void SVGRootInlineBox::layoutCharactersInTextBoxes(InlineFlowBox* start, SVGTextLayoutEngine& characterLayout)
{
for (InlineBox* child = start->firstChild(); child; child = child->nextOnLine()) {
if (child->isSVGInlineTextBox()) {
ASSERT(child->renderer().isSVGInlineText());
SVGInlineTextBox* textBox = toSVGInlineTextBox(child);
characterLayout.layoutInlineTextBox(textBox);
} else {
// Skip generated content.
Node* node = child->renderer().node();
if (!node)
continue;
ASSERT_WITH_SECURITY_IMPLICATION(child->isInlineFlowBox());
SVGInlineFlowBox* flowBox = toSVGInlineFlowBox(child);
bool isTextPath = node->hasTagName(SVGNames::textPathTag);
if (isTextPath) {
// Build text chunks for all <textPath> children, using the line layout algorithm.
// This is needeed as text-anchor is just an additional startOffset for text paths.
SVGTextLayoutEngine lineLayout(characterLayout.layoutAttributes());
layoutCharactersInTextBoxes(flowBox, lineLayout);
characterLayout.beginTextPathLayout(&child->renderer(), lineLayout);
}
layoutCharactersInTextBoxes(flowBox, characterLayout);
if (isTextPath)
characterLayout.endTextPathLayout();
}
}
}
void SVGTextLayoutEngine::beginTextPathLayout(SVGInlineFlowBox* flowBox)
{
// Build text chunks for all <textPath> children, using the line layout algorithm.
// This is needeed as text-anchor is just an additional startOffset for text paths.
SVGTextLayoutEngine lineLayout(m_layoutAttributes);
lineLayout.m_textLengthSpacingInEffect = m_textLengthSpacingInEffect;
lineLayout.layoutCharactersInTextBoxes(flowBox);
m_inPathLayout = true;
LayoutSVGTextPath* textPath = &toLayoutSVGTextPath(flowBox->layoutObject());
Path path = textPath->layoutPath();
if (path.isEmpty())
return;
m_textPathCalculator = new Path::PositionCalculator(path);
m_textPathStartOffset = textPath->startOffset();
m_textPathLength = path.length();
if (m_textPathStartOffset > 0 && m_textPathStartOffset <= 1)
m_textPathStartOffset *= m_textPathLength;
SVGTextPathChunkBuilder textPathChunkLayoutBuilder;
textPathChunkLayoutBuilder.processTextChunks(lineLayout.m_lineLayoutBoxes);
m_textPathStartOffset += textPathChunkLayoutBuilder.totalTextAnchorShift();
m_textPathCurrentOffset = m_textPathStartOffset;
// Eventually handle textLength adjustments.
SVGLengthAdjustType lengthAdjust = SVGLengthAdjustUnknown;
float desiredTextLength = 0;
if (SVGTextContentElement* textContentElement = SVGTextContentElement::elementFromLayoutObject(textPath)) {
SVGLengthContext lengthContext(textContentElement);
lengthAdjust = textContentElement->lengthAdjust()->currentValue()->enumValue();
if (textContentElement->textLengthIsSpecifiedByUser())
desiredTextLength = textContentElement->textLength()->currentValue()->value(lengthContext);
else
desiredTextLength = 0;
}
if (!desiredTextLength)
return;
float totalLength = textPathChunkLayoutBuilder.totalLength();
if (lengthAdjust == SVGLengthAdjustSpacing)
m_textPathSpacing = (desiredTextLength - totalLength) / textPathChunkLayoutBuilder.totalCharacters();
else
m_textPathScaling = desiredTextLength / totalLength;
}
