CSSSegmentedFontFace* FontFaceCache::get(const FontDescription& fontDescription, const AtomicString& family)
{
TraitsMap* familyFontFaces = m_fontFaces.get(family);
if (!familyFontFaces || familyFontFaces->isEmpty())
return 0;
FamilyToTraitsMap::AddResult traitsResult = m_fonts.add(family, nullptr);
if (!traitsResult.storedValue->value)
traitsResult.storedValue->value = adoptPtr(new TraitsMap);
FontTraits traits = fontDescription.traits();
TraitsMap::AddResult faceResult = traitsResult.storedValue->value->add(traits.bitfield(), nullptr);
if (!faceResult.storedValue->value) {
for (TraitsMap::const_iterator i = familyFontFaces->begin(); i != familyFontFaces->end(); ++i) {
CSSSegmentedFontFace* candidate = i->value.get();
FontTraits candidateTraits = candidate->traits();
if (traits.style() == FontStyleNormal && candidateTraits.style() != FontStyleNormal)
continue;
if (traits.variant() == FontVariantNormal && candidateTraits.variant() != FontVariantNormal)
continue;
if (!faceResult.storedValue->value || compareFontFaces(candidate, faceResult.storedValue->value.get(), traits))
faceResult.storedValue->value = candidate;
}
}
return faceResult.storedValue->value.get();
}
void FontDescription::setTraits(FontTraits traits)
{
setStyle(traits.style());
setVariant(traits.variant());
setWeight(traits.weight());
setStretch(traits.stretch());
}
PassRefPtr<FontData> CSSSegmentedFontFace::getFontData(const FontDescription& fontDescription)
{
if (!isValid())
return nullptr;
FontTraits desiredTraits = fontDescription.traits();
AtomicString emptyFontFamily = "";
FontCacheKey key = fontDescription.cacheKey(emptyFontFamily, desiredTraits);
RefPtr<SegmentedFontData>& fontData = m_fontDataTable.add(key.hash(), nullptr).storedValue->value;
if (fontData && fontData->numRanges())
return fontData; // No release, we have a reference to an object in the cache which should retain the ref count it has.
if (!fontData)
fontData = SegmentedFontData::create();
FontDescription requestedFontDescription(fontDescription);
requestedFontDescription.setTraits(m_traits);
requestedFontDescription.setSyntheticBold(m_traits.weight() < FontWeight600 && desiredTraits.weight() >= FontWeight600);
requestedFontDescription.setSyntheticItalic(m_traits.style() == FontStyleNormal && desiredTraits.style() == FontStyleItalic);
for (FontFaceList::reverse_iterator it = m_fontFaces.rbegin(); it != m_fontFaces.rend(); ++it) {
if (!(*it)->cssFontFace()->isValid())
continue;
if (RefPtr<SimpleFontData> faceFontData = (*it)->cssFontFace()->getFontData(requestedFontDescription)) {
ASSERT(!faceFontData->isSegmented());
#if ENABLE(SVG_FONTS)
// For SVG Fonts that specify that they only support the "normal" variant, we will assume they are incapable
// of small-caps synthesis and just ignore the font face.
if (faceFontData->isSVGFont() && desiredTraits.variant() == FontVariantSmallCaps && m_traits.variant() == FontVariantNormal)
continue;
#endif
appendFontData(fontData.get(), faceFontData.release(), (*it)->cssFontFace()->ranges());
}
}
if (fontData->numRanges())
return fontData; // No release, we have a reference to an object in the cache which should retain the ref count it has.
return nullptr;
}
static inline bool compareFontFaces(CSSSegmentedFontFace* first, CSSSegmentedFontFace* second, FontTraits desiredTraits)
{
const FontTraits& firstTraits = first->traits();
const FontTraits& secondTraits = second->traits();
bool firstHasDesiredVariant = firstTraits.variant() == desiredTraits.variant();
bool secondHasDesiredVariant = secondTraits.variant() == desiredTraits.variant();
if (firstHasDesiredVariant != secondHasDesiredVariant)
return firstHasDesiredVariant;
// We need to check font-variant css property for CSS2.1 compatibility.
if (desiredTraits.variant() == FontVariantSmallCaps) {
// Prefer a font that has indicated that it can only support small-caps to a font that claims to support
// all variants. The specialized font is more likely to be true small-caps and not require synthesis.
bool firstRequiresSmallCaps = firstTraits.variant() == FontVariantSmallCaps;
bool secondRequiresSmallCaps = secondTraits.variant() == FontVariantSmallCaps;
if (firstRequiresSmallCaps != secondRequiresSmallCaps)
return firstRequiresSmallCaps;
}
bool firstHasDesiredStyle = firstTraits.style() == desiredTraits.style();
bool secondHasDesiredStyle = secondTraits.style() == desiredTraits.style();
if (firstHasDesiredStyle != secondHasDesiredStyle)
return firstHasDesiredStyle;
if (desiredTraits.style() == FontStyleItalic) {
// Prefer a font that has indicated that it can only support italics to a font that claims to support
// all styles. The specialized font is more likely to be the one the author wants used.
bool firstRequiresItalics = firstTraits.style() == FontStyleItalic;
bool secondRequiresItalics = secondTraits.style() == FontStyleItalic;
if (firstRequiresItalics != secondRequiresItalics)
return firstRequiresItalics;
}
if (secondTraits.weight() == desiredTraits.weight())
return false;
if (firstTraits.weight() == desiredTraits.weight())
return true;
// http://www.w3.org/TR/2011/WD-css3-fonts-20111004/#font-matching-algorithm says :
// - If the desired weight is less than 400, weights below the desired weight are checked in descending order followed by weights above the desired weight in ascending order until a match is found.
// - If the desired weight is greater than 500, weights above the desired weight are checked in ascending order followed by weights below the desired weight in descending order until a match is found.
// - If the desired weight is 400, 500 is checked first and then the rule for desired weights less than 400 is used.
// - If the desired weight is 500, 400 is checked first and then the rule for desired weights less than 400 is used.
static const unsigned fallbackRuleSets = 9;
static const unsigned rulesPerSet = 8;
static const FontWeight weightFallbackRuleSets[fallbackRuleSets][rulesPerSet] = {
{ FontWeight200, FontWeight300, FontWeight400, FontWeight500, FontWeight600, FontWeight700, FontWeight800, FontWeight900 },
{ FontWeight100, FontWeight300, FontWeight400, FontWeight500, FontWeight600, FontWeight700, FontWeight800, FontWeight900 },
{ FontWeight200, FontWeight100, FontWeight400, FontWeight500, FontWeight600, FontWeight700, FontWeight800, FontWeight900 },
{ FontWeight500, FontWeight300, FontWeight200, FontWeight100, FontWeight600, FontWeight700, FontWeight800, FontWeight900 },
{ FontWeight400, FontWeight300, FontWeight200, FontWeight100, FontWeight600, FontWeight700, FontWeight800, FontWeight900 },
{ FontWeight700, FontWeight800, FontWeight900, FontWeight500, FontWeight400, FontWeight300, FontWeight200, FontWeight100 },
{ FontWeight800, FontWeight900, FontWeight600, FontWeight500, FontWeight400, FontWeight300, FontWeight200, FontWeight100 },
{ FontWeight900, FontWeight700, FontWeight600, FontWeight500, FontWeight400, FontWeight300, FontWeight200, FontWeight100 },
{ FontWeight800, FontWeight700, FontWeight600, FontWeight500, FontWeight400, FontWeight300, FontWeight200, FontWeight100 }
};
unsigned ruleSetIndex = static_cast<unsigned>(desiredTraits.weight());
ASSERT(ruleSetIndex < fallbackRuleSets);
const FontWeight* weightFallbackRule = weightFallbackRuleSets[ruleSetIndex];
for (unsigned i = 0; i < rulesPerSet; ++i) {
if (secondTraits.weight() == weightFallbackRule[i])
return false;
if (firstTraits.weight() == weightFallbackRule[i])
return true;
}
return false;
}