tests: Migrate screenshot code from internal test to client helpers

These routines provide test cases an ability to capture screen images
for rendering verification.

This commit is a no-change refactoring, except for making the routines
non-static.  Makefile rules are also updated; most notably, this links
test clients against the cairo libraries now.

v2: Fix pointer code styling, suggested in review

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>

1 files changed, 158 insertions, 0 deletions

diff --git a/tests/weston-test-client-helper.c b/tests/weston-test-client-helper.c
index 65a8880b..16786d9b 100644
--- a/tests/weston-test-client-helper.c
+++ b/tests/weston-test-client-helper.c
@@ -31,7 +31,9 @@
 #include <unistd.h>
 #include <errno.h>
 #include <sys/mman.h>
+#include <cairo.h>
 
+#include "zalloc.h"
 #include "shared/os-compatibility.h"
 #include "weston-test-client-helper.h"
 
@@ -979,3 +981,159 @@ check_surfaces_match_in_clip(const struct surface *a, const struct surface *b, c
 
 	return true;
 }
+
+/** write_surface_as_png()
+ *
+ * Writes out a given weston test surface to disk as a PNG image
+ * using the provided filename (with path).
+ *
+ * @returns true if successfully saved file; false otherwise.
+ */
+bool
+write_surface_as_png(const struct surface *weston_surface, const char *fname)
+{
+	cairo_surface_t *cairo_surface;
+	cairo_status_t status;
+	int bpp = 4; /* Assume ARGB */
+	int stride = bpp * weston_surface->width;
+
+	cairo_surface = cairo_image_surface_create_for_data(weston_surface->data,
+							    CAIRO_FORMAT_ARGB32,
+							    weston_surface->width,
+							    weston_surface->height,
+							    stride);
+	printf("Writing PNG to disk\n");
+	status = cairo_surface_write_to_png(cairo_surface, fname);
+	if (status != CAIRO_STATUS_SUCCESS) {
+		printf("Failed to save screenshot: %s\n",
+		       cairo_status_to_string(status));
+		return false;
+	}
+	cairo_surface_destroy(cairo_surface);
+	return true;
+}
+
+/** load_surface_from_png()
+ *
+ * Reads a PNG image from disk using the given filename (and path)
+ * and returns as a freshly allocated weston test surface.
+ *
+ * @returns weston test surface with image, which should be free'd
+ * when no longer used; or, NULL in case of error.
+ */
+struct surface *
+load_surface_from_png(const char *fname)
+{
+	struct surface *reference;
+	cairo_surface_t *reference_cairo_surface;
+	cairo_status_t status;
+	size_t source_data_size;
+	int bpp;
+	int stride;
+
+	reference_cairo_surface = cairo_image_surface_create_from_png(fname);
+	status = cairo_surface_status(reference_cairo_surface);
+	if (status != CAIRO_STATUS_SUCCESS) {
+		printf("Could not open %s: %s\n", fname, cairo_status_to_string(status));
+		cairo_surface_destroy(reference_cairo_surface);
+		return NULL;
+	}
+
+	/* Disguise the cairo surface in a weston test surface */
+	reference = zalloc(sizeof *reference);
+	if (reference == NULL) {
+		perror("zalloc reference");
+		cairo_surface_destroy(reference_cairo_surface);
+		return NULL;
+	}
+	reference->width = cairo_image_surface_get_width(reference_cairo_surface);
+	reference->height = cairo_image_surface_get_height(reference_cairo_surface);
+	stride = cairo_image_surface_get_stride(reference_cairo_surface);
+	source_data_size = stride * reference->height;
+
+	/* Check that the file's stride matches our assumption */
+	bpp = 4;
+	if (stride != bpp * reference->width) {
+		printf("Mismatched stride for screenshot reference image %s\n", fname);
+		cairo_surface_destroy(reference_cairo_surface);
+		free(reference);
+		return NULL;
+	}
+
+	/* Allocate new buffer for our weston reference, and copy the data from
+	   the cairo surface so we can destroy it */
+	reference->data = zalloc(source_data_size);
+	if (reference->data == NULL) {
+		perror("zalloc reference data");
+		cairo_surface_destroy(reference_cairo_surface);
+		free(reference);
+		return NULL;
+	}
+	memcpy(reference->data,
+	       cairo_image_surface_get_data(reference_cairo_surface),
+	       source_data_size);
+
+	cairo_surface_destroy(reference_cairo_surface);
+	return reference;
+}
+
+/** 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->wl_buffer = create_shm_buffer(client,
+						  client->output->width,
+						  client->output->height,
+						  &screenshot->data);
+	screenshot->height = client->output->height;
+	screenshot->width = client->output->width;
+
+	return screenshot;
+}
+
+/** capture_screenshot_of_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.
+ *
+ * @returns a new surface object, which should be free'd when no
+ * longer needed.
+ */
+struct surface *
+capture_screenshot_of_output(struct client *client)
+{
+	struct surface *screenshot;
+
+	/* Create a surface to hold the screenshot */
+	screenshot = create_screenshot_surface(client);
+
+	client->test->buffer_copy_done = 0;
+	weston_test_capture_screenshot(client->test->weston_test,
+				       client->output->wl_output,
+				       screenshot->wl_buffer);
+	while (client->test->buffer_copy_done == 0)
+		if (wl_display_dispatch(client->wl_display) < 0)
+			break;
+
+	/* FIXME: Document somewhere the orientation the screenshot is taken
+	 * and how the clip coords are interpreted, in case of scaling/transform.
+	 * If we're using read_pixels() just make sure it is documented somewhere.
+	 * Protocol docs in the XML, comparison function docs in Doxygen style.
+	 */
+
+	return screenshot;
+}