[path] Return the fixed-point bounds of the path

When analysing the stroke extents, we need the original fixed-point
extents so that we do not incur an OBO when we round-to-integer a second
time. We also need a more accurate estimate than simply using the control
points of the curve, so pass in tolerance and decompose until someone
discovers a cheaper algorithm to determine the precise aligned bounding
box of a bezier curve.

1 files changed, 14 insertions, 11 deletions

diff --git a/src/cairo-clip.c b/src/cairo-clip.c
index c679e9fb..cd369242 100644
--- a/src/cairo-clip.c
+++ b/src/cairo-clip.c
@@ -143,11 +143,13 @@ _cairo_clip_path_intersect_to_rectangle (cairo_clip_path_t       *clip_path,
 				         cairo_rectangle_int_t   *rectangle)
 {
     while (clip_path) {
-        cairo_rectangle_int_t extents;
+        cairo_box_t extents;
 
-	_cairo_path_fixed_approximate_extents (&clip_path->path, &extents);
+	_cairo_path_fixed_approximate_extents (&clip_path->path,
+					       clip_path->tolerance,
+					       &extents);
 
-        if (! _cairo_rectangle_intersect (rectangle, &extents))
+        if (! _cairo_rectangle_intersect_box (rectangle, &extents))
 	    return CAIRO_STATUS_SUCCESS;
 
         clip_path = clip_path->prev;
@@ -568,20 +570,21 @@ _cairo_clip_intersect_mask_using_spans (cairo_clip_t       *clip,
 	goto BAIL;
     }
 
+    status = _cairo_surface_get_extents (target, &surface_rect);
+    if (status)
+	goto BAIL;
+
     /* We'll create a new surface the size of the intersection of the
      * old mask surface and the extents of the new clip path. */
     {
-	cairo_rectangle_int_t target_rect;
+	cairo_box_t extents;
 
-	_cairo_path_fixed_approximate_extents (path, &surface_rect);
-
-	if (clip->surface != NULL &&
-	    !_cairo_rectangle_intersect (&surface_rect, &clip->surface_rect))
+	_cairo_path_fixed_approximate_extents (path, tolerance, &extents);
+	if (! _cairo_rectangle_intersect_box (&surface_rect, &extents))
 	    goto SUCCESS;
 
-	status = _cairo_surface_get_extents (target, &target_rect);
-	if (status != CAIRO_STATUS_SUCCESS &&
-	    !_cairo_rectangle_intersect (&surface_rect, &target_rect))
+	if (clip->surface != NULL &&
+	    ! _cairo_rectangle_intersect (&surface_rect, &clip->surface_rect))
 	    goto SUCCESS;
     }