script: Don't draw backgrounds if they're obscured

When drawing sprites it's a waste to draw the background if the target
area will be obscured by the sprit to draw. Optimize for the common case
where only one sprite is being drawn by peeking at the first item in the
sprite list to check if it is opaque and fills the area.

https://bugs.freedesktop.org/show_bug.cgi?id=87105

diff --git a/src/plugins/splash/script/script-lib-sprite.c b/src/plugins/splash/script/script-lib-sprite.c
index f292d906456f2a79a41f6d31fd080b2077172c22..c49297d0db84bbd52ef7f377097f7ac28337d2eb 100644 (file)
--- a/src/plugins/splash/script/script-lib-sprite.c
+++ b/src/plugins/splash/script/script-lib-sprite.c
@@ -416,6 +416,22 @@ static script_return_t sprite_window_set_background_bottom_color (script_state_t
         return script_return_obj_null ();
 }
 
+static void script_lib_draw_brackground (ply_pixel_buffer_t *pixel_buffer,
+                                         ply_rectangle_t *clip_area,
+                                         script_lib_sprite_data_t *data)
+{
+        if (data->background_color_start == data->background_color_end) {
+                ply_pixel_buffer_fill_with_hex_color (pixel_buffer,
+                                                      clip_area,
+                                                      data->background_color_start);
+        } else {
+                ply_pixel_buffer_fill_with_gradient (pixel_buffer,
+                                                     clip_area,
+                                                     data->background_color_start,
+                                                     data->background_color_end);
+        }
+}
+
 static void script_lib_sprite_draw_area (script_lib_display_t *display,
                                          ply_pixel_buffer_t   *pixel_buffer,
                                          int                   x,
@@ -425,6 +441,7 @@ static void script_lib_sprite_draw_area (script_lib_display_t *display,
 {
         ply_rectangle_t clip_area;
         ply_list_node_t *node;
+        sprite_t *sprite;
         script_lib_sprite_data_t *data = display->data;
 
         clip_area.x = x;
@@ -432,22 +449,33 @@ static void script_lib_sprite_draw_area (script_lib_display_t *display,
         clip_area.width = width;
         clip_area.height = height;
 
-        if (data->background_color_start == data->background_color_end) {
-                ply_pixel_buffer_fill_with_hex_color (pixel_buffer,
-                                                      &clip_area,
-                                                      data->background_color_start);
+
+        node = ply_list_get_first_node (data->sprite_list);
+        sprite = ply_list_node_get_data (node);
+
+        /* Check If the first sprite should be rendered opaque */
+        if (sprite->image && !sprite->remove_me &&
+            ply_pixel_buffer_is_opaque (sprite->image) && sprite->opacity == 1.0)  {
+                int position_x = sprite->x - display->x;
+                int position_y = sprite->y - display->y;
+
+                /* In that case only draw the background if the sprite doesn't
+                 * cover the complete area */
+                if (position_x > x || position_y > y ||
+                    (ply_pixel_buffer_get_width (sprite->image) + position_x) < (x + width) ||
+                    (ply_pixel_buffer_get_height (sprite->image) + position_y) < (y + height))
+                        script_lib_draw_brackground (pixel_buffer, &clip_area, data);
         } else {
-                ply_pixel_buffer_fill_with_gradient (pixel_buffer,
-                                                     &clip_area,
-                                                     data->background_color_start,
-                                                     data->background_color_end);
+                script_lib_draw_brackground (pixel_buffer, &clip_area, data);
         }
+
         for (node = ply_list_get_first_node (data->sprite_list);
              node;
              node = ply_list_get_next_node (data->sprite_list, node)) {
-                sprite_t *sprite = ply_list_node_get_data (node);
                 int position_x, position_y;
 
+                sprite = ply_list_node_get_data (node);
+
                 if (!sprite->image) continue;
                 if (sprite->remove_me) continue;
                 if (sprite->opacity < 0.011) continue;