Correct last right bearing in boundingBox(glyphs)

Commit 07880542ecc479807c23c5646d263135240822ff introduced regression to
QFontMetrics::boundingRect and QTextEngine::boundingBox on FT, XLFD and
QPF font engine. Because on these platforms, rightBearing of the last
glyphs is already removed from the width returned in glyph_metrics_t.
Subtracting that rightBearing twice will cause the resulting boundingBox
smaller than expected.

This patch fix this by removing last right bearing accounting code from
generic QTextEngine::boundingBox, instead, we put it into font engines
that need them: QFontEngineWin, QCoreTextFontEngine, QFontEngineMac,
QFontEngineS60 and QFontEngineQWS. So that the resulting width should be
correct on all platforms without introducing any performance penalties.

Task-number: QTBUG-6854, QTBUG-12950
Reviewed-by: Eskil

1 files changed, 1 insertions, 6 deletions

diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index 8d6dd6c..c30091e 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -1646,7 +1646,6 @@ glyph_metrics_t QTextEngine::boundingBox(int from,  int len) const
 
     for (int i = 0; i < layoutData->items.size(); i++) {
         const QScriptItem *si = layoutData->items.constData() + i;
-        QFontEngine *fe = fontEngine(*si);
 
         int pos = si->position;
         int ilen = length(i);
@@ -1676,6 +1675,7 @@ glyph_metrics_t QTextEngine::boundingBox(int from,  int len) const
                 while (charFrom < ilen && logClusters[charFrom] == glyphStart)
                     charFrom++;
             if (charFrom < ilen) {
+                QFontEngine *fe = fontEngine(*si);
                 glyphStart = logClusters[charFrom];
                 int charEnd = from + len - 1 - pos;
                 if (charEnd >= ilen)
@@ -1694,11 +1694,6 @@ glyph_metrics_t QTextEngine::boundingBox(int from,  int len) const
                     gm.yoff += m.yoff;
                 }
             }
-
-            glyph_t glyph = glyphs.glyphs[logClusters[ilen - 1]];
-            glyph_metrics_t gi = fe->boundingBox(glyph);
-            if (gi.isValid())
-                gm.width -= qRound(gi.xoff - gi.x - gi.width);
         }
     }
     return gm;