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QRawFont: improve performance and safety of glyphIndexesForString()

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As of 98c1eb1750, partially initialized
QGlyphLayout is ok for stringToCMap() if GlyphIndicesOnly flag is set,
thus we can use the glyphIndexes buffer directly and avoid copying.
Also add some checks to guarantee we're not falling into an undefined behavior
for the empty text or NULL buffer.

Change-Id: I662953703e4c65edbebabbe4b753972417d963f3
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
This commit is contained in:
Konstantin Ritt 2012-10-11 16:19:34 +03:00 committed by The Qt Project
parent e488d0f4da
commit 3e030a9652
3 changed files with 86 additions and 39 deletions
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70
src/gui/text/qrawfont.cpp
View File

@ -388,10 +388,7 @@ qreal QRawFont::unitsPerEm() const
*/
qreal QRawFont::lineThickness() const
{
if (!isValid())
return 0.0;
return d->fontEngine->lineThickness().toReal();
return d->isValid() ? d->fontEngine->lineThickness().toReal() : 0.0;
}
/*!
@ -400,10 +397,7 @@ qreal QRawFont::lineThickness() const
*/
qreal QRawFont::underlinePosition() const
{
if (!isValid())
return 0.0;
return d->fontEngine->underlinePosition().toReal();
return d->isValid() ? d->fontEngine->underlinePosition().toReal() : 0.0;
}
/*!
@ -459,23 +453,28 @@ int QRawFont::weight() const
*/
QVector<quint32> QRawFont::glyphIndexesForString(const QString &text) const
{
if (!d->isValid())
return QVector<quint32>();
QVector<quint32> glyphIndexes;
if (!d->isValid() || text.isEmpty())
return glyphIndexes;
int nglyphs = text.size();
QVarLengthGlyphLayoutArray glyphs(nglyphs);
if (!glyphIndexesForChars(text.data(), text.size(), glyphs.glyphs, &nglyphs)) {
glyphs.resize(nglyphs);
if (!glyphIndexesForChars(text.data(), text.size(), glyphs.glyphs, &nglyphs)) {
int numGlyphs = text.size();
glyphIndexes.resize(numGlyphs);
QGlyphLayout glyphs;
glyphs.numGlyphs = numGlyphs;
glyphs.glyphs = glyphIndexes.data();
if (!d->fontEngine->stringToCMap(text.data(), text.size(), &glyphs, &numGlyphs, QFontEngine::GlyphIndicesOnly)) {
glyphIndexes.resize(numGlyphs);
glyphs.numGlyphs = numGlyphs;
glyphs.glyphs = glyphIndexes.data();
if (!d->fontEngine->stringToCMap(text.data(), text.size(), &glyphs, &numGlyphs, QFontEngine::GlyphIndicesOnly)) {
Q_ASSERT_X(false, Q_FUNC_INFO, "stringToCMap shouldn't fail twice");
return QVector<quint32>();
}
}
QVector<quint32> glyphIndexes;
for (int i=0; i<nglyphs; ++i)
glyphIndexes.append(glyphs.glyphs[i]);
glyphIndexes.resize(numGlyphs);
return glyphIndexes;
}
@ -491,38 +490,32 @@ QVector<quint32> QRawFont::glyphIndexesForString(const QString &text) const
*/
bool QRawFont::glyphIndexesForChars(const QChar *chars, int numChars, quint32 *glyphIndexes, int *numGlyphs) const
{
if (!d->isValid())
Q_ASSERT(numGlyphs);
if (!d->isValid() || numChars <= 0) {
*numGlyphs = 0;
return false;
}
if (*numGlyphs <= 0 || !glyphIndexes) {
*numGlyphs = numChars;
return false;
}
QGlyphLayout glyphs;
glyphs.numGlyphs = *numGlyphs;
glyphs.glyphs = glyphIndexes;
return d->fontEngine->stringToCMap(chars, numChars, &glyphs, numGlyphs, QFontEngine::GlyphIndicesOnly);
}
/*!
\fn QVector<QPointF> QRawFont::advancesForGlyphIndexes(const QVector<quint32> &glyphIndexes) const
Returns the QRawFont's advances for each of the \a glyphIndexes in pixel units. The advances
give the distance from the position of a given glyph to where the next glyph should be drawn
to make it appear as if the two glyphs are unspaced.
\sa QTextLine::horizontalAdvance(), QFontMetricsF::width()
*/
QVector<QPointF> QRawFont::advancesForGlyphIndexes(const QVector<quint32> &glyphIndexes) const
{
if (!d->isValid())
return QVector<QPointF>();
int numGlyphs = glyphIndexes.size();
QVarLengthGlyphLayoutArray glyphs(numGlyphs);
memcpy(glyphs.glyphs, glyphIndexes.data(), numGlyphs * sizeof(quint32));
d->fontEngine->recalcAdvances(&glyphs, 0);
QVector<QPointF> advances;
for (int i=0; i<numGlyphs; ++i)
advances.append(QPointF(glyphs.advances_x[i].toReal(), glyphs.advances_y[i].toReal()));
return advances;
}
/*!
Returns the QRawFont's advances for each of the \a glyphIndexes in pixel units. The advances
@ -535,7 +528,8 @@ QVector<QPointF> QRawFont::advancesForGlyphIndexes(const QVector<quint32> &glyph
*/
bool QRawFont::advancesForGlyphIndexes(const quint32 *glyphIndexes, QPointF *advances, int numGlyphs) const
{
if (!d->isValid())
Q_ASSERT(glyphIndexes && advances);
if (!d->isValid() || numGlyphs <= 0)
return false;
QGlyphLayout glyphs;

10
src/gui/text/qrawfont.h
View File

@ -94,7 +94,7 @@ public:
int weight() const;
QVector<quint32> glyphIndexesForString(const QString &text) const;
QVector<QPointF> advancesForGlyphIndexes(const QVector<quint32> &glyphIndexes) const;
inline QVector<QPointF> advancesForGlyphIndexes(const QVector<quint32> &glyphIndexes) const;
bool glyphIndexesForChars(const QChar *chars, int numChars, quint32 *glyphIndexes, int *numGlyphs) const;
bool advancesForGlyphIndexes(const quint32 *glyphIndexes, QPointF *advances, int numGlyphs) const;
@ -147,6 +147,14 @@ private:
Q_DECLARE_SHARED(QRawFont)
inline QVector<QPointF> QRawFont::advancesForGlyphIndexes(const QVector<quint32> &glyphIndexes) const
{
QVector<QPointF> advances(glyphIndexes.size());
if (advancesForGlyphIndexes(glyphIndexes.constData(), advances.data(), glyphIndexes.size()))
return advances;
return QVector<QPointF>();
}
QT_END_NAMESPACE
QT_END_HEADER

45
tests/auto/gui/text/qrawfont/tst_qrawfont.cpp
View File

@ -267,6 +267,24 @@ void tst_QRawFont::glyphIndices()
expectedGlyphIndices << 44 << 83 << 83 << 70 << 69 << 86;
QCOMPARE(glyphIndices, expectedGlyphIndices);
glyphIndices = font.glyphIndexesForString(QString());
QVERIFY(glyphIndices.isEmpty());
QString str(QLatin1String("Foobar"));
int numGlyphs = str.size();
glyphIndices.resize(numGlyphs);
QVERIFY(!font.glyphIndexesForChars(str.constData(), 0, glyphIndices.data(), &numGlyphs));
QCOMPARE(numGlyphs, 0);
QVERIFY(!font.glyphIndexesForChars(str.constData(), str.size(), glyphIndices.data(), &numGlyphs));
QCOMPARE(numGlyphs, str.size());
QVERIFY(font.glyphIndexesForChars(str.constData(), str.size(), glyphIndices.data(), &numGlyphs));
QCOMPARE(numGlyphs, str.size());
QCOMPARE(glyphIndices, expectedGlyphIndices);
}
void tst_QRawFont::advances_data()
@ -310,6 +328,33 @@ void tst_QRawFont::advances()
QVERIFY(qFuzzyIsNull(advances.at(i).y()));
}
advances = font.advancesForGlyphIndexes(QVector<quint32>());
QVERIFY(advances.isEmpty());
int numGlyphs = glyphIndices.size();
advances.resize(numGlyphs);
QVERIFY(!font.advancesForGlyphIndexes(glyphIndices.constData(), advances.data(), 0));
QVERIFY(font.advancesForGlyphIndexes(glyphIndices.constData(), advances.data(), numGlyphs));
for (int i=0; i<glyphIndices.size(); ++i) {
#ifdef Q_OS_WIN
// In Windows, freetype engine returns advance of 9 when full hinting is used (default) for
// some of the glyphs.
if (font_d->fontEngine->type() == QFontEngine::Freetype
&& (hintingPreference == QFont::PreferFullHinting || hintingPreference == QFont::PreferDefaultHinting)
&& (i == 0 || i == 5)) {
QEXPECT_FAIL("", "Advance for some glyphs is not the expected with Windows Freetype engine (9 instead of 8)", Continue);
}
#endif
QVERIFY(qFuzzyCompare(qRound(advances.at(i).x()), 8.0));
if (supportsSubPixelPositions)
QVERIFY(advances.at(i).x() > 8.0);
QVERIFY(qFuzzyIsNull(advances.at(i).y()));
}
}
void tst_QRawFont::textLayout()