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-rw-r--r--src/gui/text/qfontengine.cpp60
-rw-r--r--src/gui/text/qfontengine_ft.cpp49
-rw-r--r--src/gui/text/qfontengine_ft_p.h4
-rw-r--r--src/gui/text/qfontengine_p.h8
-rw-r--r--src/gui/text/qtextengine_p.h16
-rw-r--r--src/gui/text/qtextlayout.cpp13
-rw-r--r--src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm10
-rw-r--r--src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h2
-rw-r--r--tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp7
9 files changed, 92 insertions, 77 deletions
diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index 2087bad9f6..102946b545 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -54,6 +54,7 @@
#include <private/qharfbuzz_p.h>
#include <algorithm>
+#include <limits.h>
QT_BEGIN_NAMESPACE
@@ -235,10 +236,14 @@ Q_AUTOTEST_EXPORT QList<QFontEngine *> QFontEngine_stopCollectingEngines()
// QFontEngine
+#define kBearingNotInitialized std::numeric_limits<qreal>::max()
+
QFontEngine::QFontEngine(Type type)
: m_type(type), ref(0),
font_(0), font_destroy_func(0),
- face_(0), face_destroy_func(0)
+ face_(0), face_destroy_func(0),
+ m_minLeftBearing(kBearingNotInitialized),
+ m_minRightBearing(kBearingNotInitialized)
{
faceData.user_data = this;
faceData.get_font_table = qt_get_font_table_default;
@@ -562,11 +567,55 @@ void QFontEngine::getGlyphPositions(const QGlyphLayout &glyphs, const QTransform
void QFontEngine::getGlyphBearings(glyph_t glyph, qreal *leftBearing, qreal *rightBearing)
{
glyph_metrics_t gi = boundingBox(glyph);
- bool isValid = gi.isValid();
if (leftBearing != 0)
- *leftBearing = isValid ? gi.x.toReal() : 0.0;
+ *leftBearing = gi.leftBearing().toReal();
if (rightBearing != 0)
- *rightBearing = isValid ? (gi.xoff - gi.x - gi.width).toReal() : 0.0;
+ *rightBearing = gi.rightBearing().toReal();
+}
+
+qreal QFontEngine::minLeftBearing() const
+{
+ if (m_minLeftBearing == kBearingNotInitialized)
+ minRightBearing(); // Initializes both (see below)
+
+ return m_minLeftBearing;
+}
+
+qreal QFontEngine::minRightBearing() const
+{
+ if (m_minRightBearing == kBearingNotInitialized) {
+
+ // To balance performance and correctness we only look at a subset of the
+ // possible glyphs in the font, based on which characters are more likely
+ // to have a left or right bearing.
+ static const ushort characterSubset[] = {
+ '(', 'C', 'F', 'K', 'V', 'X', 'Y', ']', '_', 'f', 'r', '|',
+ 127, 205, 645, 884, 922, 1070, 12386
+ };
+
+ // The font may have minimum bearings larger than 0, so we have to start at the max
+ m_minLeftBearing = m_minRightBearing = std::numeric_limits<qreal>::max();
+
+ for (uint i = 0; i < (sizeof(characterSubset) / sizeof(ushort)); ++i) {
+ const glyph_t glyph = glyphIndex(characterSubset[i]);
+ if (!glyph)
+ continue;
+
+ glyph_metrics_t glyphMetrics = const_cast<QFontEngine *>(this)->boundingBox(glyph);
+
+ // Glyphs with no contours shouldn't contribute to bearings
+ if (!glyphMetrics.width || !glyphMetrics.height)
+ continue;
+
+ m_minLeftBearing = qMin(m_minLeftBearing, glyphMetrics.leftBearing().toReal());
+ m_minRightBearing = qMin(m_minRightBearing, glyphMetrics.rightBearing().toReal());
+ }
+
+ if (m_minLeftBearing == kBearingNotInitialized || m_minRightBearing == kBearingNotInitialized)
+ qWarning() << "Failed to compute left/right minimum bearings for" << fontDef.family;
+ }
+
+ return m_minRightBearing;
}
glyph_metrics_t QFontEngine::tightBoundingBox(const QGlyphLayout &glyphs)
@@ -1469,8 +1518,7 @@ QFixed QFontEngine::lastRightBearing(const QGlyphLayout &glyphs, bool round)
glyph_t glyph = glyphs.glyphs[glyphs.numGlyphs - 1];
glyph_metrics_t gi = boundingBox(glyph);
if (gi.isValid())
- return round ? QFixed(qRound(gi.xoff - gi.x - gi.width))
- : QFixed(gi.xoff - gi.x - gi.width);
+ return round ? qRound(gi.rightBearing()) : gi.rightBearing();
}
return 0;
}
diff --git a/src/gui/text/qfontengine_ft.cpp b/src/gui/text/qfontengine_ft.cpp
index 246df127ad..0d28785aa1 100644
--- a/src/gui/text/qfontengine_ft.cpp
+++ b/src/gui/text/qfontengine_ft.cpp
@@ -688,7 +688,6 @@ bool QFontEngineFT::init(FaceId faceId, bool antialias, GlyphFormat format,
symbol = bool(fontDef.family.contains(QLatin1String("symbol"), Qt::CaseInsensitive));
}
- lbearing = rbearing = SHRT_MIN;
freetype->computeSize(fontDef, &xsize, &ysize, &defaultGlyphSet.outline_drawing);
FT_Face face = lockFace();
@@ -1258,54 +1257,6 @@ qreal QFontEngineFT::maxCharWidth() const
return metrics.max_advance >> 6;
}
-static const ushort char_table[] = {
- 40,
- 67,
- 70,
- 75,
- 86,
- 88,
- 89,
- 91,
- 95,
- 102,
- 114,
- 124,
- 127,
- 205,
- 645,
- 884,
- 922,
- 1070,
- 12386
-};
-
-static const int char_table_entries = sizeof(char_table)/sizeof(ushort);
-
-
-qreal QFontEngineFT::minLeftBearing() const
-{
- if (lbearing == SHRT_MIN)
- (void) minRightBearing(); // calculates both
- return lbearing.toReal();
-}
-
-qreal QFontEngineFT::minRightBearing() const
-{
- if (rbearing == SHRT_MIN) {
- lbearing = rbearing = 0;
- for (int i = 0; i < char_table_entries; ++i) {
- const glyph_t glyph = glyphIndex(char_table[i]);
- if (glyph != 0) {
- glyph_metrics_t gi = const_cast<QFontEngineFT *>(this)->boundingBox(glyph);
- lbearing = qMin(lbearing, gi.x);
- rbearing = qMin(rbearing, (gi.xoff - gi.x - gi.width));
- }
- }
- }
- return rbearing.toReal();
-}
-
QFixed QFontEngineFT::lineThickness() const
{
return line_thickness;
diff --git a/src/gui/text/qfontengine_ft_p.h b/src/gui/text/qfontengine_ft_p.h
index b81e51bf2e..83f9a4ef3d 100644
--- a/src/gui/text/qfontengine_ft_p.h
+++ b/src/gui/text/qfontengine_ft_p.h
@@ -208,8 +208,6 @@ private:
virtual QFixed averageCharWidth() const Q_DECL_OVERRIDE;
virtual qreal maxCharWidth() const Q_DECL_OVERRIDE;
- virtual qreal minLeftBearing() const Q_DECL_OVERRIDE;
- virtual qreal minRightBearing() const Q_DECL_OVERRIDE;
virtual QFixed lineThickness() const Q_DECL_OVERRIDE;
virtual QFixed underlinePosition() const Q_DECL_OVERRIDE;
@@ -324,8 +322,6 @@ private:
int xsize;
int ysize;
- mutable QFixed lbearing;
- mutable QFixed rbearing;
QFixed line_thickness;
QFixed underline_position;
diff --git a/src/gui/text/qfontengine_p.h b/src/gui/text/qfontengine_p.h
index 780104bc37..5282a4033e 100644
--- a/src/gui/text/qfontengine_p.h
+++ b/src/gui/text/qfontengine_p.h
@@ -214,8 +214,8 @@ public:
virtual QFixed underlinePosition() const;
virtual qreal maxCharWidth() const = 0;
- virtual qreal minLeftBearing() const { return qreal(); }
- virtual qreal minRightBearing() const { return qreal(); }
+ virtual qreal minLeftBearing() const;
+ virtual qreal minRightBearing() const;
virtual void getGlyphBearings(glyph_t glyph, qreal *leftBearing = 0, qreal *rightBearing = 0);
@@ -323,6 +323,10 @@ private:
private:
QVariant m_userData;
+
+ mutable qreal m_minLeftBearing;
+ mutable qreal m_minRightBearing;
+
};
Q_DECLARE_OPERATORS_FOR_FLAGS(QFontEngine::ShaperFlags)
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index d2b39f274c..160daa0cfd 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -107,6 +107,22 @@ struct Q_GUI_EXPORT glyph_metrics_t
glyph_metrics_t transformed(const QTransform &xform) const;
inline bool isValid() const {return x != 100000 && y != 100000;}
+
+ inline QFixed leftBearing() const
+ {
+ if (!isValid())
+ return QFixed();
+
+ return x;
+ }
+
+ inline QFixed rightBearing() const
+ {
+ if (!isValid())
+ return QFixed();
+
+ return xoff - x - width;
+ }
};
Q_DECLARE_TYPEINFO(glyph_metrics_t, Q_PRIMITIVE_TYPE);
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index 0c729c74d1..d68a59fae3 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -1966,9 +1966,16 @@ void QTextLine::layout_helper(int maxGlyphs)
// end up breaking due to the current glyph being too wide.
QFixed previousRightBearing = lbh.rightBearing;
- // We ignore the right bearing if the minimum negative bearing is too little to
- // expand the text beyond the edge.
- if (lbh.calculateNewWidth(line) - lbh.minimumRightBearing > line.width)
+ // We skip calculating the right bearing if the minimum negative bearing is too
+ // small to possibly expand the text beyond the edge. Note that this optimization
+ // will in some cases fail, as the minimum right bearing reported by the font
+ // engine may not cover all the glyphs in the font. The result is that we think
+ // we don't need to break at the current glyph (because the right bearing is 0),
+ // and when we then end up breaking on the next glyph we compute the right bearing
+ // and end up with a line width that is slightly larger width than what was requested.
+ // Unfortunately we can't remove this optimization as it will slow down text
+ // layouting significantly, so we accept the slight correctnes issue.
+ if ((lbh.calculateNewWidth(line) + qAbs(lbh.minimumRightBearing)) > line.width)
lbh.calculateRightBearing();
if (lbh.checkFullOtherwiseExtend(line)) {
diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
index 7e1dfd9275..732aead62a 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
@@ -361,16 +361,6 @@ qreal QCoreTextFontEngine::maxCharWidth() const
return bb.xoff.toReal();
}
-qreal QCoreTextFontEngine::minLeftBearing() const
-{
- return 0;
-}
-
-qreal QCoreTextFontEngine::minRightBearing() const
-{
- return 0;
-}
-
void QCoreTextFontEngine::draw(CGContextRef ctx, qreal x, qreal y, const QTextItemInt &ti, int paintDeviceHeight)
{
QVarLengthArray<QFixedPoint> positions;
diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
index f8ec1d326f..1c33ae7d84 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
@@ -96,8 +96,6 @@ public:
QImage alphaRGBMapForGlyph(glyph_t, QFixed subPixelPosition, const QTransform &t) Q_DECL_OVERRIDE;
glyph_metrics_t alphaMapBoundingBox(glyph_t glyph, QFixed, const QTransform &matrix, GlyphFormat) Q_DECL_OVERRIDE;
QImage bitmapForGlyph(glyph_t, QFixed subPixelPosition, const QTransform &t) Q_DECL_OVERRIDE;
- qreal minRightBearing() const Q_DECL_OVERRIDE;
- qreal minLeftBearing() const Q_DECL_OVERRIDE;
QFixed emSquareSize() const Q_DECL_OVERRIDE;
bool supportsTransformation(const QTransform &transform) const Q_DECL_OVERRIDE;
diff --git a/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp b/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
index 18da61925d..de0c2d6dbe 100644
--- a/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
+++ b/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
@@ -1985,7 +1985,12 @@ void tst_QTextLayout::textWidthVsWIdth()
"./libs -I/home/ettrich/dev/creator/tools -I../../plugins -I../../shared/scriptwrapper -I../../libs/3rdparty/botan/build -Idialogs -Iactionmanager -Ieditorma"
"nager -Iprogressmanager -Iscriptmanager -I.moc/debug-shared -I.uic -o .obj/debug-shared/sidebar.o sidebar.cpp"));
- // textWidth includes right bearing, but it should never be LARGER than width if there is space for at least one character
+ // The naturalTextWidth includes right bearing, but should never be LARGER than line width if
+ // there is space for at least one character. Unfortunately that assumption may not hold if the
+ // font engine fails to report an accurate minimum right bearing for the font, eg. when the
+ // minimum right bearing reported by the font engine doesn't cover all the glyphs in the font.
+ // The result is that this test may fail in some cases. We should fix this by running the test
+ // with a font that we know have no suprising right bearings. See qtextlayout.cpp for details.
for (int width = 100; width < 1000; ++width) {
layout.beginLayout();
QTextLine line = layout.createLine();
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-08 15:52:58 +0000