[fallback] Include implicit closes in the check for rectilinear paths

Fixes test/implicit-close

By forgetting the implicit-close when checking for rectilinear paths, we
tried to feed the triangle (and other diagclose) into the specialised
rectilinear tesselators which completely mishandled that final edge.

2 files changed, 18 insertions, 2 deletions

diff --git a/src/cairo-path-fixed-private.h b/src/cairo-path-fixed-private.h
index f25a45e2..ce35c9ef 100644
--- a/src/cairo-path-fixed-private.h
+++ b/src/cairo-path-fixed-private.h
@@ -136,6 +136,20 @@ _cairo_path_fixed_fill_is_empty (const cairo_path_fixed_t *path)
 }
 
 static inline cairo_bool_t
+_cairo_path_fixed_is_rectilinear_fill (const cairo_path_fixed_t *path)
+{
+    if (! path->is_rectilinear)
+	return FALSE;
+
+    if (! path->has_current_point)
+	return TRUE;
+
+    /* check whether the implicit close preserves the rectilinear property */
+    return path->current_point.x == path->last_move_point.x ||
+	   path->current_point.y == path->last_move_point.y;
+}
+
+static inline cairo_bool_t
 _cairo_path_fixed_maybe_fill_region (const cairo_path_fixed_t *path)
 {
 #if WATCH_PATH
diff --git a/src/cairo-surface-fallback.c b/src/cairo-surface-fallback.c
index a5a529ca..8fa7fa98 100644
--- a/src/cairo-surface-fallback.c
+++ b/src/cairo-surface-fallback.c
@@ -1233,6 +1233,7 @@ _cairo_surface_fallback_fill (cairo_surface_t		*surface,
     int num_boxes = ARRAY_LENGTH (boxes_stack);
     cairo_rectangle_int_t extents;
     cairo_bool_t is_bounded;
+    cairo_bool_t is_rectilinear;
     cairo_status_t status;
 
     is_bounded = _cairo_surface_get_extents (surface, &extents);
@@ -1286,7 +1287,8 @@ _cairo_surface_fallback_fill (cairo_surface_t		*surface,
     if (path->is_empty_fill)
 	goto DO_TRAPS;
 
-    if (path->is_rectilinear) {
+    is_rectilinear = _cairo_path_fixed_is_rectilinear_fill (path);
+    if (is_rectilinear) {
 	status = _cairo_path_fixed_fill_rectilinear_to_traps (path,
 							      fill_rule,
 							      &traps);
@@ -1312,7 +1314,7 @@ _cairo_surface_fallback_fill (cairo_surface_t		*surface,
 	    goto CLEANUP;
     }
 
-    if (path->is_rectilinear) {
+    if (is_rectilinear) {
 	status = _cairo_bentley_ottmann_tessellate_rectilinear_polygon (&traps,
 									&polygon,
 									fill_rule);