Fix boundingBox for raster engine with synthesized italic fonts

We need to account for the extra right side bearing caused by
text transform for synthesized italic.

Task-number: QTBUG-14803
Reviewed-by: Eskil

1 files changed, 8 insertions, 5 deletions

diff --git a/src/gui/text/qfontengine_coretext.mm b/src/gui/text/qfontengine_coretext.mm
index dcc8329612..2ae60b15f4 100644
--- a/src/gui/text/qfontengine_coretext.mm
+++ b/src/gui/text/qfontengine_coretext.mm
@@ -50,6 +50,8 @@
 
 QT_BEGIN_NAMESPACE
 
+static float SYNTHETIC_ITALIC_SKEW = tanf(14 * acosf(0) / 90);
+
 QCoreTextFontEngineMulti::QCoreTextFontEngineMulti(const QCFString &name, const QFontDef &fontDef, bool kerning)
     : QFontEngineMulti(0)
 {
@@ -396,6 +398,9 @@ glyph_metrics_t QCoreTextFontEngine::boundingBox(glyph_t glyph)
     glyph_metrics_t ret;
     CGGlyph g = glyph;
     CGRect rect = CTFontGetBoundingRectsForGlyphs(ctfont, kCTFontHorizontalOrientation, &g, 0, 1);
+    if (synthesisFlags & QFontEngine::SynthesizedItalic) {
+        rect.size.width += rect.size.height * SYNTHETIC_ITALIC_SKEW;
+    }
     ret.width = QFixed::fromReal(rect.size.width);
     ret.height = QFixed::fromReal(rect.size.height);
     ret.x = QFixed::fromReal(rect.origin.x);
@@ -487,7 +492,7 @@ void QCoreTextFontEngine::draw(CGContextRef ctx, qreal x, qreal y, const QTextIt
     CGAffineTransformConcat(cgMatrix, oldTextMatrix);
 
     if (synthesisFlags & QFontEngine::SynthesizedItalic)
-        cgMatrix = CGAffineTransformConcat(cgMatrix, CGAffineTransformMake(1, 0, -tanf(14 * acosf(0) / 90), 1, 0, 0));
+        cgMatrix = CGAffineTransformConcat(cgMatrix, CGAffineTransformMake(1, 0, -SYNTHETIC_ITALIC_SKEW, 1, 0, 0));
 
     cgMatrix = CGAffineTransformConcat(cgMatrix, transform);
 
@@ -570,13 +575,11 @@ static void convertCGPathToQPainterPath(void *info, const CGPathElement *element
 void QCoreTextFontEngine::addGlyphsToPath(glyph_t *glyphs, QFixedPoint *positions, int nGlyphs,
                                           QPainterPath *path, QTextItem::RenderFlags)
 {
-
     CGAffineTransform cgMatrix = CGAffineTransformIdentity;
     cgMatrix = CGAffineTransformScale(cgMatrix, 1, -1);
 
     if (synthesisFlags & QFontEngine::SynthesizedItalic)
-        cgMatrix = CGAffineTransformConcat(cgMatrix, CGAffineTransformMake(1, 0, -tanf(14 * acosf(0) / 90), 1, 0, 0));
-
+        cgMatrix = CGAffineTransformConcat(cgMatrix, CGAffineTransformMake(1, 0, -SYNTHETIC_ITALIC_SKEW, 1, 0, 0));
 
     for (int i = 0; i < nGlyphs; ++i) {
         QCFType<CGPathRef> cgpath = CTFontCreatePathForGlyph(ctfont, glyphs[i], &cgMatrix);
@@ -616,7 +619,7 @@ QImage QCoreTextFontEngine::imageForGlyph(glyph_t glyph, QFixed subPixelPosition
     CGAffineTransformConcat(cgMatrix, oldTextMatrix);
 
     if (synthesisFlags & QFontEngine::SynthesizedItalic)
-        cgMatrix = CGAffineTransformConcat(cgMatrix, CGAffineTransformMake(1, 0, tanf(14 * acosf(0) / 90), 1, 0, 0));
+        cgMatrix = CGAffineTransformConcat(cgMatrix, CGAffineTransformMake(1, 0, SYNTHETIC_ITALIC_SKEW, 1, 0, 0));
 
     cgMatrix = CGAffineTransformConcat(cgMatrix, transform);