diff --git a/src/gui/painting/qstroker_p.h b/src/gui/painting/qstroker_p.h
index f967c091df2..d3765bbd29b 100644
--- a/src/gui/painting/qstroker_p.h
+++ b/src/gui/painting/qstroker_p.h
@@ -201,7 +201,7 @@ public:
     QStroker();
     ~QStroker();
 
-    void setStrokeWidth(qfixed width) { m_strokeWidth = width; m_curveThreshold = width >= 1 ? 1.0/width : 0.5;}
+    void setStrokeWidth(qfixed width) { m_strokeWidth = width; m_curveThreshold = qt_real_to_fixed(width > 4 ? 1.0/width : 0.25); }
     qfixed strokeWidth() const { return m_strokeWidth; }
 
     void setCapStyle(Qt::PenCapStyle capStyle) { m_capStyle = joinModeForCap(capStyle); }
diff --git a/tests/auto/other/lancelot/scripts/arcs2.qps b/tests/auto/other/lancelot/scripts/arcs2.qps
index 411ff080145..a2739a8c976 100644
--- a/tests/auto/other/lancelot/scripts/arcs2.qps
+++ b/tests/auto/other/lancelot/scripts/arcs2.qps
@@ -45,3 +45,10 @@ drawArc 100 350 300 300 5440 5760
 drawArc 100 350 300 300 5600 5760
 setPen white
 drawArc 100 350 300 300 0 5760
+
+translate 400 300
+setRenderHint Antialiasing true
+setPen blue 40
+drawArc 100 100 200 200 0 4320
+setPen red 40
+drawArc 60 60 280 280 0 4320