TextRun SVGTextMetrics::constructTextRun(LineLayoutSVGInlineText textLayoutItem, unsigned position, unsigned length, TextDirection textDirection)
{
const ComputedStyle& style = textLayoutItem.styleRef();
TextRun run(static_cast<const LChar*>(nullptr) // characters, will be set below if non-zero.
, 0 // length, will be set below if non-zero.
, 0 // xPos, only relevant with allowTabs=true
, 0 // padding, only relevant for justified text, not relevant for SVG
, TextRun::AllowTrailingExpansion
, textDirection
, isOverride(style.unicodeBidi()) /* directionalOverride */);
if (length) {
if (textLayoutItem.is8Bit())
run.setText(textLayoutItem.characters8() + position, length);
else
run.setText(textLayoutItem.characters16() + position, length);
}
// We handle letter & word spacing ourselves.
run.disableSpacing();
// Propagate the maximum length of the characters buffer to the TextRun, even when we're only processing a substring.
run.setCharactersLength(textLayoutItem.textLength() - position);
ASSERT(run.charactersLength() >= run.length());
return run;
}
int SVGInlineTextBox::offsetForPositionInFragment(
const SVGTextFragment& fragment,
LayoutUnit position,
bool includePartialGlyphs) const {
LineLayoutSVGInlineText lineLayoutItem =
LineLayoutSVGInlineText(this->getLineLayoutItem());
float scalingFactor = lineLayoutItem.scalingFactor();
ASSERT(scalingFactor);
const ComputedStyle& style = lineLayoutItem.styleRef();
TextRun textRun = constructTextRun(style, fragment);
// Eventually handle lengthAdjust="spacingAndGlyphs".
// FIXME: Handle vertical text.
if (fragment.isTransformed()) {
AffineTransform fragmentTransform = fragment.buildFragmentTransform();
textRun.setHorizontalGlyphStretch(
clampTo<float>(fragmentTransform.xScale()));
}
return fragment.characterOffset - start() +
lineLayoutItem.scaledFont().offsetForPosition(
textRun, position * scalingFactor, includePartialGlyphs);
}
void SVGTextMetricsCalculator::setupBidiRuns()
{
const ComputedStyle& style = m_text.styleRef();
m_textDirection = style.direction();
if (isOverride(style.unicodeBidi()))
return;
BidiStatus status(LTR, false);
status.last = status.lastStrong = WTF::Unicode::OtherNeutral;
m_bidiResolver.setStatus(status);
m_bidiResolver.setPositionIgnoringNestedIsolates(TextRunIterator(&m_run, 0));
const bool hardLineBreak = false;
const bool reorderRuns = false;
m_bidiResolver.createBidiRunsForLine(TextRunIterator(&m_run, m_run.length()), NoVisualOverride, hardLineBreak, reorderRuns);
BidiRunList<BidiCharacterRun>& bidiRuns = m_bidiResolver.runs();
m_bidiRun = bidiRuns.firstRun();
}
void SVGTextLayoutEngine::layoutInlineTextBox(SVGInlineTextBox* textBox)
{
ASSERT(textBox);
LineLayoutSVGInlineText textLineLayout = LineLayoutSVGInlineText(textBox->lineLayoutItem());
ASSERT(textLineLayout.parent());
ASSERT(textLineLayout.parent().node());
ASSERT(textLineLayout.parent().node()->isSVGElement());
const ComputedStyle& style = textLineLayout.styleRef();
textBox->clearTextFragments();
m_isVerticalText = !style.isHorizontalWritingMode();
layoutTextOnLineOrPath(textBox, textLineLayout, style);
if (m_inPathLayout)
return;
m_lineLayoutBoxes.append(textBox);
}
void SVGTextChunkBuilder::handleTextChunk(BoxListConstIterator boxStart,
BoxListConstIterator boxEnd) {
ASSERT(*boxStart);
const LineLayoutSVGInlineText textLineLayout =
LineLayoutSVGInlineText((*boxStart)->getLineLayoutItem());
const ComputedStyle& style = textLineLayout.styleRef();
// Handle 'lengthAdjust' property.
float desiredTextLength = 0;
SVGLengthAdjustType lengthAdjust = SVGLengthAdjustUnknown;
if (SVGTextContentElement* textContentElement =
SVGTextContentElement::elementFromLineLayoutItem(
textLineLayout.parent())) {
lengthAdjust =
textContentElement->lengthAdjust()->currentValue()->enumValue();
SVGLengthContext lengthContext(textContentElement);
if (textContentElement->textLengthIsSpecifiedByUser())
desiredTextLength =
textContentElement->textLength()->currentValue()->value(
lengthContext);
else
desiredTextLength = 0;
}
bool processTextLength = desiredTextLength > 0;
bool processTextAnchor = needsTextAnchorAdjustment(style);
if (!processTextAnchor && !processTextLength)
return;
bool isVerticalText = !style.isHorizontalWritingMode();
// Calculate absolute length of whole text chunk (starting from text box
// 'start', spanning 'length' text boxes).
ChunkLengthAccumulator lengthAccumulator(isVerticalText);
lengthAccumulator.processRange(boxStart, boxEnd);
if (processTextLength) {
float chunkLength = lengthAccumulator.length();
if (lengthAdjust == SVGLengthAdjustSpacing) {
float textLengthShift =
(desiredTextLength - chunkLength) / lengthAccumulator.numCharacters();
unsigned atCharacter = 0;
for (auto boxIter = boxStart; boxIter != boxEnd; ++boxIter) {
Vector<SVGTextFragment>& fragments = (*boxIter)->textFragments();
if (fragments.isEmpty())
continue;
processTextLengthSpacingCorrection(isVerticalText, textLengthShift,
fragments, atCharacter);
}
// Fragments have been adjusted, we have to recalculate the chunk
// length, to be able to apply the text-anchor shift.
if (processTextAnchor) {
lengthAccumulator.reset();
lengthAccumulator.processRange(boxStart, boxEnd);
}
} else {
ASSERT(lengthAdjust == SVGLengthAdjustSpacingAndGlyphs);
float textLengthScale = desiredTextLength / chunkLength;
float textLengthBias = 0;
bool foundFirstFragment = false;
for (auto boxIter = boxStart; boxIter != boxEnd; ++boxIter) {
SVGInlineTextBox* textBox = *boxIter;
Vector<SVGTextFragment>& fragments = textBox->textFragments();
if (fragments.isEmpty())
continue;
if (!foundFirstFragment) {
foundFirstFragment = true;
textLengthBias =
computeTextLengthBias(fragments.first(), textLengthScale);
}
applyTextLengthScaleAdjustment(textLengthScale, textLengthBias,
fragments);
}
}
}
if (!processTextAnchor)
return;
float textAnchorShift =
calculateTextAnchorShift(style, lengthAccumulator.length());
for (auto boxIter = boxStart; boxIter != boxEnd; ++boxIter) {
Vector<SVGTextFragment>& fragments = (*boxIter)->textFragments();
if (fragments.isEmpty())
continue;
processTextAnchorCorrection(isVerticalText, textAnchorShift, fragments);
}
}
