[cairo-commit] src/cairo-polygon.c

[Chris Wilson]

 src/cairo-polygon.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

New commits:
commit ea16302e45ced56e6f12b8520e9f530e1ffc68c4
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Fri Feb 8 13:22:01 2013 +0000

    polygon: Avoid computing the unused intersection coordinates
    
    If we only ignore the result of the computed boundary intersection,
    because the edge is inside that boundary, then we can simply forgo the
    calculation.
    
    Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

diff --git a/src/cairo-polygon.c b/src/cairo-polygon.c
index 4c5861d..b0424f6 100644
--- a/src/cairo-polygon.c
+++ b/src/cairo-polygon.c
@@ -390,11 +390,6 @@ _add_clipped_edge (cairo_polygon_t *polygon,
 	    cairo_fixed_t left_y, right_y;
 	    cairo_bool_t top_left_to_bottom_right;
 
-	    left_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
-							       limits->p1.x);
-	    right_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
-								limits->p2.x);
-
 	    /*
 	     * The edge intersects the lines corresponding to the left
 	     * and right sides of the limit box at left_y and right_y,
@@ -425,6 +420,8 @@ _add_clipped_edge (cairo_polygon_t *polygon,
 		if (pleft >= limits->p1.x) {
 		    left_y = top_y;
 		} else {
+		    left_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
+								       limits->p1.x);
 		    if (_cairo_edge_compute_intersection_x_for_y (p1, p2, left_y) < limits->p1.x)
 			left_y++;
 		}
@@ -440,6 +437,8 @@ _add_clipped_edge (cairo_polygon_t *polygon,
 		if (pright <= limits->p2.x) {
 		    right_y = bot_y;
 		} else {
+		    right_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
+									limits->p2.x);
 		    if (_cairo_edge_compute_intersection_x_for_y (p1, p2, right_y) > limits->p2.x)
 			right_y--;
 		}
@@ -455,6 +454,8 @@ _add_clipped_edge (cairo_polygon_t *polygon,
 		if (pright <= limits->p2.x) {
 		    right_y = top_y;
 		} else {
+		    right_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
+									limits->p2.x);
 		    if (_cairo_edge_compute_intersection_x_for_y (p1, p2, right_y) > limits->p2.x)
 			right_y++;
 		}
@@ -470,6 +471,8 @@ _add_clipped_edge (cairo_polygon_t *polygon,
 		if (pleft >= limits->p1.x) {
 		    left_y = bot_y;
 		} else {
+		    left_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
+								       limits->p1.x);
 		    if (_cairo_edge_compute_intersection_x_for_y (p1, p2, left_y) < limits->p1.x)
 			left_y--;
 		}