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Add HarfBuzz-NG support 

Some features are of limited usefulness for now (same as with HB-old):
* mixed scripts cases aren't handled correctly due to an outdated
  script and bidi itemization implementation;
* language-by-script detection: the only fallback to locale's LANG is used

Some features are missing entirely (in compare to HB-old):
* justification points support: not implemented in HarfBuzz-NG

Task-number: QTBUG-18980
Task-number: QTBUG-14590
Task-number: QTBUG-16128

Change-Id: Ic98a10054be5fac55224ef31c7261168c0bf8739
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
bb10
Konstantin Ritt 2013-09-07 22:56:18 +03:00 committed by The Qt Project
parent 19b7afca52
commit c72eb0372b
2 changed files with 178 additions and 1 deletions
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176
src/gui/text/qtextengine.cpp
View File

@ -868,6 +868,9 @@ void QTextEngine::shapeLine(const QScriptLine &line)
}
}
#ifdef QT_ENABLE_HARFBUZZ_NG
extern bool useHarfbuzzNG; // defined in qfontengine.cpp
#endif
void QTextEngine::shapeText(int item) const
{
@ -985,6 +988,11 @@ void QTextEngine::shapeText(int item) const
letterSpacing *= font.d->dpi / qt_defaultDpiY();
}
#ifdef QT_ENABLE_HARFBUZZ_NG
if (useHarfbuzzNG)
si.num_glyphs = shapeTextWithHarfbuzzNG(si, string, itemLength, fontEngine, itemBoundaries, kerningEnabled);
else
#endif
si.num_glyphs = shapeTextWithHarfbuzz(si, string, itemLength, fontEngine, itemBoundaries, kerningEnabled);
if (si.num_glyphs == 0) {
Q_UNREACHABLE(); // ### report shaping errors somehow
@ -1041,6 +1049,163 @@ static inline void moveGlyphData(const QGlyphLayout &destination, const QGlyphLa
}
}
#ifdef QT_ENABLE_HARFBUZZ_NG
QT_BEGIN_INCLUDE_NAMESPACE
#include "qharfbuzzng_p.h"
QT_END_INCLUDE_NAMESPACE
int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, const QVector<uint> &itemBoundaries, bool kerningEnabled) const
{
hb_buffer_t *buffer = hb_buffer_create();
hb_buffer_set_unicode_funcs(buffer, hb_qt_get_unicode_funcs());
hb_buffer_pre_allocate(buffer, itemLength);
if (!hb_buffer_allocation_successful(buffer)) {
hb_buffer_destroy(buffer);
return 0;
}
hb_segment_properties_t props = HB_SEGMENT_PROPERTIES_DEFAULT;
props.direction = si.analysis.bidiLevel % 2 ? HB_DIRECTION_RTL : HB_DIRECTION_LTR;
props.script = hb_qt_script_to_script(QChar::Script(si.analysis.script));
// ### props.language = hb_language_get_default_for_script(props.script);
uint glyphs_shaped = 0;
int remaining_glyphs = itemLength;
for (int k = 0; k < itemBoundaries.size(); k += 2) { // for the +2, see the comment at the definition of itemBoundaries
uint item_pos = itemBoundaries[k];
uint item_length = itemLength;
uint item_glyph_pos = itemBoundaries[k + 1];
if (k + 3 < itemBoundaries.size())
item_length = itemBoundaries[k + 2];
item_length -= item_pos;
QFontEngine *actualFontEngine = fontEngine;
uint engineIdx = 0;
if (fontEngine->type() == QFontEngine::Multi) {
engineIdx = availableGlyphs(&si).glyphs[glyphs_shaped] >> 24;
actualFontEngine = static_cast<QFontEngineMulti *>(fontEngine)->engine(engineIdx);
}
// prepare buffer
hb_buffer_clear_contents(buffer);
hb_buffer_add_utf16(buffer, reinterpret_cast<const uint16_t *>(string) + item_pos, item_length, 0, item_length);
hb_buffer_set_segment_properties(buffer, &props);
hb_buffer_guess_segment_properties(buffer);
uint buffer_flags = HB_BUFFER_FLAG_DEFAULT;
// Symbol encoding used to encode various crap in the 32..255 character code range,
// and thus might override U+00AD [SHY]; avoid hiding default ignorables
if (actualFontEngine->symbol)
buffer_flags |= HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES;
hb_buffer_set_flags(buffer, hb_buffer_flags_t(buffer_flags));
const uint num_codes = hb_buffer_get_length(buffer);
{
// adjust clusters
hb_glyph_info_t *infos = hb_buffer_get_glyph_infos(buffer, 0);
const ushort *uc = string + item_pos;
for (uint i = 0, code_pos = 0; i < item_length; ++i, ++code_pos) {
if (QChar::isHighSurrogate(uc[i]) && i + 1 < item_length && QChar::isLowSurrogate(uc[i + 1]))
++i;
infos[code_pos].cluster = code_pos + item_glyph_pos;
}
}
// shape
bool shapedOk = false;
if (hb_font_t *hb_font = hb_qt_font_get_for_engine(actualFontEngine)) {
hb_qt_font_set_use_design_metrics(hb_font, option.useDesignMetrics() ? uint(QFontEngine::DesignMetrics) : 0); // ###
const hb_feature_t features[1] = {
{ HB_TAG('k','e','r','n'), !!kerningEnabled, 0, -1 }
};
const int num_features = 1;
shapedOk = hb_shape_full(hb_font, buffer, features, num_features, 0);
hb_font_destroy(hb_font);
}
if (!shapedOk) {
hb_buffer_destroy(buffer);
return 0;
}
if (si.analysis.bidiLevel % 2)
hb_buffer_reverse(buffer);
remaining_glyphs -= num_codes;
// ensure we have enough space for shaped glyphs and metrics
const uint num_glyphs = hb_buffer_get_length(buffer);
if (num_glyphs == 0 || !ensureSpace(glyphs_shaped + num_glyphs + remaining_glyphs)) {
hb_buffer_destroy(buffer);
return 0;
}
// fetch the shaped glyphs and metrics
QGlyphLayout g = availableGlyphs(&si).mid(glyphs_shaped, num_glyphs);
if (num_glyphs > num_codes)
moveGlyphData(g.mid(num_glyphs), g.mid(num_codes), remaining_glyphs);
ushort *log_clusters = logClusters(&si) + item_pos;
hb_glyph_info_t *infos = hb_buffer_get_glyph_infos(buffer, 0);
hb_glyph_position_t *positions = hb_buffer_get_glyph_positions(buffer, 0);
uint last_cluster = -1;
for (uint i = 0; i < num_glyphs; ++i) {
g.glyphs[i] = infos[i].codepoint;
log_clusters[i] = infos[i].cluster;
g.advances_x[i] = QFixed::fromFixed(positions[i].x_advance);
g.advances_y[i] = QFixed::fromFixed(positions[i].y_advance);
g.offsets[i].x = QFixed::fromFixed(positions[i].x_offset);
g.offsets[i].y = QFixed::fromFixed(positions[i].y_offset);
if (infos[i].cluster != last_cluster) {
last_cluster = infos[i].cluster;
g.attributes[i].clusterStart = true;
}
}
{
// adjust clusters
uint glyph_pos = 0;
for (uint i = 0; i < item_length; ++i) {
if (i + item_pos != infos[glyph_pos].cluster) {
for (uint j = glyph_pos + 1; j < num_glyphs; ++j) {
if (i + item_pos <= infos[j].cluster) {
if (i + item_pos == infos[j].cluster)
glyph_pos = j;
break;
}
}
}
log_clusters[i] = glyph_pos + item_glyph_pos;
}
}
if (engineIdx != 0) {
for (quint32 i = 0; i < num_glyphs; ++i)
g.glyphs[i] |= (engineIdx << 24);
}
glyphs_shaped += num_glyphs;
}
hb_buffer_destroy(buffer);
return glyphs_shaped;
}
#endif // QT_ENABLE_HARFBUZZ_NG
QT_BEGIN_INCLUDE_NAMESPACE
#include <private/qharfbuzz_p.h>
@ -1369,13 +1534,22 @@ void QTextEngine::itemize() const
analysis->flags = QScriptAnalysis::None;
break;
}
analysis->script = hbscript_to_script(script_to_hbscript(analysis->script)); // retain the old behavior
#ifndef QT_ENABLE_HARFBUZZ_NG
analysis->script = hbscript_to_script(script_to_hbscript(analysis->script));
#endif
++uc;
++analysis;
}
if (option.flags() & QTextOption::ShowLineAndParagraphSeparators) {
(analysis-1)->flags = QScriptAnalysis::LineOrParagraphSeparator; // to exclude it from width
}
#ifdef QT_ENABLE_HARFBUZZ_NG
if (!useHarfbuzzNG) {
analysis = scriptAnalysis.data();
for (int i = 0; i < length; ++i)
analysis[i].script = hbscript_to_script(script_to_hbscript(analysis[i].script));
}
#endif
Itemizer itemizer(layoutData->string, scriptAnalysis.data(), layoutData->items);

3
src/gui/text/qtextengine_p.h
View File

@ -668,6 +668,9 @@ private:
void setBoundary(int strPos) const;
void addRequiredBoundaries() const;
void shapeText(int item) const;
#ifdef QT_ENABLE_HARFBUZZ_NG
int shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, const QVector<uint> &itemBoundaries, bool kerningEnabled) const;
#endif
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;