Blinking cursors are 2 pixels wide on Mac OS X/Cocoa.

Blinking cursors drawn in positions other than zero, can become 2 pixel
wide. This is caused by a rendering bug in the paint engine used by
Cocoa. If a fillRect() is called in a nox pixel boundary this engine
draws them 2 pixels wide instead of one. So make sure this is always on
a pixel boundary.

Task-number: QTBUG-8100
Reviewed-by: Trond

1 files changed, 5 insertions, 1 deletions

diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index 26c7c1e..af91603 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -1331,7 +1331,7 @@ void QTextLayout::drawCursor(QPainter *p, const QPointF &pos, int cursorPosition
     QTextLine l(line, d);
     const QScriptLine &sl = d->lines[line];
 
-    const qreal x = position.x() + l.cursorToX(cursorPosition);
+    qreal x = position.x() + l.cursorToX(cursorPosition);
 
     int itm = d->findItem(cursorPosition - 1);
     QFixed base = sl.base();
@@ -1350,6 +1350,10 @@ void QTextLayout::drawCursor(QPainter *p, const QPointF &pos, int cursorPosition
                               && (p->transform().type() > QTransform::TxTranslate);
     if (toggleAntialiasing)
         p->setRenderHint(QPainter::Antialiasing);
+#if defined(QT_MAC_USE_COCOA)
+    // Always draw the cursor aligned to pixel boundary.
+    x = qRound(x);
+#endif
     p->fillRect(QRectF(x, y, qreal(width), (base + descent + 1).toReal()), p->pen().brush());
     if (toggleAntialiasing)
         p->setRenderHint(QPainter::Antialiasing, false);