Remove clip handling from generic surface layer.

Handling clip as part of the surface state, as opposed to being part of
the operation state, is cumbersome and a hindrance to providing true proxy
surface support. For example, the clip must be copied from the surface
onto the fallback image, but this was forgotten causing undue hassle in
each backend. Another example is the contortion the meta surface
endures to ensure the clip is correctly recorded. By contrast passing the
clip along with the operation is quite simple and enables us to write
generic handlers for providing surface wrappers. (And in the future, we
should be able to write more esoteric wrappers, e.g. automatic 2x FSAA,
trivially.)

In brief, instead of the surface automatically applying the clip before
calling the backend, the backend can call into a generic helper to apply
clipping. For raster surfaces, clip regions are handled automatically as
part of the composite interface. For vector surfaces, a clip helper is
introduced to replay and callback into an intersect_clip_path() function
as necessary.

Whilst this is not primarily a performance related change (the change
should just move the computation of the clip from the moment it is applied
by the user to the moment it is required by the backend), it is important
to track any potential regression:

ppc:
Speedups
========
image-rgba         evolution-20090607-0    1026085.22 0.18% -> 672972.07 0.77%:  1.52x speedup
▌
image-rgba         evolution-20090618-0    680579.98 0.12% -> 573237.66  0.16%:  1.19x speedup
▎
image-rgba      swfdec-fill-rate-4xaa-0    460296.92 0.36% -> 407464.63  0.42%:  1.13x speedup
▏
image-rgba      swfdec-fill-rate-2xaa-0    128431.95 0.47% -> 115051.86  0.42%:  1.12x speedup
▏
Slowdowns
=========
image-rgba     firefox-periodic-table-0    56837.61 0.78% -> 66055.17    3.20%:  1.09x slowdown
▏

1 files changed, 138 insertions, 63 deletions

diff --git a/src/cairo-path-fixed.c b/src/cairo-path-fixed.c
index 0a550399c..9819353b3 100644
--- a/src/cairo-path-fixed.c
+++ b/src/cairo-path-fixed.c
@@ -96,25 +96,32 @@ _cairo_path_fixed_init (cairo_path_fixed_t *path)
     path->last_move_point = path->current_point;
     path->has_current_point = FALSE;
     path->has_curve_to = FALSE;
-    path->is_region = TRUE;
-    path->is_box = TRUE;
+    path->is_rectilinear = TRUE;
+    path->maybe_fill_region = TRUE;
+    path->is_empty_fill = TRUE;
 }
 
 cairo_status_t
 _cairo_path_fixed_init_copy (cairo_path_fixed_t *path,
-			     cairo_path_fixed_t *other)
+			     const cairo_path_fixed_t *other)
 {
     cairo_path_buf_t *buf, *other_buf;
     unsigned int num_points, num_ops, buf_size;
 
-    _cairo_path_fixed_init (path);
+    VG (VALGRIND_MAKE_MEM_UNDEFINED (path, sizeof (cairo_path_fixed_t)));
+
+    cairo_list_init (&path->buf.base.link);
+
+    path->buf.base.op = path->buf.op;
+    path->buf.base.points = path->buf.points;
 
     path->current_point = other->current_point;
-    path->has_current_point = other->has_current_point;
     path->last_move_point = other->last_move_point;
+    path->has_current_point = other->has_current_point;
     path->has_curve_to = other->has_curve_to;
-    path->is_box = other->is_box;
-    path->is_region = other->is_region;
+    path->is_rectilinear = other->is_rectilinear;
+    path->maybe_fill_region = other->maybe_fill_region;
+    path->is_empty_fill = other->is_empty_fill;
 
     path->buf.base.num_ops = other->buf.base.num_ops;
     path->buf.base.num_points = other->buf.base.num_points;
@@ -214,9 +221,10 @@ _cairo_path_fixed_equal (const cairo_path_fixed_t *a,
 	return TRUE;
 
     /* use the flags to quickly differentiate based on contents */
-    if (a->has_curve_to != b->has_curve_to ||
-	a->is_region != b->is_region ||
-	a->is_box != b->is_box)
+    if (a->is_empty_fill != b->is_empty_fill ||
+	a->has_curve_to != b->has_curve_to ||
+	a->maybe_fill_region != b->maybe_fill_region ||
+	a->is_rectilinear != b->is_rectilinear)
     {
 	return FALSE;
     }
@@ -378,15 +386,16 @@ _cairo_path_fixed_move_to (cairo_path_fixed_t  *path,
 	if (unlikely (status))
 	    return status;
 
-	if (path->has_current_point && path->is_box) {
+	if (path->has_current_point && path->is_rectilinear) {
 	    /* a move-to is first an implicit close */
-	    path->is_box = path->current_point.x == path->last_move_point.x ||
-		           path->current_point.y == path->last_move_point.y;
-	    path->is_region &= path->is_box;
+	    path->is_rectilinear = path->current_point.x == path->last_move_point.x ||
+		                   path->current_point.y == path->last_move_point.y;
+	    path->maybe_fill_region &= path->is_rectilinear;
 	}
-	if (path->is_region) {
-	    path->is_region = _cairo_fixed_is_integer (x) &&
-		              _cairo_fixed_is_integer (y);
+	if (path->maybe_fill_region) {
+	    path->maybe_fill_region =
+		_cairo_fixed_is_integer (path->last_move_point.x) &&
+		_cairo_fixed_is_integer (path->last_move_point.y);
 	}
     }
 
@@ -437,14 +446,18 @@ _cairo_path_fixed_line_to (cairo_path_fixed_t *path,
 	status = _cairo_path_fixed_move_to (path, point.x, point.y);
     } else {
 	status = _cairo_path_fixed_add (path, CAIRO_PATH_OP_LINE_TO, &point, 1);
-	if (path->is_box) {
-	    path->is_box = path->current_point.x == x ||
-		           path->current_point.y == y;
-	    path->is_region &= path->is_box;
+	if (path->is_rectilinear) {
+	    path->is_rectilinear = path->current_point.x == x ||
+		                   path->current_point.y == y;
+	    path->maybe_fill_region &= path->is_rectilinear;
+	}
+	if (path->maybe_fill_region) {
+	    path->maybe_fill_region = _cairo_fixed_is_integer (x) &&
+		                      _cairo_fixed_is_integer (y);
 	}
-	if (path->is_region) {
-	    path->is_region = _cairo_fixed_is_integer (x) &&
-		              _cairo_fixed_is_integer (y);
+	if (path->is_empty_fill) {
+	    path->is_empty_fill = path->current_point.x == x &&
+		                  path->current_point.y == y;
 	}
     }
 
@@ -495,9 +508,10 @@ _cairo_path_fixed_curve_to (cairo_path_fixed_t	*path,
 
     path->current_point = point[2];
     path->has_current_point = TRUE;
+    path->is_empty_fill = FALSE;
     path->has_curve_to = TRUE;
-    path->is_box = FALSE;
-    path->is_region = FALSE;
+    path->is_rectilinear = FALSE;
+    path->maybe_fill_region = FALSE;
 
     return CAIRO_STATUS_SUCCESS;
 }
@@ -732,49 +746,77 @@ _cairo_path_fixed_interpret (const cairo_path_fixed_t		*path,
     return CAIRO_STATUS_SUCCESS;
 }
 
+typedef struct _cairo_path_fixed_append_closure {
+    cairo_point_t	    offset;
+    cairo_path_fixed_t	    *path;
+} cairo_path_fixed_append_closure_t;
+
 static cairo_status_t
-_append_move_to (void		 *closure,
+_append_move_to (void		 *abstract_closure,
 		 const cairo_point_t  *point)
 {
-    return _cairo_path_fixed_move_to (closure, point->x, point->y);
+    cairo_path_fixed_append_closure_t	*closure = abstract_closure;
+
+    return _cairo_path_fixed_move_to (closure->path,
+				      point->x + closure->offset.x,
+				      point->y + closure->offset.y);
 }
 
 static cairo_status_t
-_append_line_to (void		 *closure,
+_append_line_to (void		 *abstract_closure,
 		 const cairo_point_t *point)
 {
-    return _cairo_path_fixed_line_to (closure, point->x, point->y);
+    cairo_path_fixed_append_closure_t	*closure = abstract_closure;
+
+    return _cairo_path_fixed_line_to (closure->path,
+				      point->x + closure->offset.x,
+				      point->y + closure->offset.y);
 }
 
 static cairo_status_t
-_append_curve_to (void	  *closure,
+_append_curve_to (void	  *abstract_closure,
 		  const cairo_point_t *p0,
 		  const cairo_point_t *p1,
 		  const cairo_point_t *p2)
 {
-    return _cairo_path_fixed_curve_to (closure,
-				       p0->x, p0->y,
-				       p1->x, p1->y,
-				       p2->x, p2->y);
+    cairo_path_fixed_append_closure_t	*closure = abstract_closure;
+
+    return _cairo_path_fixed_curve_to (closure->path,
+				       p0->x + closure->offset.x,
+				       p0->y + closure->offset.y,
+				       p1->x + closure->offset.x,
+				       p1->y + closure->offset.y,
+				       p2->x + closure->offset.x,
+				       p2->y + closure->offset.y);
 }
 
 static cairo_status_t
-_append_close_path (void *closure)
+_append_close_path (void *abstract_closure)
 {
-    return _cairo_path_fixed_close_path (closure);
+    cairo_path_fixed_append_closure_t	*closure = abstract_closure;
+
+    return _cairo_path_fixed_close_path (closure->path);
 }
 
 cairo_status_t
-_cairo_path_fixed_append (cairo_path_fixed_t		  *path,
-			  const cairo_path_fixed_t	  *other,
-			  cairo_direction_t		   dir)
+_cairo_path_fixed_append (cairo_path_fixed_t		    *path,
+			  const cairo_path_fixed_t	    *other,
+			  cairo_direction_t		     dir,
+			  cairo_fixed_t			     tx,
+			  cairo_fixed_t			     ty)
 {
+    cairo_path_fixed_append_closure_t closure;
+
+    closure.path = path;
+    closure.offset.x = tx;
+    closure.offset.y = ty;
+
     return _cairo_path_fixed_interpret (other, dir,
 					_append_move_to,
 					_append_line_to,
 					_append_curve_to,
 					_append_close_path,
-					path);
+					&closure);
 }
 
 static void
@@ -787,6 +829,13 @@ _cairo_path_fixed_offset_and_scale (cairo_path_fixed_t *path,
     cairo_path_buf_t *buf;
     unsigned int i;
 
+    if (path->maybe_fill_region) {
+	path->maybe_fill_region = _cairo_fixed_is_integer (offx) &&
+	                          _cairo_fixed_is_integer (offy) &&
+			          _cairo_fixed_is_integer (scalex) &&
+			          _cairo_fixed_is_integer (scaley);
+    }
+
     cairo_path_foreach_buf_start (buf, path) {
 	 for (i = 0; i < buf->num_points; i++) {
 	     if (scalex != CAIRO_FIXED_ONE)
@@ -800,6 +849,36 @@ _cairo_path_fixed_offset_and_scale (cairo_path_fixed_t *path,
     } cairo_path_foreach_buf_end (buf, path);
 }
 
+void
+_cairo_path_fixed_translate (cairo_path_fixed_t *path,
+			     cairo_fixed_t offx,
+			     cairo_fixed_t offy)
+{
+    cairo_path_buf_t *buf;
+    unsigned int i;
+
+    if (offx == 0 && offy == 0)
+	return;
+
+    if (path->maybe_fill_region &&
+	! (_cairo_fixed_is_integer (offx) && _cairo_fixed_is_integer (offy)))
+    {
+	path->maybe_fill_region = FALSE;
+    }
+
+    path->last_move_point.x += offx;
+    path->last_move_point.y += offx;
+    path->current_point.x += offx;
+    path->current_point.y += offx;
+
+    cairo_path_foreach_buf_start (buf, path) {
+	 for (i = 0; i < buf->num_points; i++) {
+	     buf->points[i].x += offx;
+	     buf->points[i].y += offy;
+	 }
+    } cairo_path_foreach_buf_end (buf, path);
+}
+
 /**
  * _cairo_path_fixed_transform:
  * @path: a #cairo_path_fixed_t to be transformed
@@ -811,12 +890,14 @@ _cairo_path_fixed_offset_and_scale (cairo_path_fixed_t *path,
  **/
 void
 _cairo_path_fixed_transform (cairo_path_fixed_t	*path,
-			     cairo_matrix_t     *matrix)
+			     const cairo_matrix_t     *matrix)
 {
     cairo_path_buf_t *buf;
     unsigned int i;
     double dx, dy;
 
+    /* XXX current_point, last_move_to */
+
     if (matrix->yx == 0.0 && matrix->xy == 0.0) {
 	/* Fast path for the common case of scale+transform */
 	_cairo_path_fixed_offset_and_scale (path,
@@ -827,6 +908,7 @@ _cairo_path_fixed_transform (cairo_path_fixed_t	*path,
 	return;
     }
 
+    path->maybe_fill_region = FALSE;
     cairo_path_foreach_buf_start (buf, path) {
 	 for (i = 0; i < buf->num_points; i++) {
 	    dx = _cairo_fixed_to_double (buf->points[i].x);
@@ -841,20 +923,22 @@ _cairo_path_fixed_transform (cairo_path_fixed_t	*path,
 }
 
 cairo_bool_t
-_cairo_path_fixed_is_equal (cairo_path_fixed_t *path,
-			    cairo_path_fixed_t *other)
+_cairo_path_fixed_is_equal (const cairo_path_fixed_t *path,
+			    const cairo_path_fixed_t *other)
 {
-    cairo_path_buf_t *path_buf, *other_buf;
+    const cairo_path_buf_t *path_buf, *other_buf;
 
     if (path->current_point.x != other->current_point.x ||
 	path->current_point.y != other->current_point.y ||
 	path->has_current_point != other->has_current_point ||
 	path->has_curve_to != other->has_curve_to ||
-	path->is_box != other->is_box ||
-	path->is_region != other->is_region ||
+	path->is_rectilinear != other->is_rectilinear ||
+	path->maybe_fill_region != other->maybe_fill_region ||
 	path->last_move_point.x != other->last_move_point.x ||
 	path->last_move_point.y != other->last_move_point.y)
+    {
 	return FALSE;
+    }
 
     other_buf = cairo_path_head (other);
     cairo_path_foreach_buf_start (path_buf, path) {
@@ -970,25 +1054,16 @@ _cairo_path_fixed_interpret_flat (const cairo_path_fixed_t		*path,
 					&flattener);
 }
 
-cairo_bool_t
-_cairo_path_fixed_is_empty (cairo_path_fixed_t *path)
-{
-    if (cairo_path_head (path)->num_ops == 0)
-	return TRUE;
-
-    return FALSE;
-}
-
 /*
  * Check whether the given path contains a single rectangle.
  */
 cairo_bool_t
-_cairo_path_fixed_is_box (cairo_path_fixed_t *path,
+_cairo_path_fixed_is_box (const cairo_path_fixed_t *path,
 			  cairo_box_t *box)
 {
-    cairo_path_buf_t *buf = cairo_path_head (path);
+    const cairo_path_buf_t *buf = cairo_path_head (path);
 
-    if (! path->is_box)
+    if (! path->is_rectilinear)
 	return FALSE;
 
     /* Do we have the right number of ops? */
@@ -1058,12 +1133,12 @@ _cairo_path_fixed_is_box (cairo_path_fixed_t *path,
  * </programlisting></informalexample>
  */
 cairo_bool_t
-_cairo_path_fixed_is_rectangle (cairo_path_fixed_t *path,
+_cairo_path_fixed_is_rectangle (const cairo_path_fixed_t *path,
 				cairo_box_t        *box)
 {
-    cairo_path_buf_t *buf;
+    const cairo_path_buf_t *buf;
 
-    if (!_cairo_path_fixed_is_box (path, box))
+    if (! _cairo_path_fixed_is_box (path, box))
 	return FALSE;
 
     buf = cairo_path_head (path);
@@ -1075,7 +1150,7 @@ _cairo_path_fixed_is_rectangle (cairo_path_fixed_t *path,
 
 void
 _cairo_path_fixed_iter_init (cairo_path_fixed_iter_t *iter,
-			     cairo_path_fixed_t *path)
+			     const cairo_path_fixed_t *path)
 {
     iter->buf = cairo_path_head (path);
     iter->n_op = 0;