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QTextEngine::shapeTextWithHarfbuzz() code simplification

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Move (sub-)item boundaries calculation (aka fallback font items)
outside to be shared with HarfBuzz-NG based shaping a bit later.

This implementation might silently break words or even graphemes
so it needs to be reworked anyways; keeping it in a single place
would make futher work some cheaper.

Change-Id: Id9ca82b40e90b07ca29363fd43247c5fa9897eff
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
This commit is contained in:
Konstantin Ritt 2013-09-06 07:12:20 +03:00 committed by The Qt Project
parent 149f3efc39
commit 7b8f33fb78
2 changed files with 69 additions and 66 deletions
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133
src/gui/text/qtextengine.cpp
View File

@ -883,9 +883,6 @@ void QTextEngine::shapeText(int item) const
const ushort *string = reinterpret_cast<const ushort *>(layoutData->string.constData()) + si.position;
const int itemLength = length(item);
if (!ensureSpace(itemLength))
return; // ### report OOM error somehow
QString casedString;
if (si.analysis.flags && si.analysis.flags <= QScriptAnalysis::SmallCaps) {
casedString.resize(itemLength);
@ -910,8 +907,61 @@ void QTextEngine::shapeText(int item) const
string = reinterpret_cast<const ushort *>(casedString.constData());
}
if (!ensureSpace(itemLength)) {
// ### report OOM error somehow
return;
}
QFontEngine *fontEngine = this->fontEngine(si, &si.ascent, &si.descent, &si.leading);
// split up the item into parts that come from different font engines
QVector<uint> itemBoundaries;
itemBoundaries.reserve(16);
// k * 2 entries, array[k] == index in string, array[k + 1] == index in glyphs
itemBoundaries.append(0);
itemBoundaries.append(0);
if (fontEngine->type() == QFontEngine::Multi) {
// ask the font engine to find out which glyphs (as an index in the specific font)
// to use for the text in one item.
QGlyphLayout initialGlyphs = availableGlyphs(&si);
int nGlyphs = initialGlyphs.numGlyphs;
QFontEngine::ShaperFlags shaperFlags(QFontEngine::GlyphIndicesOnly);
if (si.analysis.bidiLevel % 2)
shaperFlags |= QFontEngine::RightToLeft;
if (!fontEngine->stringToCMap(reinterpret_cast<const QChar *>(string), itemLength, &initialGlyphs, &nGlyphs, shaperFlags)) {
nGlyphs = qMax(nGlyphs, itemLength); // ### needed for QFontEngine::stringToCMap() to not fail twice
if (!ensureSpace(nGlyphs)) {
// ### report OOM error somehow
return;
}
initialGlyphs = availableGlyphs(&si);
if (!fontEngine->stringToCMap(reinterpret_cast<const QChar *>(string), itemLength, &initialGlyphs, &nGlyphs, shaperFlags)) {
// ### if this happens there is a bug in the fontengine
return;
}
}
uint lastEngine = 0;
for (int i = 0, glyph_pos = 0; i < itemLength; ++i, ++glyph_pos) {
const uint engineIdx = initialGlyphs.glyphs[glyph_pos] >> 24;
if (lastEngine != engineIdx && glyph_pos > 0) {
itemBoundaries.append(i);
itemBoundaries.append(glyph_pos);
lastEngine = engineIdx;
QFontEngine *actualFontEngine = static_cast<QFontEngineMulti *>(fontEngine)->engine(engineIdx);
si.ascent = qMax(actualFontEngine->ascent(), si.ascent);
si.descent = qMax(actualFontEngine->descent(), si.descent);
si.leading = qMax(actualFontEngine->leading(), si.leading);
}
if (QChar::isHighSurrogate(string[i]) && i + 1 < itemLength && QChar::isLowSurrogate(string[i + 1]))
++i;
}
}
bool kerningEnabled;
bool letterSpacingIsAbsolute;
QFixed letterSpacing, wordSpacing;
@ -935,9 +985,13 @@ void QTextEngine::shapeText(int item) const
letterSpacing *= font.d->dpi / qt_defaultDpiY();
}
si.num_glyphs = shapeTextWithHarfbuzz(si, string, itemLength, fontEngine, kerningEnabled);
if (!si.num_glyphs)
return; // ### report shaping errors somehow
si.num_glyphs = shapeTextWithHarfbuzz(si, string, itemLength, fontEngine, itemBoundaries, kerningEnabled);
if (si.num_glyphs == 0) {
// ### report shaping errors somehow
return;
}
layoutData->used += si.num_glyphs;
QGlyphLayout glyphs = shapedGlyphs(&si);
@ -998,22 +1052,7 @@ Q_STATIC_ASSERT(sizeof(HB_GlyphAttributes) == sizeof(QGlyphAttributes));
Q_STATIC_ASSERT(sizeof(HB_Fixed) == sizeof(QFixed));
Q_STATIC_ASSERT(sizeof(HB_FixedPoint) == sizeof(QFixedPoint));
// ask the font engine to find out which glyphs (as an index in the specific font) to use for the text in one item.
static bool stringToGlyphs(HB_ShaperItem *item, QGlyphLayout *glyphs, QFontEngine *fontEngine)
{
int nGlyphs = item->num_glyphs;
QFontEngine::ShaperFlags shaperFlags(QFontEngine::GlyphIndicesOnly);
if (item->item.bidiLevel % 2)
shaperFlags |= QFontEngine::RightToLeft;
bool result = fontEngine->stringToCMap(reinterpret_cast<const QChar *>(item->string + item->item.pos), item->item.length, glyphs, &nGlyphs, shaperFlags);
item->num_glyphs = nGlyphs;
glyphs->numGlyphs = nGlyphs;
return result;
}
int QTextEngine::shapeTextWithHarfbuzz(QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, bool kerningEnabled) const
int QTextEngine::shapeTextWithHarfbuzz(const QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, const QVector<uint> &itemBoundaries, bool kerningEnabled) const
{
HB_ShaperItem entire_shaper_item;
memset(&entire_shaper_item, 0, sizeof(entire_shaper_item));
@ -1030,45 +1069,13 @@ int QTextEngine::shapeTextWithHarfbuzz(QScriptItem &si, const ushort *string, in
if (option.useDesignMetrics())
entire_shaper_item.shaperFlags |= HB_ShaperFlag_UseDesignMetrics;
entire_shaper_item.num_glyphs = itemLength;
QGlyphLayout initialGlyphs = availableGlyphs(&si).mid(0, entire_shaper_item.num_glyphs);
if (!stringToGlyphs(&entire_shaper_item, &initialGlyphs, fontEngine)) {
if (!ensureSpace(entire_shaper_item.num_glyphs))
return 0;
initialGlyphs = availableGlyphs(&si).mid(0, entire_shaper_item.num_glyphs);
if (!stringToGlyphs(&entire_shaper_item, &initialGlyphs, fontEngine)) {
// ############ if this happens there's a bug in the fontengine
return 0;
}
// ensure we are not asserting in HB_HeuristicSetGlyphAttributes()
entire_shaper_item.num_glyphs = 0;
for (int i = 0; i < itemLength; ++i, ++entire_shaper_item.num_glyphs) {
if (QChar::isHighSurrogate(string[i]) && i + 1 < itemLength && QChar::isLowSurrogate(string[i + 1]))
++i;
}
// split up the item into parts that come from different font engines.
QVarLengthArray<int> itemBoundaries(2);
// k * 2 entries, array[k] == index in string, array[k + 1] == index in glyphs
itemBoundaries[0] = entire_shaper_item.item.pos;
itemBoundaries[1] = 0;
if (fontEngine->type() == QFontEngine::Multi) {
uint lastEngine = 0;
int charIdx = entire_shaper_item.item.pos;
const int stringEnd = charIdx + entire_shaper_item.item.length;
for (quint32 i = 0; i < entire_shaper_item.num_glyphs; ++i, ++charIdx) {
uint engineIdx = initialGlyphs.glyphs[i] >> 24;
if (engineIdx != lastEngine && i > 0) {
itemBoundaries.append(charIdx);
itemBoundaries.append(i);
}
lastEngine = engineIdx;
if (QChar::isHighSurrogate(entire_shaper_item.string[charIdx])
&& charIdx < stringEnd - 1
&& QChar::isLowSurrogate(entire_shaper_item.string[charIdx + 1]))
++charIdx;
}
}
int remaining_glyphs = entire_shaper_item.num_glyphs;
int glyph_pos = 0;
@ -1093,18 +1100,14 @@ int QTextEngine::shapeTextWithHarfbuzz(QScriptItem &si, const ushort *string, in
uint engineIdx = 0;
if (fontEngine->type() == QFontEngine::Multi) {
engineIdx = uint(availableGlyphs(&si).glyphs[glyph_pos] >> 24);
actualFontEngine = static_cast<QFontEngineMulti *>(fontEngine)->engine(engineIdx);
si.ascent = qMax(actualFontEngine->ascent(), si.ascent);
si.descent = qMax(actualFontEngine->descent(), si.descent);
si.leading = qMax(actualFontEngine->leading(), si.leading);
shaper_item.glyphIndicesPresent = true;
}
shaper_item.font = (HB_Font)actualFontEngine->harfbuzzFont();
shaper_item.face = (HB_Face)actualFontEngine->harfbuzzFace();
shaper_item.glyphIndicesPresent = true;
remaining_glyphs -= shaper_item.initialGlyphCount;
do {

2
src/gui/text/qtextengine_p.h
View File

@ -668,7 +668,7 @@ private:
void setBoundary(int strPos) const;
void addRequiredBoundaries() const;
void shapeText(int item) const;
int shapeTextWithHarfbuzz(QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, bool kerningEnabled) const;
int shapeTextWithHarfbuzz(const QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, const QVector<uint> &itemBoundaries, bool kerningEnabled) const;
void splitItem(int item, int pos) const;
int endOfLine(int lineNum);