Refix for avoiding huge number of tiny dashes

Previous fix hit too widely so some valid horizontal and vertical
lines were affected; the root problem being that such lines have an
empty control point rect (width or height is 0). Fix by caculating in
the pen width.

Pick-to: 6.2 6.1 5.15
Change-Id: I7a436e873f6d485028f6759d0e2c6456f07eebdc
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/gui/painting/qpaintengineex.cpp b/src/gui/painting/qpaintengineex.cpp
index 22e9a621c3..d85c2a951c 100644
--- a/src/gui/painting/qpaintengineex.cpp
+++ b/src/gui/painting/qpaintengineex.cpp
@@ -415,18 +415,18 @@ void QPaintEngineEx::stroke(const QVectorPath &path, const QPen &inPen)
             clipRect = xf.inverted().mapRect(QRectF(d->exDeviceRect));
         }
         // Check to avoid generating unwieldy amount of dashes that will not be visible anyway
-        QRectF extentRect = cpRect & clipRect;
+        qreal pw = pen.widthF() ? pen.widthF() : 1;
+        QRectF extentRect = cpRect.adjusted(-pw, -pw, pw, pw) & clipRect;
         qreal extent = qMax(extentRect.width(), extentRect.height());
         qreal patternLength = 0;
         const QList<qreal> pattern = pen.dashPattern();
         const int patternSize = qMin(pattern.size(), 32);
         for (int i = 0; i < patternSize; i++)
             patternLength += qMax(pattern.at(i), qreal(0));
-        if (pen.widthF())
-            patternLength *= pen.widthF();
+        patternLength *= pw;
         if (qFuzzyIsNull(patternLength)) {
             pen.setStyle(Qt::NoPen);
-        } else if (qFuzzyIsNull(extent) || extent / patternLength > 10000) {
+        } else if (extent / patternLength > 10000) {
             // approximate stream of tiny dashes with semi-transparent solid line
             pen.setStyle(Qt::SolidLine);
             QColor color(pen.color());