SVGTextMetrics SVGTextMetricsCalculator::computeMetricsForCharacter(unsigned textPosition) { if (m_bidiRun) { if (textPosition >= static_cast<unsigned>(m_bidiRun->stop())) { m_bidiRun = m_bidiRun->next(); // New BiDi run means new reference position for measurements, so reset |m_totalWidth|. m_totalWidth = 0; } ASSERT(m_bidiRun); ASSERT(static_cast<int>(textPosition) < m_bidiRun->stop()); m_textDirection = m_bidiRun->direction(); } unsigned metricsLength = characterStartsSurrogatePair(textPosition) ? 2 : 1; SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(m_text, textPosition, metricsLength, m_textDirection); ASSERT(metrics.length() == metricsLength); unsigned startPosition = m_bidiRun ? m_bidiRun->start() : 0; ASSERT(startPosition <= textPosition); SVGTextMetrics complexStartToCurrentMetrics = SVGTextMetrics::measureCharacterRange(m_text, startPosition, textPosition - startPosition + metricsLength, m_textDirection); // Frequent case for Arabic text: when measuring a single character the arabic isolated form is taken // when laying out the glyph "in context" (with it's surrounding characters) it changes due to shaping. // So whenever currentWidth != currentMetrics.width(), we are processing a text run whose length is // not equal to the sum of the individual lengths of the glyphs, when measuring them isolated. float currentWidth = complexStartToCurrentMetrics.width() - m_totalWidth; if (currentWidth != metrics.width()) metrics.setWidth(currentWidth); m_totalWidth = complexStartToCurrentMetrics.width(); return metrics; }
SVGTextMetrics SVGTextMetricsCalculator::computeMetricsForCharacterComplex(unsigned textPosition) { unsigned metricsLength = characterStartsSurrogatePair(textPosition) ? 2 : 1; SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(m_text, textPosition, metricsLength, m_textDirection); ASSERT(metrics.length() == metricsLength); unsigned startPosition = m_bidiRun ? m_bidiRun->start() : 0; ASSERT(startPosition <= textPosition); SVGTextMetrics complexStartToCurrentMetrics = SVGTextMetrics::measureCharacterRange(m_text, startPosition, textPosition - startPosition + metricsLength, m_textDirection); // Frequent case for Arabic text: when measuring a single character the arabic isolated form is taken // when rendering the glyph "in context" (with it's surrounding characters) it changes due to shaping. // So whenever currentWidth != currentMetrics.width(), we are processing a text run whose length is // not equal to the sum of the individual lengths of the glyphs, when measuring them isolated. float currentWidth = complexStartToCurrentMetrics.width() - m_totalWidth; if (currentWidth != metrics.width()) metrics.setWidth(currentWidth); m_totalWidth = complexStartToCurrentMetrics.width(); return metrics; }
void SVGTextLayoutAttributesBuilder::propagateLayoutAttributes(RenderObject* start, Vector<SVGTextLayoutAttributes>& allAttributes, unsigned& atCharacter, UChar& lastCharacter) const { for (RenderObject* child = start->firstChild(); child; child = child->nextSibling()) { if (child->isSVGInlineText()) { RenderSVGInlineText* text = toRenderSVGInlineText(child); const UChar* characters = text->characters(); unsigned textLength = text->textLength(); bool preserveWhiteSpace = shouldPreserveAllWhiteSpace(text->style()); SVGTextLayoutAttributes attributes(text); attributes.reserveCapacity(textLength); unsigned valueListPosition = atCharacter; unsigned metricsLength = 1; SVGTextMetrics lastMetrics(SVGTextMetrics::SkippedSpaceMetrics); for (unsigned textPosition = 0; textPosition < textLength; textPosition += metricsLength) { const UChar& currentCharacter = characters[textPosition]; SVGTextMetrics startToCurrentMetrics; SVGTextMetrics currentMetrics; unsigned valueListAdvance = 0; if (U16_IS_LEAD(currentCharacter) && (textPosition + 1) < textLength && U16_IS_TRAIL(characters[textPosition + 1])) { // Handle surrogate pairs. startToCurrentMetrics = SVGTextMetrics::measureCharacterRange(text, 0, textPosition + 2); currentMetrics = SVGTextMetrics::measureCharacterRange(text, textPosition, 2); metricsLength = currentMetrics.length(); valueListAdvance = 1; } else { // Handle BMP characters. startToCurrentMetrics = SVGTextMetrics::measureCharacterRange(text, 0, textPosition + 1); currentMetrics = SVGTextMetrics::measureCharacterRange(text, textPosition, 1); metricsLength = currentMetrics.length(); valueListAdvance = metricsLength; } if (!metricsLength) break; // Frequent case for Arabic text: when measuring a single character the arabic isolated form is taken // when rendering the glyph "in context" (with it's surrounding characters) it changes due to shaping. // So whenever runWidthAdvance != currentMetrics.width(), we are processing a text run whose length is // not equal to the sum of the individual lengths of the glyphs, when measuring them isolated. float runWidthAdvance = startToCurrentMetrics.width() - lastMetrics.width(); if (runWidthAdvance != currentMetrics.width()) currentMetrics.setWidth(runWidthAdvance); lastMetrics = startToCurrentMetrics; if (!preserveWhiteSpace && characterIsSpace(currentCharacter) && characterIsSpaceOrNull(lastCharacter)) { attributes.positioningLists().appendEmptyValues(); attributes.textMetricsValues().append(SVGTextMetrics(SVGTextMetrics::SkippedSpaceMetrics)); continue; } SVGTextLayoutAttributes::PositioningLists& positioningLists = attributes.positioningLists(); positioningLists.appendValuesFromPosition(m_positioningLists, valueListPosition); attributes.textMetricsValues().append(currentMetrics); // Pad x/y/dx/dy/rotate value lists with empty values, if the metrics span more than one character. if (metricsLength > 1) { for (unsigned i = 0; i < metricsLength - 1; ++i) positioningLists.appendEmptyValues(); } lastCharacter = currentCharacter; valueListPosition += valueListAdvance; } #if DUMP_TEXT_LAYOUT_ATTRIBUTES > 0 fprintf(stderr, "\nDumping layout attributes for RenderSVGInlineText, renderer=%p, node=%p (atCharacter: %i)\n", text, text->node(), atCharacter); fprintf(stderr, "BiDi properties: unicode-bidi=%i, block direction=%i\n", text->style()->unicodeBidi(), text->style()->direction()); attributes.dump(); #endif text->storeLayoutAttributes(attributes); allAttributes.append(attributes); atCharacter = valueListPosition; continue; } if (!child->isSVGInline()) continue; propagateLayoutAttributes(child, allAttributes, atCharacter, lastCharacter); } }