EAlignmentBaseline SVGTextLayoutEngineBaseline::dominantBaselineToAlignmentBaseline(bool isVerticalText, const LayoutObject* textLayoutObject) const
{
ASSERT(textLayoutObject);
ASSERT(textLayoutObject->style());
const SVGComputedStyle& style = textLayoutObject->style()->svgStyle();
EDominantBaseline baseline = style.dominantBaseline();
if (baseline == DB_AUTO) {
if (isVerticalText)
baseline = DB_CENTRAL;
else
baseline = DB_ALPHABETIC;
}
switch (baseline) {
case DB_USE_SCRIPT:
// TODO(fs): The dominant-baseline and the baseline-table components
// are set by determining the predominant script of the character data
// content.
return AB_ALPHABETIC;
case DB_NO_CHANGE:
ASSERT(textLayoutObject->parent());
return dominantBaselineToAlignmentBaseline(isVerticalText, textLayoutObject->parent());
case DB_RESET_SIZE:
ASSERT(textLayoutObject->parent());
return dominantBaselineToAlignmentBaseline(isVerticalText, textLayoutObject->parent());
case DB_IDEOGRAPHIC:
return AB_IDEOGRAPHIC;
case DB_ALPHABETIC:
return AB_ALPHABETIC;
case DB_HANGING:
return AB_HANGING;
case DB_MATHEMATICAL:
return AB_MATHEMATICAL;
case DB_CENTRAL:
return AB_CENTRAL;
case DB_MIDDLE:
return AB_MIDDLE;
case DB_TEXT_AFTER_EDGE:
return AB_TEXT_AFTER_EDGE;
case DB_TEXT_BEFORE_EDGE:
return AB_TEXT_BEFORE_EDGE;
default:
ASSERT_NOT_REACHED();
return AB_AUTO;
}
}
float SVGTextLayoutEngineBaseline::calculateAlignmentBaselineShift(bool isVerticalText, const RenderObject* textRenderer) const
{
ASSERT(textRenderer);
ASSERT(textRenderer->style());
ASSERT(textRenderer->style()->svgStyle());
ASSERT(textRenderer->parent());
const RenderObject* textRendererParent = textRenderer->parent();
ASSERT(textRendererParent);
EAlignmentBaseline baseline = textRenderer->style()->svgStyle()->alignmentBaseline();
if (baseline == AB_AUTO) {
baseline = dominantBaselineToAlignmentBaseline(isVerticalText, textRendererParent);
ASSERT(baseline != AB_AUTO);
}
const FontMetrics& fontMetrics = m_font.fontMetrics();
// Note: http://wiki.apache.org/xmlgraphics-fop/LineLayout/AlignmentHandling
switch (baseline) {
case AB_BASELINE:
return dominantBaselineToAlignmentBaseline(isVerticalText, textRendererParent);
case AB_BEFORE_EDGE:
case AB_TEXT_BEFORE_EDGE:
return fontMetrics.floatAscent();
case AB_MIDDLE:
return fontMetrics.xHeight() / 2;
case AB_CENTRAL:
return (fontMetrics.floatAscent() - fontMetrics.floatDescent()) / 2;
case AB_AFTER_EDGE:
case AB_TEXT_AFTER_EDGE:
case AB_IDEOGRAPHIC:
return fontMetrics.floatDescent();
case AB_ALPHABETIC:
return 0;
case AB_HANGING:
return fontMetrics.floatAscent() * 8 / 10.f;
case AB_MATHEMATICAL:
return fontMetrics.floatAscent() / 2;
default:
ASSERT_NOT_REACHED();
return 0;
}
}
float SVGTextLayoutEngineBaseline::calculateAlignmentBaselineShift(bool isVerticalText, const LayoutObject* textLayoutObject) const
{
ASSERT(textLayoutObject);
ASSERT(textLayoutObject->style());
ASSERT(textLayoutObject->parent());
const LayoutObject* textLayoutObjectParent = textLayoutObject->parent();
ASSERT(textLayoutObjectParent);
EAlignmentBaseline baseline = textLayoutObject->style()->svgStyle().alignmentBaseline();
if (baseline == AB_AUTO || baseline == AB_BASELINE) {
baseline = dominantBaselineToAlignmentBaseline(isVerticalText, textLayoutObjectParent);
ASSERT(baseline != AB_AUTO && baseline != AB_BASELINE);
}
const FontMetrics& fontMetrics = m_font.fontMetrics();
float ascent = fontMetrics.floatAscent() / m_effectiveZoom;
float descent = fontMetrics.floatDescent() / m_effectiveZoom;
float xheight = fontMetrics.xHeight() / m_effectiveZoom;
// Note: http://wiki.apache.org/xmlgraphics-fop/LineLayout/AlignmentHandling
switch (baseline) {
case AB_BEFORE_EDGE:
case AB_TEXT_BEFORE_EDGE:
return ascent;
case AB_MIDDLE:
return xheight / 2;
case AB_CENTRAL:
return (ascent - descent) / 2;
case AB_AFTER_EDGE:
case AB_TEXT_AFTER_EDGE:
case AB_IDEOGRAPHIC:
return -descent;
case AB_ALPHABETIC:
return 0;
case AB_HANGING:
return ascent * 8 / 10.f;
case AB_MATHEMATICAL:
return ascent / 2;
case AB_BASELINE:
default:
ASSERT_NOT_REACHED();
return 0;
}
}
