tests: add output transform tests

This goes through all output transforms with two different buffer transforms
and verifies the visual output against reference images.

This commit introduces a new test input image 'basic-test-card.png'. It is a
small image with deliberately odd and indivisible dimensions to provoke bad
assumptions about image sizes. It contains red, green and blue areas which are
actually text that makes it very obvious if you have e.g. color channels
swapped. It has a white thick circle to highlight aspect ratio issues, and an
orange cross to show a mixed color. The white border is for contrast and a 1px
wide detail. The whole design makes it clear if the image happens to be rotated
or flipped in any way.

The image has one pixel wide transparent border so that bilinear sampling
filter near the edges of the image would produce the same colors with both
Pixman- and GL-renderers which handle the out-of-image samples fundamentally
differently: Pixman assumes (0, 0, 0, 0) samples outside of the image, while
GL-renderer clamps sample coordinates to the edge essentially repeating the
edge pixels.

It would have been "easy" to create a full matrix of
every output scale & transform x every buffer scale & transform, but that
would have resulted in 2 renderers * 8 output transforms * 3 output scales *
8 buffer transforms * 3 buffer scales = 1152 test cases that would have all
ran strictly serially because our test harness has no parallelism inside one
test program. That would have been slow to run, and need a lot more reference
images too.

Instead, I chose to iterate separately through all output scales & transforms
(this patch) and all buffer scales & transforms (next patch). This limits the
number of test cases in this patch to 56, and allows the two test programs to
run in parallel.

I did not even pick all possible scale & transform combinations here, but just
what I think is a representative sub-set to hopefully exercise all the code
paths.

https://gitlab.freedesktop.org/wayland/weston/issues/52

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

tests/meson.build

@@ -132,6 +132,7 @@ tests = [
 			linux_explicit_synchronization_unstable_v1_protocol_c,
 		],
 	},
+	{	'name': 'output-transforms', },
 	{	'name': 'plugin-registry', },
 	{
 		'name': 'pointer',

tests/output-transforms-test.c

@@ -0,0 +1,137 @@
+/*
+ * Copyright © 2020 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#include "weston-test-client-helper.h"
+#include "weston-test-fixture-compositor.h"
+
+#define TRANSFORM(x) WL_OUTPUT_TRANSFORM_ ## x, #x
+#define RENDERERS(s, t) \
+	{ RENDERER_PIXMAN, s, TRANSFORM(t) }, \
+	{ RENDERER_GL,     s, TRANSFORM(t) }
+
+struct setup_args {
+	enum renderer_type renderer;
+	int scale;
+	enum wl_output_transform transform;
+	const char *transform_name;
+};
+
+static const struct setup_args my_setup_args[] = {
+	RENDERERS(1, NORMAL),
+	RENDERERS(1, 90),
+	RENDERERS(1, 180),
+	RENDERERS(1, 270),
+	RENDERERS(1, FLIPPED),
+	RENDERERS(1, FLIPPED_90),
+	RENDERERS(1, FLIPPED_180),
+	RENDERERS(1, FLIPPED_270),
+	RENDERERS(2, NORMAL),
+	RENDERERS(3, NORMAL),
+	RENDERERS(2, 90),
+	RENDERERS(2, 180),
+	RENDERERS(2, FLIPPED),
+	RENDERERS(3, FLIPPED_270),
+};
+
+static enum test_result_code
+fixture_setup(struct weston_test_harness *harness, const struct setup_args *arg)
+{
+	struct compositor_setup setup;
+
+	/* The width and height are chosen to produce 324x240 framebuffer, to
+	 * emulate keeping the video mode constant.
+	 * This resolution is divisible by 2 and 3.
+	 * Headless multiplies the given size by scale.
+	 */
+
+	compositor_setup_defaults(&setup);
+	setup.renderer = arg->renderer;
+	setup.width = 324 / arg->scale;
+	setup.height = 240 / arg->scale;
+	setup.scale = arg->scale;
+	setup.transform = arg->transform;
+	setup.shell = SHELL_TEST_DESKTOP;
+
+	return weston_test_harness_execute_as_client(harness, &setup);
+}
+DECLARE_FIXTURE_SETUP_WITH_ARG(fixture_setup, my_setup_args);
+
+struct buffer_args {
+	int scale;
+	enum wl_output_transform transform;
+	const char *transform_name;
+};
+
+static const struct buffer_args my_buffer_args[] = {
+	{ 1, TRANSFORM(NORMAL) },
+	{ 2, TRANSFORM(90) },
+};
+
+TEST_P(output_transform, my_buffer_args)
+{
+	const struct buffer_args *bargs = data;
+	const struct setup_args *oargs;
+	struct client *client;
+	bool match;
+	char *refname;
+	int ret;
+
+	oargs = &my_setup_args[get_test_fixture_index()];
+
+	ret = asprintf(&refname, "output_%d-%s_buffer_%d-%s",
+		       oargs->scale, oargs->transform_name,
+		       bargs->scale, bargs->transform_name);
+	assert(ret);
+
+	testlog("%s: %s\n", get_test_name(), refname);
+
+	/*
+	 * NOTE! The transform set below is a lie.
+	 * Take that into account when analyzing screenshots.
+	 */
+
+	client = create_client();
+	client->surface = create_test_surface(client);
+	client->surface->width = 10000; /* used only for damage */
+	client->surface->height = 10000;
+	client->surface->buffer = client_buffer_from_image_file(client,
+							"basic-test-card",
+							bargs->scale);
+	wl_surface_set_buffer_scale(client->surface->wl_surface, bargs->scale);
+	wl_surface_set_buffer_transform(client->surface->wl_surface,
+					bargs->transform);
+	move_client(client, 19, 19);
+
+	match = verify_screen_content(client, refname, 0, NULL, 0);
+	assert(match);
+
+	client_destroy(client);
+}

tests/weston-test-client-helper.c

@@ -1118,6 +1118,16 @@ screenshot_reference_filename(const char *basename, uint32_t seq)
 	return filename;
 }
 
+char *
+image_filename(const char *basename)
+{
+	char *filename;
+
+	if (asprintf(&filename, "%s/%s.png", reference_path(), basename) < 0)
+		assert(0);
+	return filename;
+}
+
 struct format_map_entry {
 	cairo_format_t cairo;
 	pixman_format_code_t pixman;
@@ -1694,3 +1704,55 @@ verify_screen_content(struct client *client,
 
 	return match;
 }
+
+/**
+ * Create a wl_buffer from a PNG file
+ *
+ * Loads the named PNG file from the directory of reference images,
+ * creates a wl_buffer with scale times the image dimensions in pixels,
+ * and copies the image content into the buffer using nearest-neighbor filter.
+ *
+ * \param client The client, for the Wayland connection.
+ * \param basename The PNG file name without .png suffix.
+ * \param scale Upscaling factor >= 1.
+ */
+struct buffer *
+client_buffer_from_image_file(struct client *client,
+			      const char *basename,
+			      int scale)
+{
+	struct buffer *buf;
+	char *fname;
+	pixman_image_t *img;
+	int buf_w, buf_h;
+	pixman_transform_t scaling;
+
+	assert(scale >= 1);
+
+	fname = image_filename(basename);
+	img = load_image_from_png(fname);
+	free(fname);
+	assert(img);
+
+	buf_w = scale * pixman_image_get_width(img);
+	buf_h = scale * pixman_image_get_height(img);
+	buf = create_shm_buffer_a8r8g8b8(client, buf_w, buf_h);
+
+	pixman_transform_init_scale(&scaling,
+				    pixman_fixed_1 / scale,
+				    pixman_fixed_1 / scale);
+	pixman_image_set_transform(img, &scaling);
+	pixman_image_set_filter(img, PIXMAN_FILTER_NEAREST, NULL, 0);
+
+	pixman_image_composite32(PIXMAN_OP_SRC,
+				 img, /* src */
+				 NULL, /* mask */
+				 buf->image, /* dst */
+				 0, 0, /* src x,y */
+				 0, 0, /* mask x,y */
+				 0, 0, /* dst x,y */
+				 buf_w, buf_h);
+	pixman_image_unref(img);
+
+	return buf;
+}

tests/weston-test-client-helper.h

@@ -235,6 +235,9 @@ screenshot_output_filename(const char *basename, uint32_t seq);
 char *
 screenshot_reference_filename(const char *basename, uint32_t seq);
 
+char *
+image_filename(const char *basename);
+
 bool
 check_images_match(pixman_image_t *img_a, pixman_image_t *img_b,
 		   const struct rectangle *clip,
@@ -261,4 +264,9 @@ verify_screen_content(struct client *client,
 		      const struct rectangle *clip,
 		      int seq_no);
 
+struct buffer *
+client_buffer_from_image_file(struct client *client,
+			      const char *basename,
+			      int scale);
+
 #endif