SVN commit 731544 by fredrik:

According to the spec, lineTo(), quadraticCurveTo(), bezierCurveTo() and
arcTo() should do nothing when the path is empty. Unfortunately a
QPainterPath always contains an initial MoveTo element, so we have no
reliable way of checking if the path is empty.

As a workaround, call moveTo(-INT_MAX, -INT_MAX) in beginPath(), and check
the current position for this value in all functions that are supposed to
do nothing when the path is empty. This commit doesn't change arcTo() and
arc(), because they will be replaced with new implementations shortly.


 M  +13 -3     html_canvasimpl.cpp  


--- trunk/KDE/kdelibs/khtml/html/html_canvasimpl.cpp #731543:731544
@@ -886,6 +886,13 @@
 {
     path = QPainterPath();
     path.setFillRule(Qt::WindingFill);
+
+    // Unfortunately QPainterPath always contains an intial MoveTo element to (0, 0),
+    // so we have no reliable way to check if the path is empty. We'll therefor
+    // insert a MoveTo to (-INT_MAX, -INT_MAX) each time the path is reset, and check
+    // the current position for this value in all functions that are supposed to do
+    // nothing when the path is empty.
+    path.moveTo(-INT_MAX, -INT_MAX);
 }
 
 void CanvasContext2DImpl::closePath()
@@ -900,17 +907,20 @@
 
 void CanvasContext2DImpl::lineTo(float x, float y)
 {
-    path.lineTo(x, y);
+    if (path.currentPosition() != QPointF(-INT_MAX, -INT_MAX))
+        path.lineTo(x, y);
 }
 
 void CanvasContext2DImpl::quadraticCurveTo(float cpx, float cpy, float x, float y)
 {
-    path.quadTo(cpx, cpy, x, y);
+    if (path.currentPosition() != QPointF(-INT_MAX, -INT_MAX))
+        path.quadTo(cpx, cpy, x, y);
 }
 
 void CanvasContext2DImpl::bezierCurveTo(float cp1x, float cp1y, float cp2x, float cp2y, float x, float y)
 {
-    path.cubicTo(cp1x, cp1y, cp2x, cp2y, x, y);
+    if (path.currentPosition() != QPointF(-INT_MAX, -INT_MAX))
+        path.cubicTo(cp1x, cp1y, cp2x, cp2y, x, y);
 }
 
 void CanvasContext2DImpl::rect(float x, float y, float w, float h, int& exceptionCode)