Fix crash for borderimage with negative borders

Replace negative margin values with 0. Test case:
qtdeclarative/tests/manual/scenegraph_lancelot/data/borderimages/borderimage_rotated_unsmoothed_negative_borders.qml

Change-Id: I53d143fd079cbaa5e6c8080ada81720f8b1b598b
Reviewed-by: Andy Nichols <andy.nichols@theqtcompany.com>
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@theqtcompany.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/src/plugins/scenegraph/softwarecontext/imagenode.cpp b/src/plugins/scenegraph/softwarecontext/imagenode.cpp
index 3146830172..0ca579db5b 100644
--- a/src/plugins/scenegraph/softwarecontext/imagenode.cpp
+++ b/src/plugins/scenegraph/softwarecontext/imagenode.cpp
@@ -28,8 +28,13 @@
 
 namespace SoftwareContext {
 
-void qDrawBorderPixmap(QPainter *painter, const QRect &targetRect, const QMargins &targetMargins,
-                       const QPixmap &pixmap, const QRect &sourceRect,const QMargins &sourceMargins,
+static inline QMargins normalizedMargins(const QMargins &m)
+{
+    return QMargins(qMax(m.left(), 0), qMax(m.top(), 0), qMax(m.right(), 0), qMax(m.bottom(), 0));
+}
+
+void qDrawBorderPixmap(QPainter *painter, const QRect &targetRect, const QMargins &targetMarginsIn,
+                       const QPixmap &pixmap, const QRect &sourceRect, const QMargins &sourceMarginsIn,
                        const QTileRules &rules, QDrawBorderPixmap::DrawingHints hints)
 {
     QPainter::PixmapFragment d;
@@ -39,6 +44,9 @@ void qDrawBorderPixmap(QPainter *painter, const QRect &targetRect, const QMargin
     QPixmapFragmentsArray opaqueData;
     QPixmapFragmentsArray translucentData;
 
+    QMargins sourceMargins = normalizedMargins(sourceMarginsIn);
+    QMargins targetMargins = normalizedMargins(targetMarginsIn);
+
     // source center
     const int sourceCenterTop = sourceRect.top() + sourceMargins.top();
     const int sourceCenterLeft = sourceRect.left() + sourceMargins.left();