GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const InlineTextBox* inlineTextBox)
{
ASSERT(!inlineTextBox || inlineTextBox->lineStyle() == lineStyle);
TextDecoration decoration = lineStyle.textDecorationsInEffect();
if (decoration == TextDecorationNone)
return GlyphOverflow();
float strokeThickness = textDecorationStrokeThickness(lineStyle.fontSize());
float controlPointDistance;
float step;
float wavyOffset;
TextDecorationStyle decorationStyle = lineStyle.textDecorationStyle();
float height = lineStyle.fontCascade().fontMetrics().floatHeight();
GlyphOverflow overflowResult;
if (decorationStyle == TextDecorationStyleWavy) {
getWavyStrokeParameters(strokeThickness, controlPointDistance, step);
wavyOffset = wavyOffsetFromDecoration();
overflowResult.left = strokeThickness;
overflowResult.right = strokeThickness;
}
// These metrics must match where underlines get drawn.
if (decoration & TextDecorationUnderline) {
// Compensate for the integral ceiling in GraphicsContext::computeLineBoundsAndAntialiasingModeForText()
int underlineOffset = 1;
underlineOffset += computeUnderlineOffset(lineStyle.textUnderlinePosition(), lineStyle.fontMetrics(), inlineTextBox, strokeThickness);
if (decorationStyle == TextDecorationStyleWavy) {
extendIntToFloat(overflowResult.bottom, underlineOffset + wavyOffset + controlPointDistance + strokeThickness - height);
extendIntToFloat(overflowResult.top, -(underlineOffset + wavyOffset - controlPointDistance - strokeThickness));
} else {
extendIntToFloat(overflowResult.bottom, underlineOffset + strokeThickness - height);
extendIntToFloat(overflowResult.top, -underlineOffset);
}
}
if (decoration & TextDecorationOverline) {
if (decorationStyle == TextDecorationStyleWavy) {
extendIntToFloat(overflowResult.bottom, -wavyOffset + controlPointDistance + strokeThickness - height);
extendIntToFloat(overflowResult.top, wavyOffset + controlPointDistance + strokeThickness);
} else {
extendIntToFloat(overflowResult.bottom, strokeThickness - height);
// top is untouched
}
}
if (decoration & TextDecorationLineThrough) {
float baseline = lineStyle.fontMetrics().floatAscent();
if (decorationStyle == TextDecorationStyleWavy) {
extendIntToFloat(overflowResult.bottom, 2 * baseline / 3 + controlPointDistance + strokeThickness - height);
extendIntToFloat(overflowResult.top, -(2 * baseline / 3 - controlPointDistance - strokeThickness));
} else {
extendIntToFloat(overflowResult.bottom, 2 * baseline / 3 + strokeThickness - height);
extendIntToFloat(overflowResult.top, -(2 * baseline / 3));
}
}
return overflowResult;
}
TextDecorationPainter::TextDecorationPainter(GraphicsContext& context, TextDecoration decoration, const RenderText& renderer, bool isFirstLine)
: m_context(context)
, m_decoration(decoration)
, m_wavyOffset(wavyOffsetFromDecoration())
, m_isPrinting(renderer.document().printing())
, m_styles(stylesForRenderer(renderer, m_decoration, isFirstLine))
, m_lineStyle(isFirstLine ? renderer.firstLineStyle() : renderer.style())
{
}
