CGError CGGetDisplayTransferByTable(CGDirectDisplayID display, uint32_t gamma_size, CGGammaValue* red,
CGGammaValue* green, CGGammaValue* blue, uint32_t* gamma_size_out)
{
xcb_randr_get_crtc_gamma_cookie_t gamma_cookie;
xcb_randr_get_crtc_gamma_reply_t* gamma_reply;
xcb_generic_error_t* error;
uint16_t* r_int;
uint16_t* g_int;
uint16_t* b_int;
long i;
if (gamma_size != 256)
{
fprintf(stderr, "Gamma size should be 256, got %u\n", gamma_size);
abort();
}
*gamma_size_out = 256;
gamma_cookie = xcb_randr_get_crtc_gamma(conn, crtcs[display]);
gamma_reply = xcb_randr_get_crtc_gamma_reply(conn, gamma_cookie, &error);
if (error)
{
fprintf(stderr, "Failed to write gamma ramps\n");
return ~kCGErrorSuccess;
}
r_int = xcb_randr_get_crtc_gamma_red(gamma_reply);
g_int = xcb_randr_get_crtc_gamma_green(gamma_reply);
b_int = xcb_randr_get_crtc_gamma_blue(gamma_reply);
for (i = 0; i < 256; i++)
{
red[i] = (CGGammaValue)(r_int[i]) / UINT16_MAX;
green[i] = (CGGammaValue)(g_int[i]) / UINT16_MAX;
blue[i] = (CGGammaValue)(b_int[i]) / UINT16_MAX;
}
free(gamma_reply);
return kCGErrorSuccess;
}
int
randr_start(randr_state_t *state)
{
xcb_generic_error_t *error;
int screen_num = state->screen_num;
if (screen_num < 0) screen_num = state->preferred_screen;
/* Get screen */
const xcb_setup_t *setup = xcb_get_setup(state->conn);
xcb_screen_iterator_t iter = xcb_setup_roots_iterator(setup);
state->screen = NULL;
for (int i = 0; iter.rem > 0; i++) {
if (i == screen_num) {
state->screen = iter.data;
break;
}
xcb_screen_next(&iter);
}
if (state->screen == NULL) {
fprintf(stderr, _("Screen %i could not be found.\n"),
screen_num);
return -1;
}
/* Get list of CRTCs for the screen */
xcb_randr_get_screen_resources_current_cookie_t res_cookie =
xcb_randr_get_screen_resources_current(state->conn,
state->screen->root);
xcb_randr_get_screen_resources_current_reply_t *res_reply =
xcb_randr_get_screen_resources_current_reply(state->conn,
res_cookie,
&error);
if (error) {
fprintf(stderr, _("`%s' returned error %d\n"),
"RANDR Get Screen Resources Current",
error->error_code);
return -1;
}
state->crtc_count = res_reply->num_crtcs;
state->crtcs = calloc(state->crtc_count, sizeof(randr_crtc_state_t));
if (state->crtcs == NULL) {
perror("malloc");
state->crtc_count = 0;
return -1;
}
xcb_randr_crtc_t *crtcs =
xcb_randr_get_screen_resources_current_crtcs(res_reply);
/* Save CRTC identifier in state */
for (int i = 0; i < state->crtc_count; i++) {
state->crtcs[i].crtc = crtcs[i];
}
free(res_reply);
/* Save size and gamma ramps of all CRTCs.
Current gamma ramps are saved so we can restore them
at program exit. */
for (int i = 0; i < state->crtc_count; i++) {
xcb_randr_crtc_t crtc = state->crtcs[i].crtc;
/* Request size of gamma ramps */
xcb_randr_get_crtc_gamma_size_cookie_t gamma_size_cookie =
xcb_randr_get_crtc_gamma_size(state->conn, crtc);
xcb_randr_get_crtc_gamma_size_reply_t *gamma_size_reply =
xcb_randr_get_crtc_gamma_size_reply(state->conn,
gamma_size_cookie,
&error);
if (error) {
fprintf(stderr, _("`%s' returned error %d\n"),
"RANDR Get CRTC Gamma Size",
error->error_code);
return -1;
}
unsigned int ramp_size = gamma_size_reply->size;
state->crtcs[i].ramp_size = ramp_size;
free(gamma_size_reply);
if (ramp_size == 0) {
fprintf(stderr, _("Gamma ramp size too small: %i\n"),
ramp_size);
return -1;
}
/* Request current gamma ramps */
xcb_randr_get_crtc_gamma_cookie_t gamma_get_cookie =
xcb_randr_get_crtc_gamma(state->conn, crtc);
xcb_randr_get_crtc_gamma_reply_t *gamma_get_reply =
xcb_randr_get_crtc_gamma_reply(state->conn,
gamma_get_cookie,
&error);
if (error) {
fprintf(stderr, _("`%s' returned error %d\n"),
"RANDR Get CRTC Gamma", error->error_code);
return -1;
}
uint16_t *gamma_r =
xcb_randr_get_crtc_gamma_red(gamma_get_reply);
uint16_t *gamma_g =
xcb_randr_get_crtc_gamma_green(gamma_get_reply);
uint16_t *gamma_b =
xcb_randr_get_crtc_gamma_blue(gamma_get_reply);
/* Allocate space for saved gamma ramps */
state->crtcs[i].saved_ramps =
malloc(3*ramp_size*sizeof(uint16_t));
if (state->crtcs[i].saved_ramps == NULL) {
perror("malloc");
free(gamma_get_reply);
return -1;
}
/* Copy gamma ramps into CRTC state */
memcpy(&state->crtcs[i].saved_ramps[0*ramp_size], gamma_r,
ramp_size*sizeof(uint16_t));
memcpy(&state->crtcs[i].saved_ramps[1*ramp_size], gamma_g,
ramp_size*sizeof(uint16_t));
memcpy(&state->crtcs[i].saved_ramps[2*ramp_size], gamma_b,
ramp_size*sizeof(uint16_t));
free(gamma_get_reply);
}
return 0;
}
