (RenderObject* child = start->firstChild(); child; child = child->nextSibling()) {
        if (child->isSVGInlineText()) {
            RenderSVGInlineText* text = toRenderSVGInlineText(child);
            if (locateElement != text) {
                if (stopAfterNext) {
                    next = text->layoutAttributes();
                    return true;
                }

                previous = text->layoutAttributes();
                continue;
            }

            stopAfterNext = true;
            continue;
        }

        if (!child->isSVGInline())
            continue;

        if (findPreviousAndNextAttributes(child, locateElement, stopAfterNext, previous, next))
            return true;
    }

    return false;
}

void write(TextStream& ts, const RenderSVGInlineText& text, int indent)
{
    writeStandardPrefix(ts, text, indent);

    // Why not just linesBoundingBox()?
    ts << " " << FloatRect(text.firstRunOrigin(), text.linesBoundingBox().size()) << "\n";
    writeSVGInlineText(ts, text, indent);
}

void SVGInlineTextBox::paintTextWithShadows(GraphicsContext* context, RenderStyle* style, TextRun& textRun, const SVGTextFragment& fragment, int startPosition, int endPosition)
{
    RenderSVGInlineText* textRenderer = toRenderSVGInlineText(this->textRenderer());
    ASSERT(textRenderer);

    float scalingFactor = textRenderer->scalingFactor();
    ASSERT(scalingFactor);

    const Font& scaledFont = textRenderer->scaledFont();
    const ShadowData* shadow = style->textShadow();

    FloatPoint textOrigin(fragment.x, fragment.y);
    FloatSize textSize(fragment.width, fragment.height);

    if (scalingFactor != 1) {
        textOrigin.scale(scalingFactor, scalingFactor);
        textSize.scale(scalingFactor);
    }

    FloatRect shadowRect(FloatPoint(textOrigin.x(), textOrigin.y() - scaledFont.fontMetrics().floatAscent()), textSize);

    do {
        if (!prepareGraphicsContextForTextPainting(context, scalingFactor, textRun, style))
            break;

        FloatSize extraOffset;
        if (shadow)
            extraOffset = applyShadowToGraphicsContext(context, shadow, shadowRect, false /* stroked */, true /* opaque */, true /* horizontal */);

        AffineTransform originalTransform;
        if (scalingFactor != 1) {
            originalTransform = context->getCTM();

            AffineTransform newTransform = originalTransform;
            newTransform.scale(1 / scalingFactor);
            normalizeTransform(newTransform);

            context->setCTM(newTransform);
        }

        scaledFont.drawText(context, textRun, textOrigin + extraOffset, startPosition, endPosition);

        if (scalingFactor != 1)
            context->setCTM(originalTransform);

        restoreGraphicsContextAfterTextPainting(context, textRun);

        if (!shadow)
            break;

        if (shadow->next())
            context->restore();
        else
            context->clearShadow();

        shadow = shadow->next();
    } while (shadow);
}

static inline void writeSVGInlineTextBox(TextStream& ts, SVGInlineTextBox* textBox, int indent)
{
    Vector<SVGTextFragment>& fragments = textBox->textFragments();
    if (fragments.isEmpty())
        return;

    RenderSVGInlineText* textRenderer = toRenderSVGInlineText(textBox->textRenderer());
    ASSERT(textRenderer);

    const SVGRenderStyle* svgStyle = textRenderer->style()->svgStyle();
    String text = textBox->textRenderer()->text();

    unsigned fragmentsSize = fragments.size();
    for (unsigned i = 0; i < fragmentsSize; ++i) {
        SVGTextFragment& fragment = fragments.at(i);
        writeIndent(ts, indent + 1);

        unsigned startOffset = fragment.characterOffset;
        unsigned endOffset = fragment.characterOffset + fragment.length;

        // FIXME: Remove this hack, once the new text layout engine is completly landed. We want to preserve the old layout test results for now.
        ts << "chunk 1 ";
        ETextAnchor anchor = svgStyle->textAnchor();
        bool isVerticalText = svgStyle->isVerticalWritingMode();
        if (anchor == TA_MIDDLE) {
            ts << "(middle anchor";
            if (isVerticalText)
                ts << ", vertical";
            ts << ") ";
        } else if (anchor == TA_END) {
            ts << "(end anchor";
            if (isVerticalText)
                ts << ", vertical";
            ts << ") ";
        } else if (isVerticalText)
            ts << "(vertical) ";
        startOffset -= textBox->start();
        endOffset -= textBox->start();
        // </hack>

        ts << "text run " << i + 1 << " at (" << fragment.x << "," << fragment.y << ")";
        ts << " startOffset " << startOffset << " endOffset " << endOffset;
        if (isVerticalText)
            ts << " height " << fragment.height;
        else
            ts << " width " << fragment.width;

        if (!textBox->isLeftToRightDirection() || textBox->dirOverride()) {
            ts << (textBox->isLeftToRightDirection() ? " LTR" : " RTL");
            if (textBox->dirOverride())
                ts << " override";
        }

        ts << ": " << quoteAndEscapeNonPrintables(text.substring(fragment.characterOffset, fragment.length)) << "\n";
    }
}

static inline void updateFontInAllDescendants(RenderObject* start, SVGTextLayoutAttributesBuilder* builder = 0)
{
    for (RenderObject* descendant = start; descendant; descendant = descendant->nextInPreOrder(start)) {
        if (!descendant->isSVGInlineText())
            continue;
        RenderSVGInlineText* text = toRenderSVGInlineText(descendant);
        text->updateScaledFont();
        if (builder)
            builder->rebuildMetricsForTextRenderer(text);
    }
}

static inline FloatRect calculateFragmentBoundaries(const RenderSVGInlineText& textRenderer, const SVGTextFragment& fragment)
{
    float scalingFactor = textRenderer.scalingFactor();
    ASSERT(scalingFactor);
    float baseline = textRenderer.scaledFont().fontMetrics().floatAscent() / scalingFactor;

    AffineTransform fragmentTransform;
    FloatRect fragmentRect(fragment.x, fragment.y - baseline, fragment.width, fragment.height);
    fragment.buildFragmentTransform(fragmentTransform);
    return fragmentTransform.mapRect(fragmentRect);
}

static inline void processRenderSVGInlineText(const RenderSVGInlineText& text, unsigned& atCharacter, bool& lastCharacterWasSpace)
{
    if (text.style().whiteSpace() == PRE) {
        atCharacter += text.textLength();
        return;
    }

    for (unsigned textPosition = 0, textLength = text.textLength(); textPosition < textLength; ++textPosition) {
        const UChar currentCharacter = text[textPosition];
        if (currentCharacter == ' ' && lastCharacterWasSpace)
            continue;

        lastCharacterWasSpace = currentCharacter == ' ';
        ++atCharacter;
    }
}

void SVGTextLayoutEngine::layoutInlineTextBox(SVGInlineTextBox* textBox)
{
    ASSERT(textBox);

    RenderSVGInlineText* text = toRenderSVGInlineText(textBox->textRenderer());
    ASSERT(text);
    ASSERT(text->parent());
    ASSERT(text->parent()->node());
    ASSERT(text->parent()->node()->isSVGElement());

    const RenderStyle* style = text->style();
    ASSERT(style);

    textBox->clearTextFragments();
    m_isVerticalText = style->svgStyle()->isVerticalWritingMode();
    layoutTextOnLineOrPath(textBox, text, style);

    if (m_inPathLayout) {
        m_pathLayoutBoxes.append(textBox);
        return;
    }

    m_lineLayoutBoxes.append(textBox);
}

void write(TextStream& ts, const RenderSVGInlineText& text, int indent)
{
    writeIndent(ts, indent);
    ts << text.renderName();

    if (text.element()) {
        String tagName = getTagName(static_cast<SVGStyledElement*>(text.element()));
        if (!tagName.isEmpty())
            ts << " {" << tagName << "}";
    }

    ts << " at (" << text.xPos() << "," << text.yPos() << ") size " << text.width() << "x" << text.height() << "\n";
    writeSVGInlineText(ts, text, indent);
}