[spline] Eliminate intermediate allocations during spline decomposition.

The spline decomposition code allocates and stores points in a temporary
buffer which is immediately consumed by the caller. If the caller supplies
a callback that handles each point computed along the spline, then we can
use the point immediately and avoid the allocation.

1 files changed, 11 insertions, 12 deletions

diff --git a/src/cairo-polygon.c b/src/cairo-polygon.c
index 1392bfa18..95cadc9cc 100644
--- a/src/cairo-polygon.c
+++ b/src/cairo-polygon.c
@@ -84,16 +84,17 @@ _cairo_polygon_grow (cairo_polygon_t *polygon)
     return TRUE;
 }
 
-static void
+void
 _cairo_polygon_add_edge (cairo_polygon_t *polygon,
 			 const cairo_point_t *p1,
-			 const cairo_point_t *p2)
+			 const cairo_point_t *p2,
+			 int		      dir)
 {
     cairo_edge_t *edge;
 
     /* drop horizontal edges */
     if (p1->y == p2->y)
-	goto DONE;
+	return;
 
     if (polygon->num_edges == polygon->edges_size) {
 	if (! _cairo_polygon_grow (polygon))
@@ -104,15 +105,12 @@ _cairo_polygon_add_edge (cairo_polygon_t *polygon,
     if (p1->y < p2->y) {
 	edge->edge.p1 = *p1;
 	edge->edge.p2 = *p2;
-	edge->clockWise = 1;
+	edge->dir = dir;
     } else {
 	edge->edge.p1 = *p2;
 	edge->edge.p2 = *p1;
-	edge->clockWise = 0;
+	edge->dir = -dir;
     }
-
-  DONE:
-    _cairo_polygon_move_to (polygon, p2);
 }
 
 void
@@ -131,9 +129,9 @@ _cairo_polygon_line_to (cairo_polygon_t *polygon,
 			const cairo_point_t *point)
 {
     if (polygon->has_current_point)
-	_cairo_polygon_add_edge (polygon, &polygon->current_point, point);
-    else
-	_cairo_polygon_move_to (polygon, point);
+	_cairo_polygon_add_edge (polygon, &polygon->current_point, point, 1);
+
+    _cairo_polygon_move_to (polygon, point);
 }
 
 void
@@ -142,7 +140,8 @@ _cairo_polygon_close (cairo_polygon_t *polygon)
     if (polygon->has_current_point) {
 	_cairo_polygon_add_edge (polygon,
 				 &polygon->current_point,
-				 &polygon->first_point);
+				 &polygon->first_point,
+				 1);
 
 	polygon->has_current_point = FALSE;
     }