Fixed segmentation fault caused by empty clip.

Make sure not to use the broken QRect constructor, and do an early check
on whether the clip rect is empty in QRasterizer::rasterizeLine().

Task-number: 254105
Reviewed-by: Trond

3 files changed, 21 insertions, 2 deletions

diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index 743c4b8..84af880 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -3956,7 +3956,7 @@ void QRasterPaintEnginePrivate::initializeRasterizer(QSpanData *data)
     const QClipData *c = clip();
     if (c) {
         const QRect r(QPoint(c->xmin, c->ymin),
-                      QPoint(c->xmax, c->ymax));
+                      QSize(c->xmax - c->xmin, c->ymax - c->ymin));
         clipRect = clipRect.intersected(r);
         blend = data->blend;
     } else {
diff --git a/src/gui/painting/qrasterizer.cpp b/src/gui/painting/qrasterizer.cpp
index 629b38e..58e4b4e 100644
--- a/src/gui/painting/qrasterizer.cpp
+++ b/src/gui/painting/qrasterizer.cpp
@@ -703,7 +703,7 @@ static inline qreal qRoundF(qreal v)
 
 void QRasterizer::rasterizeLine(const QPointF &a, const QPointF &b, qreal width, bool squareCap)
 {
-    if (a == b || width == 0)
+    if (a == b || width == 0 || d->clipRect.isEmpty())
         return;
 
     QPointF pa = a;
diff --git a/tests/auto/qpainter/tst_qpainter.cpp b/tests/auto/qpainter/tst_qpainter.cpp
index dcf9a04..cb532ce 100644
--- a/tests/auto/qpainter/tst_qpainter.cpp
+++ b/tests/auto/qpainter/tst_qpainter.cpp
@@ -227,6 +227,7 @@ private slots:
     void extendedBlendModes();
 
     void zeroOpacity();
+    void emptyClip();
 
 private:
     void fillData();
@@ -4194,5 +4195,23 @@ void tst_QPainter::zeroOpacity()
     QCOMPARE(target.pixel(0, 0), 0xff000000);
 }
 
+void tst_QPainter::emptyClip()
+{
+    QImage img(64, 64, QImage::Format_ARGB32_Premultiplied);
+    QPainter p(&img);
+    p.setRenderHints(QPainter::Antialiasing);
+    p.setClipRect(0, 32, 64, 0);
+    p.fillRect(0, 0, 64, 64, Qt::white);
+
+    QPainterPath path;
+    path.lineTo(64, 0);
+    path.lineTo(64, 64);
+    path.lineTo(40, 64);
+    path.lineTo(40, 80);
+    path.lineTo(0, 80);
+
+    p.fillPath(path, Qt::green);
+}
+
 QTEST_MAIN(tst_QPainter)
 #include "tst_qpainter.moc"