examples: add gamma-control

examples/gamma-control.c

@@ -0,0 +1,190 @@
+#define _POSIX_C_SOURCE 200809L
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <wayland-client-protocol.h>
+#include <wayland-client.h>
+#include "wlr-gamma-control-unstable-v1-client-protocol.h"
+
+struct output {
+	struct wl_output *wl_output;
+	struct zwlr_gamma_control_v1 *gamma_control;
+	uint32_t ramp_size;
+	int table_fd;
+	uint16_t *table;
+	struct wl_list link;
+};
+
+static struct wl_list outputs;
+static struct zwlr_gamma_control_manager_v1 *gamma_control_manager = NULL;
+
+static int create_anonymous_file(off_t size) {
+	char template[] = "/tmp/wlroots-shared-XXXXXX";
+	int fd = mkstemp(template);
+	if (fd < 0) {
+		return -1;
+	}
+
+	int ret;
+	do {
+		errno = 0;
+		ret = ftruncate(fd, size);
+	} while (errno == EINTR);
+	if (ret < 0) {
+		close(fd);
+		return -1;
+	}
+
+	unlink(template);
+	return fd;
+}
+
+static int create_gamma_table(uint32_t ramp_size, uint16_t **table) {
+	size_t table_size = ramp_size * 3 * sizeof(uint16_t);
+	int fd = create_anonymous_file(table_size);
+	if (fd < 0) {
+		fprintf(stderr, "failed to create anonymous file\n");
+		return -1;
+	}
+
+	void *data =
+		mmap(NULL, table_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (data == MAP_FAILED) {
+		fprintf(stderr, "failed to mmap()\n");
+		close(fd);
+		return -1;
+	}
+
+	*table = data;
+	return fd;
+}
+
+static void gamma_control_handle_gamma_size(void *data,
+		struct zwlr_gamma_control_v1 *gamma_control, uint32_t ramp_size) {
+	struct output *output = data;
+	output->ramp_size = ramp_size;
+	output->table_fd = create_gamma_table(ramp_size, &output->table);
+	if (output->table_fd < 0) {
+		exit(EXIT_FAILURE);
+	}
+}
+
+static void gamma_control_handle_failed(void *data,
+		struct zwlr_gamma_control_v1 *gamma_control) {
+	fprintf(stderr, "failed to set gamma table\n");
+	exit(EXIT_FAILURE);
+}
+
+static const struct zwlr_gamma_control_v1_listener gamma_control_listener = {
+	.gamma_size = gamma_control_handle_gamma_size,
+	.failed = gamma_control_handle_failed,
+};
+
+static void registry_handle_global(void *data, struct wl_registry *registry,
+		uint32_t name, const char *interface, uint32_t version) {
+	if (strcmp(interface, wl_output_interface.name) == 0) {
+		struct output *output = calloc(1, sizeof(struct output));
+		output->wl_output = wl_registry_bind(registry, name,
+			&wl_output_interface, 1);
+		wl_list_insert(&outputs, &output->link);
+	} else if (strcmp(interface,
+			zwlr_gamma_control_manager_v1_interface.name) == 0) {
+		gamma_control_manager = wl_registry_bind(registry, name,
+			&zwlr_gamma_control_manager_v1_interface, 1);
+	}
+}
+
+static void registry_handle_global_remove(void *data,
+		struct wl_registry *registry, uint32_t name) {
+	// Who cares?
+}
+
+static const struct wl_registry_listener registry_listener = {
+	.global = registry_handle_global,
+	.global_remove = registry_handle_global_remove,
+};
+
+static void fill_gamma_table(uint16_t *table, uint32_t ramp_size,
+		double contrast, double brightness, double gamma) {
+	uint16_t *r = table;
+	uint16_t *g = table + ramp_size;
+	uint16_t *b = table + 2 * ramp_size;
+	for (uint32_t i = 0; i < ramp_size; ++i) {
+		double val = (double)i / (ramp_size - 1);
+		val = contrast * pow(val, 1.0 / gamma) + brightness;
+		r[i] = g[i] = b[i] = (uint16_t)(UINT16_MAX * val);
+	}
+}
+
+static const char usage[] = "usage: gamma-control [options]\n"
+	"  -h          show this help message\n"
+	"  -c <value>  set contrast (default: 1)\n"
+	"  -b <value>  set brightness (default: 0)\n"
+	"  -g <value>  set gamma (default: 1)\n";
+
+int main(int argc, char *argv[]) {
+	wl_list_init(&outputs);
+
+	double contrast = 1, brightness = 0, gamma = 1;
+	int opt;
+	while ((opt = getopt(argc, argv, "hc:b:g:")) != -1) {
+		switch (opt) {
+		case 'c':
+			contrast = strtod(optarg, NULL);
+			break;
+		case 'b':
+			brightness = strtod(optarg, NULL);
+			break;
+		case 'g':
+			gamma = strtod(optarg, NULL);
+			break;
+		case 'h':
+		default:
+			fprintf(stderr, usage);
+			return opt == 'h' ? EXIT_SUCCESS : EXIT_FAILURE;
+		}
+	}
+
+	struct wl_display *display = wl_display_connect(NULL);
+	if (display == NULL) {
+		fprintf(stderr, "failed to create display\n");
+		return -1;
+	}
+
+	struct wl_registry *registry = wl_display_get_registry(display);
+	wl_registry_add_listener(registry, &registry_listener, NULL);
+	wl_display_dispatch(display);
+	wl_display_roundtrip(display);
+
+	if (gamma_control_manager == NULL) {
+		fprintf(stderr,
+			"compositor doesn't support wlr-gamma-control-unstable-v1\n");
+		return EXIT_FAILURE;
+	}
+
+	struct output *output;
+	wl_list_for_each(output, &outputs, link) {
+		output->gamma_control = zwlr_gamma_control_manager_v1_get_gamma_control(
+			gamma_control_manager, output->wl_output);
+		zwlr_gamma_control_v1_add_listener(output->gamma_control,
+			&gamma_control_listener, output);
+	}
+	wl_display_roundtrip(display);
+
+	wl_list_for_each(output, &outputs, link) {
+		fill_gamma_table(output->table, output->ramp_size,
+			contrast, brightness, gamma);
+		zwlr_gamma_control_v1_set_gamma(output->gamma_control,
+			output->table_fd);
+	}
+
+	while (wl_display_dispatch(display) != -1) {
+		// This space is intentionnally left blank
+	}
+
+	return EXIT_SUCCESS;
+}

examples/meson.build

@@ -50,6 +50,12 @@ executable(
 	dependencies: [wayland_cursor, wayland_client, wlr_protos, wlroots]
 )
 
+executable(
+	'gamma-control',
+	'gamma-control.c',
+	dependencies: [wayland_cursor, wayland_client, wlr_protos, wlroots]
+)
+
 if libavutil.found() and libavcodec.found() and libavformat.found()
 	executable(
 		'dmabuf-capture',

protocol/meson.build

@@ -56,6 +56,7 @@ client_protocols = [
 	'idle.xml',
 	'screenshooter.xml',
 	'wlr-export-dmabuf-unstable-v1.xml',
+	'wlr-gamma-control-unstable-v1.xml',
 	'wlr-input-inhibitor-unstable-v1.xml',
 	'wlr-layer-shell-unstable-v1.xml',
 	'wlr-screencopy-unstable-v1.xml',