bool HarfBuzzShaper::extractShapeResults(hb_buffer_t* harfBuzzBuffer,
ShapeResult* shapeResult,
bool& fontCycleQueued, const HolesQueueItem& currentQueueItem,
const SimpleFontData* currentFont,
UScriptCode currentRunScript,
bool isLastResort)
{
enum ClusterResult {
Shaped,
NotDef,
Unknown
};
ClusterResult currentClusterResult = Unknown;
ClusterResult previousClusterResult = Unknown;
unsigned previousCluster = 0;
unsigned currentCluster = 0;
// Find first notdef glyph in harfBuzzBuffer.
unsigned numGlyphs = hb_buffer_get_length(harfBuzzBuffer);
hb_glyph_info_t* glyphInfo = hb_buffer_get_glyph_infos(harfBuzzBuffer, 0);
unsigned lastChangePosition = 0;
if (!numGlyphs) {
DLOG(ERROR) << "HarfBuzz returned empty glyph buffer after shaping.";
return false;
}
for (unsigned glyphIndex = 0; glyphIndex <= numGlyphs; ++glyphIndex) {
// Iterating by clusters, check for when the state switches from shaped
// to non-shaped and vice versa. Taking into account the edge cases of
// beginning of the run and end of the run.
previousCluster = currentCluster;
currentCluster = glyphInfo[glyphIndex].cluster;
if (glyphIndex < numGlyphs) {
// Still the same cluster, merge shaping status.
if (previousCluster == currentCluster && glyphIndex != 0) {
if (glyphInfo[glyphIndex].codepoint == 0) {
currentClusterResult = NotDef;
} else {
// We can only call the current cluster fully shapped, if
// all characters that are part of it are shaped, so update
// currentClusterResult to Shaped only if the previous
// characters have been shaped, too.
currentClusterResult = currentClusterResult == Shaped ? Shaped : NotDef;
}
continue;
}
// We've moved to a new cluster.
previousClusterResult = currentClusterResult;
currentClusterResult = glyphInfo[glyphIndex].codepoint == 0 ? NotDef : Shaped;
} else {
// The code below operates on the "flanks"/changes between NotDef
// and Shaped. In order to keep the code below from explictly
// dealing with character indices and run end, we explicitly
// terminate the cluster/run here by setting the result value to the
// opposite of what it was, leading to atChange turning true.
previousClusterResult = currentClusterResult;
currentClusterResult = currentClusterResult == NotDef ? Shaped : NotDef;
}
bool atChange = (previousClusterResult != currentClusterResult) && previousClusterResult != Unknown;
if (!atChange)
continue;
// Compute the range indices of consecutive shaped or .notdef glyphs.
// Cluster information for RTL runs becomes reversed, e.g. character 0
// has cluster index 5 in a run of 6 characters.
unsigned numCharacters = 0;
unsigned numGlyphsToInsert = 0;
unsigned startIndex = 0;
if (HB_DIRECTION_IS_FORWARD(hb_buffer_get_direction(harfBuzzBuffer))) {
startIndex = glyphInfo[lastChangePosition].cluster;
if (glyphIndex == numGlyphs) {
numCharacters = currentQueueItem.m_startIndex + currentQueueItem.m_numCharacters - glyphInfo[lastChangePosition].cluster;
numGlyphsToInsert = numGlyphs - lastChangePosition;
} else {
numCharacters = glyphInfo[glyphIndex].cluster - glyphInfo[lastChangePosition].cluster;
numGlyphsToInsert = glyphIndex - lastChangePosition;
}
} else {
// Direction Backwards
startIndex = glyphInfo[glyphIndex - 1].cluster;
if (lastChangePosition == 0) {
numCharacters = currentQueueItem.m_startIndex + currentQueueItem.m_numCharacters - glyphInfo[glyphIndex - 1].cluster;
} else {
numCharacters = glyphInfo[lastChangePosition - 1].cluster - glyphInfo[glyphIndex - 1].cluster;
}
numGlyphsToInsert = glyphIndex - lastChangePosition;
}
if (currentClusterResult == Shaped && !isLastResort) {
// Now it's clear that we need to continue processing.
if (!fontCycleQueued) {
appendToHolesQueue(HolesQueueNextFont, 0, 0);
fontCycleQueued = true;
}
// Here we need to put character positions.
ASSERT(numCharacters);
appendToHolesQueue(HolesQueueRange, startIndex, numCharacters);
}
// If numCharacters is 0, that means we hit a NotDef before shaping the
// whole grapheme. We do not append it here. For the next glyph we
// encounter, atChange will be true, and the characters corresponding to
// the grapheme will be added to the TODO queue again, attempting to
// shape the whole grapheme with the next font.
// When we're getting here with the last resort font, we have no other
// choice than adding boxes to the ShapeResult.
if ((currentClusterResult == NotDef && numCharacters) || isLastResort) {
hb_direction_t direction = TextDirectionToHBDirection(
m_textRun.direction(),
m_font->getFontDescription().orientation(), currentFont);
// Here we need to specify glyph positions.
ShapeResult::RunInfo* run = new ShapeResult::RunInfo(currentFont,
direction, ICUScriptToHBScript(currentRunScript),
startIndex, numGlyphsToInsert, numCharacters);
shapeResult->insertRun(adoptPtr(run), lastChangePosition,
numGlyphsToInsert,
harfBuzzBuffer);
}
lastChangePosition = glyphIndex;
}
return true;
}
PassRefPtr<ShapeResult> HarfBuzzShaper::shapeResult()
{
RefPtr<ShapeResult> result = ShapeResult::create(m_font,
m_normalizedBufferLength, m_textRun.direction());
HarfBuzzScopedPtr<hb_buffer_t> harfBuzzBuffer(hb_buffer_create(), hb_buffer_destroy);
const FontDescription& fontDescription = m_font->getFontDescription();
const String& localeString = fontDescription.locale();
CString locale = localeString.latin1();
const hb_language_t language = hb_language_from_string(locale.data(), locale.length());
bool needsCapsHandling = fontDescription.variantCaps() != FontDescription::CapsNormal;
OpenTypeCapsSupport capsSupport;
RunSegmenter::RunSegmenterRange segmentRange = {
0,
0,
USCRIPT_INVALID_CODE,
OrientationIterator::OrientationInvalid,
FontFallbackPriority::Invalid };
RunSegmenter runSegmenter(
m_normalizedBuffer.get(),
m_normalizedBufferLength,
m_font->getFontDescription().orientation());
Vector<UChar32> fallbackCharsHint;
// TODO: Check whether this treatAsZerowidthspace from the previous script
// segmentation plays a role here, does the new scriptRuniterator handle that correctly?
while (runSegmenter.consume(&segmentRange)) {
RefPtr<FontFallbackIterator> fallbackIterator =
m_font->createFontFallbackIterator(
segmentRange.fontFallbackPriority);
appendToHolesQueue(HolesQueueNextFont, 0, 0);
appendToHolesQueue(HolesQueueRange, segmentRange.start, segmentRange.end - segmentRange.start);
const SimpleFontData* currentFont = nullptr;
RefPtr<UnicodeRangeSet> currentFontRangeSet;
bool fontCycleQueued = false;
while (m_holesQueue.size()) {
HolesQueueItem currentQueueItem = m_holesQueue.takeFirst();
if (currentQueueItem.m_action == HolesQueueNextFont) {
// For now, we're building a character list with which we probe
// for needed fonts depending on the declared unicode-range of a
// segmented CSS font. Alternatively, we can build a fake font
// for the shaper and check whether any glyphs were found, or
// define a new API on the shaper which will give us coverage
// information?
if (!collectFallbackHintChars(fallbackCharsHint, fallbackIterator->needsHintList())) {
// Give up shaping since we cannot retrieve a font fallback
// font without a hintlist.
m_holesQueue.clear();
break;
}
FontDataForRangeSet nextFontDataForRangeSet = fallbackIterator->next(fallbackCharsHint);
currentFont = nextFontDataForRangeSet.fontData();
currentFontRangeSet = nextFontDataForRangeSet.ranges();
if (!currentFont) {
ASSERT(!m_holesQueue.size());
break;
}
fontCycleQueued = false;
continue;
}
SmallCapsIterator::SmallCapsBehavior smallCapsBehavior = SmallCapsIterator::SmallCapsSameCase;
if (needsCapsHandling) {
capsSupport = OpenTypeCapsSupport(currentFont->platformData().harfBuzzFace(),
fontDescription.variantCaps(),
ICUScriptToHBScript(segmentRange.script));
if (capsSupport.needsRunCaseSplitting())
splitUntilNextCaseChange(currentQueueItem, smallCapsBehavior);
}
ASSERT(currentQueueItem.m_numCharacters);
const SimpleFontData* smallcapsAdjustedFont = needsCapsHandling
&& capsSupport.needsSyntheticFont(smallCapsBehavior)
? currentFont->smallCapsFontData(fontDescription).get()
: currentFont;
// Compatibility with SimpleFontData approach of keeping a flag for overriding drawing direction.
// TODO: crbug.com/506224 This should go away in favor of storing that information elsewhere, for example in
// ShapeResult.
const SimpleFontData* directionAndSmallCapsAdjustedFont = fontDataAdjustedForOrientation(smallcapsAdjustedFont,
m_font->getFontDescription().orientation(),
segmentRange.renderOrientation);
CaseMapIntend caseMapIntend = CaseMapIntend::KeepSameCase;
if (needsCapsHandling) {
caseMapIntend = capsSupport.needsCaseChange(smallCapsBehavior);
}
CaseMappingHarfBuzzBufferFiller(
caseMapIntend,
harfBuzzBuffer.get(),
m_normalizedBuffer.get(),
m_normalizedBufferLength,
currentQueueItem.m_startIndex,
currentQueueItem.m_numCharacters);
CapsFeatureSettingsScopedOverlay capsOverlay(m_features, capsSupport.fontFeatureToUse(smallCapsBehavior));
if (!shapeRange(harfBuzzBuffer.get(),
currentQueueItem.m_startIndex,
currentQueueItem.m_numCharacters,
directionAndSmallCapsAdjustedFont,
currentFontRangeSet,
segmentRange.script,
language))
DLOG(ERROR) << "Shaping range failed.";
if (!extractShapeResults(harfBuzzBuffer.get(),
result.get(),
fontCycleQueued,
currentQueueItem,
directionAndSmallCapsAdjustedFont,
segmentRange.script,
!fallbackIterator->hasNext()))
DLOG(ERROR) << "Shape result extraction failed.";
hb_buffer_reset(harfBuzzBuffer.get());
}
}
return result.release();
}
PassRefPtr<ShapeResult> HarfBuzzShaper::shapeResult()
{
RefPtr<ShapeResult> result = ShapeResult::create(m_font,
m_normalizedBufferLength, m_textRun.direction());
HarfBuzzScopedPtr<hb_buffer_t> harfBuzzBuffer(hb_buffer_create(), hb_buffer_destroy);
const FontDescription& fontDescription = m_font->getFontDescription();
const String& localeString = fontDescription.locale();
CString locale = localeString.latin1();
const hb_language_t language = hb_language_from_string(locale.data(), locale.length());
RunSegmenter::RunSegmenterRange segmentRange = {
0,
0,
USCRIPT_INVALID_CODE,
OrientationIterator::OrientationInvalid,
SmallCapsIterator::SmallCapsSameCase,
FontFallbackPriority::Invalid };
RunSegmenter runSegmenter(
m_normalizedBuffer.get(),
m_normalizedBufferLength,
m_font->getFontDescription().orientation(),
fontDescription.variant());
Vector<UChar32> fallbackCharsHint;
// TODO: Check whether this treatAsZerowidthspace from the previous script
// segmentation plays a role here, does the new scriptRuniterator handle that correctly?
while (runSegmenter.consume(&segmentRange)) {
RefPtr<FontFallbackIterator> fallbackIterator =
m_font->createFontFallbackIterator(
segmentRange.fontFallbackPriority);
appendToHolesQueue(HolesQueueNextFont, 0, 0);
appendToHolesQueue(HolesQueueRange, segmentRange.start, segmentRange.end - segmentRange.start);
const SimpleFontData* currentFont = nullptr;
RefPtr<UnicodeRangeSet> currentFontRangeSet;
bool fontCycleQueued = false;
while (m_holesQueue.size()) {
HolesQueueItem currentQueueItem = m_holesQueue.takeFirst();
if (currentQueueItem.m_action == HolesQueueNextFont) {
// For now, we're building a character list with which we probe
// for needed fonts depending on the declared unicode-range of a
// segmented CSS font. Alternatively, we can build a fake font
// for the shaper and check whether any glyphs were found, or
// define a new API on the shaper which will give us coverage
// information?
if (!collectFallbackHintChars(fallbackCharsHint, fallbackIterator->needsHintList())) {
// Give up shaping since we cannot retrieve a font fallback
// font without a hintlist.
m_holesQueue.clear();
break;
}
FontDataForRangeSet nextFontDataForRangeSet = fallbackIterator->next(fallbackCharsHint);
currentFont = nextFontDataForRangeSet.fontData().get();
currentFontRangeSet = nextFontDataForRangeSet.ranges();
if (!currentFont) {
ASSERT(!m_holesQueue.size());
break;
}
fontCycleQueued = false;
continue;
}
// TODO crbug.com/522964: Only use smallCapsFontData when the font does not support true smcp. The spec
// says: "To match the surrounding text, a font may provide alternate glyphs for caseless characters when
// these features are enabled but when a user agent simulates small capitals, it must not attempt to
// simulate alternates for codepoints which are considered caseless."
const SimpleFontData* smallcapsAdjustedFont = segmentRange.smallCapsBehavior == SmallCapsIterator::SmallCapsUppercaseNeeded
? currentFont->smallCapsFontData(fontDescription).get()
: currentFont;
// Compatibility with SimpleFontData approach of keeping a flag for overriding drawing direction.
// TODO: crbug.com/506224 This should go away in favor of storing that information elsewhere, for example in
// ShapeResult.
const SimpleFontData* directionAndSmallCapsAdjustedFont = fontDataAdjustedForOrientation(smallcapsAdjustedFont,
m_font->getFontDescription().orientation(),
segmentRange.renderOrientation);
if (!shapeRange(harfBuzzBuffer.get(),
currentQueueItem.m_startIndex,
currentQueueItem.m_numCharacters,
directionAndSmallCapsAdjustedFont,
currentFontRangeSet,
segmentRange.script,
language))
DLOG(ERROR) << "Shaping range failed.";
if (!extractShapeResults(harfBuzzBuffer.get(),
result.get(),
fontCycleQueued,
currentQueueItem,
directionAndSmallCapsAdjustedFont,
segmentRange.script,
!fallbackIterator->hasNext()))
DLOG(ERROR) << "Shape result extraction failed.";
hb_buffer_reset(harfBuzzBuffer.get());
}
}
return result.release();
}
