RenderCombineText.cpp [plain text]
#include "config.h"
#include "RenderCombineText.h"
#include "RenderBlock.h"
#include "StyleInheritedData.h"
#include <wtf/IsoMallocInlines.h>
#include <wtf/NeverDestroyed.h>
namespace WebCore {
WTF_MAKE_ISO_ALLOCATED_IMPL(RenderCombineText);
const float textCombineMargin = 1.15f;
RenderCombineText::RenderCombineText(Text& textNode, const String& string)
: RenderText(textNode, string)
, m_isCombined(false)
, m_needsFontUpdate(false)
{
}
void RenderCombineText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
if (!oldStyle || oldStyle->fontCascade() != style().fontCascade())
m_combineFontStyle = RenderStyle::clonePtr(style());
RenderText::styleDidChange(diff, oldStyle);
if (m_isCombined && selfNeedsLayout()) {
RenderText::setRenderedText(originalText()); m_isCombined = false;
}
m_needsFontUpdate = true;
combineTextIfNeeded();
}
void RenderCombineText::setRenderedText(const String& text)
{
RenderText::setRenderedText(text);
m_needsFontUpdate = true;
combineTextIfNeeded();
}
float RenderCombineText::width(unsigned from, unsigned length, const FontCascade& font, float xPosition, HashSet<const Font*>* fallbackFonts, GlyphOverflow* glyphOverflow) const
{
if (m_isCombined)
return !length ? 0 : font.size();
return RenderText::width(from, length, font, xPosition, fallbackFonts, glyphOverflow);
}
Optional<FloatPoint> RenderCombineText::computeTextOrigin(const FloatRect& boxRect) const
{
if (!m_isCombined)
return WTF::nullopt;
FloatPoint result = boxRect.minXMaxYCorner();
FloatSize combinedTextSize(m_combinedTextWidth, m_combinedTextAscent + m_combinedTextDescent);
result.move((boxRect.size().transposedSize() - combinedTextSize) / 2);
result.move(0, m_combinedTextAscent);
return result;
}
String RenderCombineText::combinedStringForRendering() const
{
if (m_isCombined) {
auto originalText = this->originalText();
ASSERT(!originalText.isNull());
return originalText;
}
return { };
}
void RenderCombineText::combineTextIfNeeded()
{
if (!m_needsFontUpdate)
return;
if (m_isCombined)
RenderText::setRenderedText(originalText());
m_isCombined = false;
m_needsFontUpdate = false;
if (style().isHorizontalWritingMode())
return;
auto description = originalFont().fontDescription();
float emWidth = description.computedSize() * textCombineMargin;
bool shouldUpdateFont = false;
FontSelector* fontSelector = style().fontCascade().fontSelector();
description.setOrientation(FontOrientation::Horizontal);
FontCascade horizontalFont(FontCascadeDescription { description }, style().fontCascade().letterSpacing(), style().fontCascade().wordSpacing());
horizontalFont.update(fontSelector);
GlyphOverflow glyphOverflow;
glyphOverflow.computeBounds = true;
float combinedTextWidth = width(0, text().length(), horizontalFont, 0, nullptr, &glyphOverflow);
float bestFitDelta = combinedTextWidth - emWidth;
auto bestFitDescription = description;
m_isCombined = combinedTextWidth <= emWidth;
if (m_isCombined)
shouldUpdateFont = m_combineFontStyle->setFontDescription(WTFMove(description)); else {
static const FontWidthVariant widthVariants[] = { FontWidthVariant::HalfWidth, FontWidthVariant::ThirdWidth, FontWidthVariant::QuarterWidth };
for (auto widthVariant : widthVariants) {
description.setWidthVariant(widthVariant);
FontCascade compressedFont(FontCascadeDescription { description }, style().fontCascade().letterSpacing(), style().fontCascade().wordSpacing());
compressedFont.update(fontSelector);
glyphOverflow.left = glyphOverflow.top = glyphOverflow.right = glyphOverflow.bottom = 0;
float runWidth = RenderText::width(0, text().length(), compressedFont, 0, nullptr, &glyphOverflow);
if (runWidth <= emWidth) {
combinedTextWidth = runWidth;
m_isCombined = true;
shouldUpdateFont = m_combineFontStyle->setFontDescription(WTFMove(description));
break;
}
float widthDelta = runWidth - emWidth;
if (widthDelta < bestFitDelta) {
bestFitDelta = widthDelta;
bestFitDescription = description;
}
}
}
if (!m_isCombined) {
float scaleFactor = std::max(0.4f, emWidth / (emWidth + bestFitDelta));
float originalSize = bestFitDescription.computedSize();
do {
float computedSize = originalSize * scaleFactor;
bestFitDescription.setComputedSize(computedSize);
shouldUpdateFont = m_combineFontStyle->setFontDescription(FontCascadeDescription { bestFitDescription });
FontCascade compressedFont(WTFMove(bestFitDescription), style().fontCascade().letterSpacing(), style().fontCascade().wordSpacing());
compressedFont.update(fontSelector);
glyphOverflow.left = glyphOverflow.top = glyphOverflow.right = glyphOverflow.bottom = 0;
float runWidth = RenderText::width(0, text().length(), compressedFont, 0, nullptr, &glyphOverflow);
if (runWidth <= emWidth) {
combinedTextWidth = runWidth;
m_isCombined = true;
break;
}
scaleFactor -= 0.05f;
} while (scaleFactor >= 0.4f);
}
if (shouldUpdateFont)
m_combineFontStyle->fontCascade().update(fontSelector);
if (m_isCombined) {
static NeverDestroyed<String> objectReplacementCharacterString(&objectReplacementCharacter, 1);
RenderText::setRenderedText(objectReplacementCharacterString.get());
m_combinedTextWidth = combinedTextWidth;
m_combinedTextAscent = glyphOverflow.top;
m_combinedTextDescent = glyphOverflow.bottom;
m_lineBoxes.dirtyRange(*this, 0, originalText().length(), originalText().length());
setNeedsLayout();
}
}
}