[cairo-commit] cairo/src cairo-hull.c,1.9,1.9.2.1

[Bertram Felgenhauer]

Committed by: inte

Update of /cvs/cairo/cairo/src
In directory gabe:/tmp/cvs-serv18751/src

Modified Files:
      Tag: BRANCH_1_0
	cairo-hull.c 
Log Message:
2005-09-30  Bertram Felgenhauer  <int-e at gmx.de>

	reviewed by: cworth
	
	* src/cairo-hull.c (_cairo_hull_create),
	(_cairo_hull_vertex_compare): Using a pointer comparison as the
	fallback total order was wrong - these pointers are not stable.
	So we introduce our own total order instead. 


Index: cairo-hull.c
===================================================================
RCS file: /cvs/cairo/cairo/src/cairo-hull.c,v
retrieving revision 1.9
retrieving revision 1.9.2.1
diff -u -d -r1.9 -r1.9.2.1
--- cairo-hull.c	21 Aug 2005 18:41:44 -0000	1.9
+++ cairo-hull.c	30 Sep 2005 00:28:54 -0000	1.9.2.1
@@ -41,6 +41,7 @@
     cairo_point_t point;
     cairo_slope_t slope;
     int discard;
+    int id;
 } cairo_hull_t;
 
 static cairo_hull_t *
@@ -70,10 +71,13 @@
 	_cairo_slope_init (&hull[i].slope, &hull[0].point, &hull[i].point);
 
 	/* Discard all points coincident with the extremal point */
-	if (i != 0 && hull[i].slope.dx == 0 && hull[i].slope.dy == 0)
+	if (i != 0 && hull[i].slope.dx == 0 && hull[i].slope.dy == 0) {
 	    hull[i].discard = 1;
-	else
+            hull[i].id = -i;
+        } else {
 	    hull[i].discard = 0;
+            hull[i].id = i;
+        }
     }
 
     return hull;
@@ -98,11 +102,11 @@
 	b_dist = ((cairo_fixed_48_16_t) b->slope.dx * b->slope.dx +
 		  (cairo_fixed_48_16_t) b->slope.dy * b->slope.dy);
 	/*
-	 * Use pointer comparison for coincident points to ensure
+	 * Use the point's ids to ensure a total ordering.
 	 * a well-defined ordering, and avoid setting discard on
-	 * both points.
+	 * both points.          
 	 */
-	if (a_dist < b_dist || (a_dist == b_dist && a < b)) {
+	if (a_dist < b_dist || (a_dist == b_dist && a->id < b->id)) {
 	    a->discard = 1;
 	    ret = -1;
 	} else {