Fix bidi PDF mark support in Core Text shaper

When Core Text shaping a string like LRE ... PDF, it won't leave
a zero width glyph for the PDF mark, it is not consistent with
HarfBuzz and will cause issues in our text engine (the last glyph
of the string will be considered as a ligature). This hack
appended such a zero width glyph to fix that.

Reviewed-by: Eskil

1 files changed, 18 insertions, 0 deletions

diff --git a/src/gui/text/qfontengine_mac.mm b/src/gui/text/qfontengine_mac.mm
index 51e18ec..3c6f3b2 100644
--- a/src/gui/text/qfontengine_mac.mm
+++ b/src/gui/text/qfontengine_mac.mm
@@ -252,6 +252,11 @@ bool QCoreTextFontEngineMulti::stringToCMap(const QChar *str, int len, QGlyphLay
             continue;
 
         Q_ASSERT((CTRunGetStatus(run) & kCTRunStatusRightToLeft) == rtl);
+        CFRange stringRange = CTRunGetStringRange(run);
+        UniChar endGlyph = CFStringGetCharacterAtIndex(cfstring, stringRange.location + stringRange.length - 1);
+        bool endWithPDF = QChar::direction(endGlyph) == QChar::DirPDF;
+        if (endWithPDF)
+            glyphCount++;
 
         if (!outOBounds && outGlyphs + glyphCount - initialGlyph > *nglyphs) {
             outOBounds = true;
@@ -264,6 +269,9 @@ bool QCoreTextFontEngineMulti::stringToCMap(const QChar *str, int len, QGlyphLay
             CTFontRef runFont = static_cast<CTFontRef>(CFDictionaryGetValue(runAttribs, NSFontAttributeName));
             const uint fontIndex = (fontIndexForFont(runFont) << 24);
             //NSLog(@"Run Font Name = %@", CTFontCopyFamilyName(runFont));
+            if (endWithPDF)
+                glyphCount--;
+
             QVarLengthArray<CGGlyph, 512> cgglyphs(0);
             const CGGlyph *tmpGlyphs = CTRunGetGlyphsPtr(run);
             if (!tmpGlyphs) {
@@ -331,6 +339,16 @@ bool QCoreTextFontEngineMulti::stringToCMap(const QChar *str, int len, QGlyphLay
                     (fontDef.styleStrategy & QFont::ForceIntegerMetrics)
                     ? QFixed::fromReal(lastGlyphAdvance.width).round()
                     : QFixed::fromReal(lastGlyphAdvance.width);
+
+            if (endWithPDF) {
+                logClusters[stringRange.location + stringRange.length - 1] = glyphCount;
+                outGlyphs[glyphCount] = 0xFFFF;
+                outAdvances_x[glyphCount] = 0;
+                outAdvances_y[glyphCount] = 0;
+                outAttributes[glyphCount].clusterStart = true;
+                outAttributes[glyphCount].dontPrint = true;
+                glyphCount++;
+            }
         }
         outGlyphs += glyphCount;
         outAttributes += glyphCount;