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Prevent buffer overrun when getting the glyph images

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The change 35bc3dc45a moved some padding out
of QTextureGlyphCache into the font engines directly, however this was not
done for the DirectWrite font engine so it caused a buffer overrun.

Task-number: QTBUG-41782
Change-Id: I4e643159036f06c5edd8a742dc6694d517a47826
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
This commit is contained in:
Andy Shaw 2015-01-05 14:26:03 +01:00
parent 5517d1fde5
commit bb16ceac68
3 changed files with 32 additions and 3 deletions
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17
src/plugins/platforms/windows/qwindowsfontenginedirectwrite.cpp
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@ -515,8 +515,9 @@ QImage QWindowsFontEngineDirectWrite::imageForGlyph(glyph_t t,
const QTransform &xform)
{
glyph_metrics_t metrics = QFontEngine::boundingBox(t, xform);
int width = (metrics.width + margin * 2 + 4).ceil().toInt() ;
int height = (metrics.height + margin * 2 + 4).ceil().toInt();
// This needs to be kept in sync with alphaMapBoundingBox
int width = (metrics.width + margin * 2).ceil().toInt() ;
int height = (metrics.height + margin * 2).ceil().toInt();
UINT16 glyphIndex = t;
FLOAT glyphAdvance = metrics.xoff.toReal();
@ -699,6 +700,18 @@ QString QWindowsFontEngineDirectWrite::fontNameSubstitute(const QString &familyN
return QSettings(QLatin1String(keyC), QSettings::NativeFormat).value(familyName, familyName).toString();
}
glyph_metrics_t QWindowsFontEngineDirectWrite::alphaMapBoundingBox(glyph_t glyph, QFixed pos, const QTransform &matrix, GlyphFormat format)
{
Q_UNUSED(pos);
int margin = 0;
if (format == QFontEngine::Format_A32 || format == QFontEngine::Format_ARGB)
margin = glyphMargin(QFontEngine::Format_A32);
glyph_metrics_t gm = QFontEngine::boundingBox(glyph, matrix);
gm.width += margin * 2;
gm.height += margin * 2;
return gm;
}
QT_END_NAMESPACE
#endif // QT_NO_DIRECTWRITE

1
src/plugins/platforms/windows/qwindowsfontenginedirectwrite.h
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@ -75,6 +75,7 @@ public:
glyph_metrics_t boundingBox(const QGlyphLayout &glyphs);
glyph_metrics_t boundingBox(glyph_t g);
glyph_metrics_t alphaMapBoundingBox(glyph_t glyph, QFixed, const QTransform &matrix, GlyphFormat);
QFixed ascent() const;
QFixed descent() const;

17
tests/auto/gui/painting/qpainter/tst_qpainter.cpp
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@ -289,7 +289,7 @@ private slots:
void blendARGBonRGB();
void RasterOp_NotDestination();
void drawTextNoHinting();
private:
void fillData();
void setPenColor(QPainter& p);
@ -4812,6 +4812,21 @@ void tst_QPainter::RasterOp_NotDestination()
QCOMPARE(pixel, 0xff00ffff);
}
void tst_QPainter::drawTextNoHinting()
{
{
QImage image(250, 250, QImage::Format_RGB32);
QPainter p(&image);
QFont font("Arial", 8);
font.setHintingPreference(QFont::PreferNoHinting);
font.setStyleStrategy(QFont::PreferAntialias);
p.setFont(font);
p.drawText(image.rect(), "ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz");
}
// Testing for a crash when DirectWrite is used on Windows
QVERIFY(true);
}
QTEST_MAIN(tst_QPainter)
#include "tst_qpainter.moc"