Fix possible endless loop when stroking curves

The bezier shifting algorithm compared coordinates exactly, and so could end up in an endless loop when values were at the edge of the number resolution. Fix by using fuzzy comparison instead. Fixes: QTBUG-75522 Change-Id: I61346edbd87389f66965a906ac337fc1f5300e5c Reviewed-by: Robert Loehning <[email protected]> Reviewed-by: Allan Sandfeld Jensen <[email protected]>
fwcd · May 8, 2019 · 95fa35f · 95fa35f
1 parent 19d13f8
commit 95fa35f
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/src/gui/painting/qbezier.cpp b/src/gui/painting/qbezier.cpp
@@ -261,9 +261,9 @@ static ShiftResult good_offset(const QBezier *b1, const QBezier *b2, qreal offse
 static ShiftResult shift(const QBezier *orig, QBezier *shifted, qreal offset, qreal threshold)
 {
     int map[4];
-    bool p1_p2_equal = (orig->x1 == orig->x2 && orig->y1 == orig->y2);
-    bool p2_p3_equal = (orig->x2 == orig->x3 && orig->y2 == orig->y3);
-    bool p3_p4_equal = (orig->x3 == orig->x4 && orig->y3 == orig->y4);
+    bool p1_p2_equal = qFuzzyCompare(orig->x1, orig->x2) && qFuzzyCompare(orig->y1, orig->y2);
+    bool p2_p3_equal = qFuzzyCompare(orig->x2, orig->x3) && qFuzzyCompare(orig->y2, orig->y3);
+    bool p3_p4_equal = qFuzzyCompare(orig->x3, orig->x4) && qFuzzyCompare(orig->y3, orig->y4);
 
     QPointF points[4];
     int np = 0;