Update display list tile skipping.

When we meet cached tiles when rendering the display list, we need to
skip over their contents. Previously we did this by skipping
display list nodes in their entirety.

With the new display list scheme however, we cannot simply skip
nodes completely as the graphic state changes must be remembered.

We therefore update the list playback routine to keep track of the
clip depth and to skip the function calls as required.

1 files changed, 12 insertions, 28 deletions

diff --git a/source/fitz/list-device.c b/source/fitz/list-device.c
index c4a1b9f4..fc2bb3f8 100644
--- a/source/fitz/list-device.c
+++ b/source/fitz/list-device.c
@@ -1377,33 +1377,6 @@ fz_drop_display_list(fz_context *ctx, fz_display_list *list)
 	fz_drop_storable(ctx, &list->storable);
 }
 
-static fz_display_node *
-skip_to_end_tile(fz_display_node *node, fz_display_node *node_end, int *progress)
-{
-	fz_display_node *next;
-	int depth = 1;
-
-	do
-	{
-		next = node + node->size;
-		if (next == node_end)
-			break;
-		if (next->cmd == FZ_CMD_BEGIN_TILE)
-			depth++;
-		else if (next->cmd == FZ_CMD_END_TILE)
-		{
-			depth--;
-			if (depth == 0)
-				return next;
-		}
-		(*progress)++;
-		node = next;
-	}
-	while (1);
-
-	return NULL;
-}
-
 void
 fz_run_display_list(fz_context *ctx, fz_display_list *list, fz_device *dev, const fz_matrix *top_ctm, const fz_rect *scissor, fz_cookie *cookie)
 {
@@ -1426,6 +1399,7 @@ fz_run_display_list(fz_context *ctx, fz_display_list *list, fz_device *dev, cons
 	/* Transformed versions of graphic state entries */
 	fz_rect trans_rect;
 	fz_matrix trans_ctm;
+	int tile_skip_depth = 0;
 
 	fz_var(colorspace);
 
@@ -1568,6 +1542,16 @@ fz_run_display_list(fz_context *ctx, fz_display_list *list, fz_device *dev, cons
 			node += SIZE_IN_NODES(sizeof(fz_stroke_state *));
 		}
 
+		if (tile_skip_depth > 0)
+		{
+			if (n.cmd == FZ_CMD_BEGIN_TILE)
+				tile_skip_depth++;
+			else if (n.cmd == FZ_CMD_END_TILE)
+				tile_skip_depth--;
+			if (tile_skip_depth > 0)
+				continue;
+		}
+
 		trans_rect = rect;
 		fz_transform_rect(&trans_rect, top_ctm);
 
@@ -1698,7 +1682,7 @@ visible:
 				tile_rect = data->view;
 				cached = fz_begin_tile_id(ctx, dev, &rect, &tile_rect, data->xstep, data->ystep, &trans_ctm, n.flags);
 				if (cached)
-					next_node = skip_to_end_tile(node, node_end, &progress);
+					tile_skip_depth = 1;
 				break;
 			}
 			case FZ_CMD_END_TILE: