tests: make screenshooting return a buffer

Screenshooting does not involve creating a wl_surface, so using struct
surface is superfluous.

Return a struct buffer instead. It could have been just a
pixman_image_t, but setting up proper destruction would be a bit more
work. Should not hurt to keep the wl_buffer around until the user is
ready to free the image.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniels@collabora.com>

tests/internal-screenshot-test.c

@@ -65,7 +65,7 @@ TEST(internal_screenshot)
 	struct buffer *buf;
 	struct client *client;
 	struct wl_surface *surface;
-	struct surface *screenshot = NULL;
+	struct buffer *screenshot = NULL;
 	pixman_image_t *reference_good = NULL;
 	pixman_image_t *reference_bad = NULL;
 	struct rectangle clip;
@@ -123,8 +123,7 @@ TEST(internal_screenshot)
 	/* Test check_images_match() without a clip.
 	 * We expect this to fail since we use a bad reference image
 	 */
-	match = check_images_match(screenshot->buffer->image,
-				   reference_bad, NULL);
+	match = check_images_match(screenshot->image, reference_bad, NULL);
 	printf("Screenshot %s reference image\n", match? "equal to" : "different from");
 	assert(!match);
 	pixman_image_unref(reference_bad);
@@ -138,18 +137,17 @@ TEST(internal_screenshot)
 	clip.width = 100;
 	clip.height = 100;
 	printf("Clip: %d,%d %d x %d\n", clip.x, clip.y, clip.width, clip.height);
-	match = check_images_match(screenshot->buffer->image,
-				   reference_good, &clip);
+	match = check_images_match(screenshot->image, reference_good, &clip);
 	printf("Screenshot %s reference image in clipped area\n", match? "matches" : "doesn't match");
 	pixman_image_unref(reference_good);
 
 	/* Test dumping of non-matching images */
 	if (!match || dump_all_images) {
 		fname = screenshot_output_filename("internal-screenshot", 0);
-		write_image_as_png(screenshot->buffer->image, fname);
+		write_image_as_png(screenshot->image, fname);
 	}
 
-	free(screenshot);
+	buffer_destroy(screenshot);
 
 	printf("Test complete\n");
 	assert(match);

tests/weston-test-client-helper.c

@@ -1255,54 +1255,29 @@ load_image_from_png(const char *fname)
 	return converted;
 }
 
-/** create_screenshot_surface()
- *
- *  Allocates and initializes a weston test surface for use in
- *  storing a screenshot of the client's output.  Establishes a
- *  shm backed wl_buffer for retrieving screenshot image data
- *  from the server, sized to match the client's output display.
- *
- *  @returns stack allocated surface image, which should be
- *  free'd when done using it.
- */
-struct surface *
-create_screenshot_surface(struct client *client)
-{
-	struct surface *screenshot;
-	screenshot = zalloc(sizeof *screenshot);
-	if (screenshot == NULL)
-		return NULL;
-
-	screenshot->buffer = create_shm_buffer_a8r8g8b8(client,
-							client->output->width,
-							client->output->height);
-	screenshot->height = client->output->height;
-	screenshot->width = client->output->width;
-
-	return screenshot;
-}
-
-/** capture_screenshot_of_output()
+/**
+ * Take screenshot of a single output
  *
  * Requests a screenshot from the server of the output that the
- * client appears on.  The image data returned from the server
- * can be accessed from the screenshot surface's data member.
+ * client appears on. This implies that the compositor goes through an output
+ * repaint to provide the screenshot before this function returns. This
+ * function is therefore both a server roundtrip and a wait for a repaint.
  *
- * @returns a new surface object, which should be free'd when no
- * longer needed.
+ * @returns A new buffer object, that should be freed with buffer_destroy().
  */
-struct surface *
+struct buffer *
 capture_screenshot_of_output(struct client *client)
 {
-	struct surface *screenshot;
+	struct buffer *buffer;
 
-	/* Create a surface to hold the screenshot */
-	screenshot = create_screenshot_surface(client);
+	buffer = create_shm_buffer_a8r8g8b8(client,
+					    client->output->width,
+					    client->output->height);
 
 	client->test->buffer_copy_done = 0;
 	weston_test_capture_screenshot(client->test->weston_test,
 				       client->output->wl_output,
-				       screenshot->buffer->proxy);
+				       buffer->proxy);
 	while (client->test->buffer_copy_done == 0)
 		if (wl_display_dispatch(client->wl_display) < 0)
 			break;
@@ -1313,5 +1288,5 @@ capture_screenshot_of_output(struct client *client)
 	 * Protocol docs in the XML, comparison function docs in Doxygen style.
 	 */
 
-	return screenshot;
+	return buffer;
 }

tests/weston-test-client-helper.h

@@ -207,10 +207,7 @@ write_image_as_png(pixman_image_t *image, const char *fname);
 pixman_image_t *
 load_image_from_png(const char *fname);
 
-struct surface *
-create_screenshot_surface(struct client *client);
-
-struct surface *
+struct buffer *
 capture_screenshot_of_output(struct client *client);
 
 #endif