Handle gamma-control-v1 set_gamma events

References: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4046

include/sway/output.h

@@ -57,6 +57,7 @@ struct sway_output {
 	uint32_t refresh_nsec;
 	int max_render_time; // In milliseconds
 	struct wl_event_source *repaint_timer;
+	bool gamma_lut_changed;
 };
 
 struct sway_output_non_desktop {
@@ -187,6 +188,8 @@ enum wlr_direction opposite_direction(enum wlr_direction d);
 
 void handle_output_layout_change(struct wl_listener *listener, void *data);
 
+void handle_gamma_control_set_gamma(struct wl_listener *listener, void *data);
+
 void handle_output_manager_apply(struct wl_listener *listener, void *data);
 
 void handle_output_manager_test(struct wl_listener *listener, void *data);

include/sway/server.h

@@ -91,6 +91,9 @@ struct sway_server {
 	struct wl_listener output_manager_apply;
 	struct wl_listener output_manager_test;
 
+	struct wlr_gamma_control_manager_v1 *gamma_control_manager_v1;
+	struct wl_listener gamma_control_set_gamma;
+
 	struct {
 		bool locked;
 		struct wlr_session_lock_manager_v1 *manager;

sway/desktop/output.c

@@ -9,6 +9,7 @@
 #include <wlr/render/swapchain.h>
 #include <wlr/render/wlr_renderer.h>
 #include <wlr/types/wlr_buffer.h>
+#include <wlr/types/wlr_gamma_control_v1.h>
 #include <wlr/types/wlr_matrix.h>
 #include <wlr/types/wlr_output_layout.h>
 #include <wlr/types/wlr_output.h>
@@ -564,6 +565,7 @@ static int output_repaint_timer_handler(void *data) {
 	wlr_output->frame_pending = false;
 
 	if (!wlr_output->needs_frame &&
+			!output->gamma_lut_changed &&
 			!pixman_region32_not_empty(&output->damage_ring.current)) {
 		return 0;
 	}
@@ -578,6 +580,19 @@ static int output_repaint_timer_handler(void *data) {
 		fullscreen_con = workspace->current.fullscreen;
 	}
 
+	if (output->gamma_lut_changed) {
+		struct wlr_gamma_control_v1 *gamma_control =
+			wlr_gamma_control_manager_v1_get_control(
+			server.gamma_control_manager_v1, wlr_output);
+		if (!wlr_gamma_control_v1_apply(gamma_control, &wlr_output->pending)) {
+			return 0;
+		}
+		if (!wlr_output_test(wlr_output)) {
+			wlr_output_rollback(wlr_output);
+			wlr_gamma_control_v1_send_failed_and_destroy(gamma_control);
+		}
+	}
+
 	pixman_region32_t frame_damage;
 	get_frame_damage(output, &frame_damage);
 	wlr_output_set_damage(wlr_output, &frame_damage);
@@ -1076,6 +1091,16 @@ void handle_output_layout_change(struct wl_listener *listener,
 	update_output_manager_config(server);
 }
 
+void handle_gamma_control_set_gamma(struct wl_listener *listener, void *data) {
+	struct sway_server *server =
+		wl_container_of(listener, server, gamma_control_set_gamma);
+	const struct wlr_gamma_control_manager_v1_set_gamma_event *event = data;
+
+	struct sway_output *output = event->output->data;
+	output->gamma_lut_changed = true;
+	wlr_output_schedule_frame(output->wlr_output);
+}
+
 static void output_manager_apply(struct sway_server *server,
 		struct wlr_output_configuration_v1 *config, bool test_only) {
 	// TODO: perform atomic tests on the whole backend atomically

sway/server.c

@@ -114,7 +114,11 @@ bool server_init(struct sway_server *server) {
 	server->data_device_manager =
 		wlr_data_device_manager_create(server->wl_display);
 
+	server->gamma_control_manager_v1 =
 		wlr_gamma_control_manager_v1_create(server->wl_display);
+	server->gamma_control_set_gamma.notify = handle_gamma_control_set_gamma;
+	wl_signal_add(&server->gamma_control_manager_v1->events.set_gamma,
+		&server->gamma_control_set_gamma);
 
 	server->new_output.notify = handle_new_output;
 	wl_signal_add(&server->backend->events.new_output, &server->new_output);