screen-share: move damage calculation after screen resize

Calculate damage region after resizing the cache image. This
avoids unnecessary calculation of damaged regions on resize,
makes sure that the whole screen is considered damaged on
resize and simplifies error handling.

Signed-off-by: Stefan Agner <stefan@agner.ch>

compositor/screen-share.c

@@ -822,22 +822,6 @@ shared_output_repainted(struct wl_listener *listener, void *data)
 	pixman_box32_t *r;
 	uint32_t *cache_data;
 
-	/* Damage in output coordinates */
-	pixman_region32_init(&damage);
-	pixman_region32_intersect(&damage, &so->output->region,
-				  &so->output->previous_damage);
-	pixman_region32_translate(&damage, -so->output->x, -so->output->y);
-
-	/* Apply damage to all buffers */
-	wl_list_for_each(sb, &so->shm.buffers, link)
-		pixman_region32_union(&sb->damage, &sb->damage, &damage);
-
-	/* Transform to buffer coordinates */
-	weston_transformed_region(so->output->width, so->output->height,
-				  so->output->transform,
-				  so->output->current_scale,
-				  &damage, &damage);
-
 	width = so->output->current_mode->width;
 	height = so->output->current_mode->height;
 	stride = width;
@@ -853,12 +837,27 @@ shared_output_repainted(struct wl_listener *listener, void *data)
 						 width, height, NULL,
 						 stride);
 		if (!so->cache_image)
-			goto err_pixman_init;
+			goto err_shared_output;
 
-		pixman_region32_fini(&damage);
 		pixman_region32_init_rect(&damage, 0, 0, width, height);
+	} else {
+		/* Damage in output coordinates */
+		pixman_region32_init(&damage);
+		pixman_region32_intersect(&damage, &so->output->region,
+					  &so->output->previous_damage);
+		pixman_region32_translate(&damage, -so->output->x, -so->output->y);
 	}
 
+	/* Apply damage to all buffers */
+	wl_list_for_each(sb, &so->shm.buffers, link)
+		pixman_region32_union(&sb->damage, &sb->damage, &damage);
+
+	/* Transform to buffer coordinates */
+	weston_transformed_region(so->output->width, so->output->height,
+				  so->output->transform,
+				  so->output->current_scale,
+				  &damage, &damage);
+
 	if (shared_output_ensure_tmp_data(so, &damage) < 0)
 		goto err_pixman_init;
 
@@ -899,6 +898,7 @@ shared_output_repainted(struct wl_listener *listener, void *data)
 
 err_pixman_init:
 	pixman_region32_fini(&damage);
+err_shared_output:
 	shared_output_destroy(so);
 }