[tessellate] Rectangular special case

Add an even simpler sweep-line tessellator for rectangular trapezoids (as
produced by the rectilinear stoker and box filler).

This is so simple it even outperforms pixman's region validation code for the
purposes of path-to-region conversion.

1 files changed, 14 insertions, 26 deletions

diff --git a/src/cairo-path-fill.c b/src/cairo-path-fill.c
index 3daf24614..870a987fd 100644
--- a/src/cairo-path-fill.c
+++ b/src/cairo-path-fill.c
@@ -356,6 +356,9 @@ _cairo_path_fixed_fill_rectilinear_to_traps (const cairo_path_fixed_t *path,
     cairo_box_t box;
     cairo_status_t status;
 
+    traps->is_rectilinear = TRUE;
+    traps->is_rectangular = TRUE;
+
     if (_cairo_path_fixed_is_box (path, &box)) {
 	if (box.p1.x > box.p2.x) {
 	    cairo_fixed_t t;
@@ -374,24 +377,11 @@ _cairo_path_fixed_fill_rectilinear_to_traps (const cairo_path_fixed_t *path,
 	}
 
 	return _cairo_traps_tessellate_rectangle (traps, &box.p1, &box.p2);
-    } else if (fill_rule == CAIRO_FILL_RULE_WINDING) {
+    } else {
 	cairo_path_fixed_iter_t iter;
-	int last_cw = -1;
 
 	_cairo_path_fixed_iter_init (&iter, path);
 	while (_cairo_path_fixed_iter_is_fill_box (&iter, &box)) {
-	    int cw = 0;
-
-	    if (box.p1.x > box.p2.x) {
-		cairo_fixed_t t;
-
-		t = box.p1.x;
-		box.p1.x = box.p2.x;
-		box.p2.x = t;
-
-		cw = ! cw;
-	    }
-
 	    if (box.p1.y > box.p2.y) {
 		cairo_fixed_t t;
 
@@ -399,25 +389,23 @@ _cairo_path_fixed_fill_rectilinear_to_traps (const cairo_path_fixed_t *path,
 		box.p1.y = box.p2.y;
 		box.p2.y = t;
 
-		cw = ! cw;
+		t = box.p1.x;
+		box.p1.x = box.p2.x;
+		box.p2.x = t;
 	    }
 
-	    if (last_cw < 0)
-		last_cw = cw;
-	    else if (last_cw != cw)
-		goto out;
-
 	    status = _cairo_traps_tessellate_rectangle (traps,
 							&box.p1, &box.p2);
-	    if (unlikely (status))
+	    if (unlikely (status)) {
+		_cairo_traps_clear (traps);
 		return status;
+	    }
 	}
 
 	if (_cairo_path_fixed_iter_at_end (&iter))
-	    return CAIRO_STATUS_SUCCESS;
-    }
+	    return _cairo_bentley_ottmann_tessellate_rectangular_traps (traps, fill_rule);
 
-  out:
-    _cairo_traps_clear (traps);
-    return CAIRO_INT_STATUS_UNSUPPORTED;
+	_cairo_traps_clear (traps);
+	return CAIRO_INT_STATUS_UNSUPPORTED;
+    }
 }