C++ TextRun::is8Bit方法代码示例

static void normalizeCharacters(const TextRun& run, unsigned length, UChar* destination, unsigned* destinationLength)
{
    unsigned position = 0;
    bool error = false;
    const UChar* source;
    String stringFor8BitRun;
    if (run.is8Bit()) {
        stringFor8BitRun = String::make16BitFrom8BitSource(run.characters8(), run.length());
        source = stringFor8BitRun.characters16();
    } else {
        source = run.characters16();
    }

    *destinationLength = 0;
    while (position < length) {
        UChar32 character;
        U16_NEXT(source, position, length, character);
        // Don't normalize tabs as they are not treated as spaces for word-end.
        if (run.normalizeSpace() && Character::isNormalizedCanvasSpaceCharacter(character))
            character = spaceCharacter;
        else if (Character::treatAsSpace(character) && character != noBreakSpaceCharacter)
            character = spaceCharacter;
        else if (Character::treatAsZeroWidthSpaceInComplexScript(character))
            character = zeroWidthSpaceCharacter;

        U16_APPEND(destination, *destinationLength, length, character, error);
        ASSERT_UNUSED(error, !error);
    }
}

void LayoutSVGInlineText::updateMetricsList(bool& lastCharacterWasWhiteSpace)
{
    m_metrics.clear();

    if (!textLength())
        return;

    TextRun run = constructTextRun(*this, 0, textLength(), styleRef().direction());
    BidiResolver<TextRunIterator, BidiCharacterRun> bidiResolver;
    BidiRunList<BidiCharacterRun>& bidiRuns = bidiResolver.runs();
    bool bidiOverride = isOverride(styleRef().unicodeBidi());
    BidiStatus status(LTR, bidiOverride);
    if (run.is8Bit() || bidiOverride) {
        WTF::Unicode::CharDirection direction = WTF::Unicode::LeftToRight;
        // If BiDi override is in effect, use the specified direction.
        if (bidiOverride && !styleRef().isLeftToRightDirection())
            direction = WTF::Unicode::RightToLeft;
        bidiRuns.addRun(new BidiCharacterRun(0, run.charactersLength(), status.context.get(), direction));
    } else {
        status.last = status.lastStrong = WTF::Unicode::OtherNeutral;
        bidiResolver.setStatus(status);
        bidiResolver.setPositionIgnoringNestedIsolates(TextRunIterator(&run, 0));
        const bool hardLineBreak = false;
        const bool reorderRuns = false;
        bidiResolver.createBidiRunsForLine(TextRunIterator(&run, run.length()), NoVisualOverride, hardLineBreak, reorderRuns);
    }

    for (const BidiCharacterRun* bidiRun = bidiRuns.firstRun(); bidiRun; bidiRun = bidiRun->next()) {
        TextRun subRun = constructTextRun(*this, bidiRun->start(), bidiRun->stop() - bidiRun->start(),
            bidiRun->direction());
        addMetricsFromRun(subRun, lastCharacterWasWhiteSpace);
    }

    bidiResolver.runs().deleteRuns();
}

Font::CodePath Font::codePath(const TextRun& run) const
{
    if (s_codePath != Auto)
        return s_codePath;

#if ENABLE(SVG_FONTS)
    if (run.renderingContext())
        return Simple;
#endif

    if (m_fontDescription.featureSettings() && m_fontDescription.featureSettings()->size() > 0)
        return Complex;
    
    if (run.length() > 1 && !WidthIterator::supportsTypesettingFeatures(*this))
        return Complex;

    if (!run.characterScanForCodePath())
        return Simple;

    if (run.is8Bit())
        return Simple;

    // Start from 0 since drawing and highlighting also measure the characters before run->from.
    return characterRangeCodePath(run.characters16(), run.length());
}

UniscribeHelperTextRun::UniscribeHelperTextRun(const TextRun& run,
                                               const Font& font)
    : UniscribeHelper(0, run.length(), run.rtl(),
                      font.primaryFont()->platformData().hfont(),
                      font.primaryFont()->platformData().scriptCache(),
                      font.primaryFont()->platformData().scriptFontProperties(),
                      font.primaryFont()->spaceGlyph())
    , m_font(&font)
    , m_fontIndex(0)
{
    if (run.is8Bit()) {
        m_stringFor8BitRun = String::make16BitFrom8BitSource(run.characters8(), run.length());
        setInput(m_stringFor8BitRun.characters16());
    } else {
        setInput(run.characters16());
    }

    setDirectionalOverride(run.directionalOverride());
    setLetterSpacing(font.letterSpacing());
    setSpaceWidth(font.spaceWidth());
    setWordSpacing(font.wordSpacing());
    setAscent(font.fontMetrics().ascent());
    setRangeProperties(font.fontDescription().featureSettings());

    init();

    // Expansion is the amount to add to make justification happen. This
    // should be done after Init() so all the runs are already measured.
    if (run.expansion() > 0)
        justify(run.expansion());
}

static void normalizeCharacters(const TextRun& run, UChar* destination, int length)
{
    int position = 0;
    bool error = false;
    const UChar* source;
    String stringFor8BitRun;
    if (run.is8Bit()) {
        stringFor8BitRun = String::make16BitFrom8BitSource(run.characters8(), run.length());
        source = stringFor8BitRun.characters16();
    } else
        source = run.characters16();

    while (position < length) {
        UChar32 character;
        int nextPosition = position;
        U16_NEXT(source, nextPosition, length, character);
        // Don't normalize tabs as they are not treated as spaces for word-end.
        if (Font::treatAsSpace(character) && character != '\t')
            character = ' ';
        else if (Font::treatAsZeroWidthSpaceInComplexScript(character))
            character = zeroWidthSpace;
        U16_APPEND(destination, position, length, character, error);
        ASSERT_UNUSED(error, !error);
        position = nextPosition;
    }
}

bool ShapeResultSpacing::isFirstRun(const TextRun& run) const
{
    if (&run == &m_textRun)
        return true;
    return run.is8Bit()
        ? run.characters8() == m_textRun.characters8()
        : run.characters16() == m_textRun.characters16();
}

void computeNormalizedSpaces(const TextRun& run, bool mirror, String& normalizedSpacesStringCache)
{
    if (normalizedSpacesStringCache.length() == static_cast<unsigned>(run.charactersLength()))
        return;
    if (run.is8Bit())
        normalizedSpacesStringCache = Font::normalizeSpaces(run.characters8(), run.charactersLength());
    else
        normalizedSpacesStringCache = Font::normalizeSpaces(run.characters16(), run.charactersLength());
    if (mirror)
        normalizedSpacesStringCache = createStringWithMirroredCharacters(normalizedSpacesStringCache);
}

float ShapeResultSpacing::computeSpacing(const TextRun& run,
        size_t index,
        float& offset) {
    UChar32 character = run[index];
    bool treatAsSpace =
        (Character::treatAsSpace(character) ||
         (m_normalizeSpace &&
          Character::isNormalizedCanvasSpaceCharacter(character))) &&
        (character != '\t' || !m_allowTabs);
    if (treatAsSpace && character != noBreakSpaceCharacter)
        character = spaceCharacter;

    float spacing = 0;
    if (m_letterSpacing && !Character::treatAsZeroWidthSpace(character))
        spacing += m_letterSpacing;

    if (treatAsSpace &&
            (index || !isFirstRun(run) || character == noBreakSpaceCharacter))
        spacing += m_wordSpacing;

    if (!hasExpansion())
        return spacing;

    if (treatAsSpace)
        return spacing + nextExpansion();

    if (run.is8Bit() || m_textJustify != TextJustify::TextJustifyAuto)
        return spacing;

    // isCJKIdeographOrSymbol() has expansion opportunities both before and
    // after each character.
    // http://www.w3.org/TR/jlreq/#line_adjustment
    if (U16_IS_LEAD(character) && index + 1 < run.length() &&
            U16_IS_TRAIL(run[index + 1]))
        character = U16_GET_SUPPLEMENTARY(character, run[index + 1]);
    if (!Character::isCJKIdeographOrSymbol(character)) {
        m_isAfterExpansion = false;
        return spacing;
    }

    if (!m_isAfterExpansion) {
        // Take the expansion opportunity before this ideograph.
        float expandBefore = nextExpansion();
        if (expandBefore) {
            offset += expandBefore;
            spacing += expandBefore;
        }
        if (!hasExpansion())
            return spacing;
    }

    return spacing + nextExpansion();
}

TextDirection directionForRun(TextRun& run, bool* hasStrongDirectionality)
{
    if (!hasStrongDirectionality) {
        // 8bit is Latin-1 and therefore is always LTR.
        if (run.is8Bit())
            return LTR;

        // length == 1 for more than 90% of cases of width() for CJK text.
        if (run.length() == 1 && U16_IS_SINGLE(run.characters16()[0]))
            return directionForCharacter(run.characters16()[0]);
    }

    BidiResolver<TextRunIterator, BidiCharacterRun> bidiResolver;
    bidiResolver.setStatus(BidiStatus(run.direction(), run.directionalOverride()));
    bidiResolver.setPositionIgnoringNestedIsolates(TextRunIterator(&run, 0));
    return bidiResolver.determineParagraphDirectionality(hasStrongDirectionality);
}

SVGTextMetrics::SVGTextMetrics(RenderSVGInlineText* textRenderer, const TextRun& run)
{
    ASSERT(textRenderer);

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

    const Font& scaledFont = textRenderer->scaledFont();
    int length = 0;

    // Calculate width/height using the scaled font, divide this result by the scalingFactor afterwards.
    m_width = scaledFont.width(run, length, m_glyph.name) / scalingFactor;
    m_height = scaledFont.fontMetrics().floatHeight() / scalingFactor;

    m_glyph.unicodeString = run.is8Bit() ? String(run.characters8(), length) : String(run.characters16(), length);
    m_glyph.isValid = true;

    ASSERT(length >= 0);
    m_length = static_cast<unsigned>(length);
}

float ShapeResult::fillGlyphBufferForTextEmphasisRun(GlyphBuffer* glyphBuffer,
    const RunInfo* run, const TextRun& textRun, const GlyphData* emphasisData,
    float initialAdvance, unsigned from, unsigned to, unsigned runOffset)
{
    if (!run)
        return 0;

    unsigned graphemesInCluster = 1;
    float clusterAdvance = 0;

    FloatPoint glyphCenter = emphasisData->fontData->
        boundsForGlyph(emphasisData->glyph).center();

    TextDirection direction = textRun.direction();

    // A "cluster" in this context means a cluster as it is used by HarfBuzz:
    // The minimal group of characters and corresponding glyphs, that cannot be broken
    // down further from a text shaping point of view.
    // A cluster can contain multiple glyphs and grapheme clusters, with mutually
    // overlapping boundaries. Below we count grapheme clusters per HarfBuzz clusters,
    // then linearly split the sum of corresponding glyph advances by the number of
    // grapheme clusters in order to find positions for emphasis mark drawing.
    uint16_t clusterStart = direction == RTL
        ? run->m_startIndex + run->m_numCharacters + runOffset
        : run->glyphToCharacterIndex(0) + runOffset;

    float advanceSoFar = initialAdvance;
    unsigned numGlyphs = run->m_numGlyphs;
    for (unsigned i = 0; i < numGlyphs; ++i) {
        const HarfBuzzRunGlyphData& glyphData = run->m_glyphData[i];
        uint16_t currentCharacterIndex = run->m_startIndex + glyphData.characterIndex + runOffset;
        bool isRunEnd = (i + 1 == numGlyphs);
        bool isClusterEnd =  isRunEnd || (run->glyphToCharacterIndex(i + 1) + runOffset != currentCharacterIndex);

        if ((direction == RTL && currentCharacterIndex >= to) || (direction != RTL && currentCharacterIndex < from)) {
            advanceSoFar += glyphData.advance;
            direction == RTL ? --clusterStart : ++clusterStart;
            continue;
        }

        clusterAdvance += glyphData.advance;

        if (textRun.is8Bit()) {
            float glyphAdvanceX = glyphData.advance;
            if (Character::canReceiveTextEmphasis(textRun[currentCharacterIndex])) {
                addEmphasisMark(glyphBuffer, emphasisData, glyphCenter, advanceSoFar + glyphAdvanceX / 2);
            }
            advanceSoFar += glyphAdvanceX;
        } else if (isClusterEnd) {
            uint16_t clusterEnd;
            if (direction == RTL)
                clusterEnd = currentCharacterIndex;
            else
                clusterEnd = isRunEnd ? run->m_startIndex + run->m_numCharacters + runOffset : run->glyphToCharacterIndex(i + 1) + runOffset;

            graphemesInCluster = countGraphemesInCluster(textRun.characters16(), textRun.charactersLength(), clusterStart, clusterEnd);
            if (!graphemesInCluster || !clusterAdvance)
                continue;

            float glyphAdvanceX = clusterAdvance / graphemesInCluster;
            for (unsigned j = 0; j < graphemesInCluster; ++j) {
                // Do not put emphasis marks on space, separator, and control characters.
                if (Character::canReceiveTextEmphasis(textRun[currentCharacterIndex]))
                    addEmphasisMark(glyphBuffer, emphasisData, glyphCenter, advanceSoFar + glyphAdvanceX / 2);
                advanceSoFar += glyphAdvanceX;
            }
            clusterStart = clusterEnd;
            clusterAdvance = 0;
        }
    }
    return advanceSoFar - initialAdvance;
}