obs-studio/plugins/linux-capture/xhelpers.c

/*
Copyright (C) 2014 by Leonhard Oelke <leonhard@in-verted.de>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <stdint.h>
#include <sys/shm.h>
#include <xcb/xcb.h>
#include <xcb/xinerama.h>

#include "xhelpers.h"

bool xinerama_is_active(xcb_connection_t *xcb)
{
	if (!xcb || !xcb_get_extension_data(xcb, &xcb_xinerama_id)->present)
		return false;

	bool active = true;
	xcb_xinerama_is_active_cookie_t xnr_c;
	xcb_xinerama_is_active_reply_t  *xnr_r;

	xnr_c = xcb_xinerama_is_active_unchecked(xcb);
	xnr_r = xcb_xinerama_is_active_reply(xcb, xnr_c, NULL);
	if (!xnr_r || xnr_r->state == 0)
		active = false;
	free(xnr_r);

	return active;
}

int xinerama_screen_count(xcb_connection_t *xcb)
{
	if (!xcb)
		return 0;

	int screens = 0;
	xcb_xinerama_query_screens_cookie_t scr_c;
	xcb_xinerama_query_screens_reply_t  *scr_r;

	scr_c = xcb_xinerama_query_screens_unchecked(xcb);
	scr_r = xcb_xinerama_query_screens_reply(xcb, scr_c, NULL);
	if (scr_r)
		screens = scr_r->number;
	free(scr_r);

	return screens;
}

int xinerama_screen_geo(xcb_connection_t *xcb, int_fast32_t screen,
		int_fast32_t *x, int_fast32_t *y,
		int_fast32_t *w, int_fast32_t *h)
{
	if (!xcb)
		goto fail;

	bool success = false;
	xcb_xinerama_query_screens_cookie_t scr_c;
	xcb_xinerama_query_screens_reply_t  *scr_r;
	xcb_xinerama_screen_info_iterator_t iter;

	scr_c = xcb_xinerama_query_screens_unchecked(xcb);
	scr_r = xcb_xinerama_query_screens_reply(xcb, scr_c, NULL);
	if (!scr_r)
		goto fail;

	iter = xcb_xinerama_query_screens_screen_info_iterator(scr_r);
	for (; iter.rem; --screen, xcb_xinerama_screen_info_next(&iter)) {
		if (!screen) {
			*x = iter.data->x_org;
			*y = iter.data->y_org;
			*w = iter.data->width;
			*h = iter.data->height;
			success = true;
		}
	}
	free(scr_r);

	if (success)
		return 0;

fail:
	*x = *y = *w = *h = 0;
	return -1;
}

int x11_screen_geo(xcb_connection_t *xcb, int_fast32_t screen,
		int_fast32_t *w, int_fast32_t *h)
{
	if (!xcb)
		goto fail;

	bool success = false;
	xcb_screen_iterator_t iter;

	iter = xcb_setup_roots_iterator(xcb_get_setup(xcb));
	for (; iter.rem; --screen, xcb_screen_next(&iter)) {
		if (!screen) {
			*w = iter.data->width_in_pixels;
			*h = iter.data->height_in_pixels;
			success = true;
		}
	}

	if (success)
		return 0;

fail:
	*w = *h = 0;
	return -1;
}

xcb_shm_t* xshm_xcb_attach(xcb_connection_t *xcb, const int w, const int h)
{
	if (!xcb)
		return NULL;

	xcb_shm_t *shm = bzalloc(sizeof(xcb_shm_t));
	shm->xcb       = xcb;
	shm->seg       = xcb_generate_id(shm->xcb);

	shm->shmid = shmget(IPC_PRIVATE, w * h * 4, IPC_CREAT | 0777);
	if (shm->shmid == -1)
		goto fail;

	xcb_shm_attach(shm->xcb, shm->seg, shm->shmid, false);

	shm->data = shmat(shm->shmid, NULL, 0);

	return shm;
fail:
	xshm_xcb_detach(shm);
	return NULL;
}

void xshm_xcb_detach(xcb_shm_t *shm)
{
	if (!shm)
		return;

	xcb_shm_detach(shm->xcb, shm->seg);

	if ((char *) shm->data != (char *) -1)
		shmdt(shm->data);

	if (shm->shmid != -1)
		shmctl(shm->shmid, IPC_RMID, NULL);

	bfree(shm);
}

xcb_screen_t *xcb_get_screen(xcb_connection_t *xcb, int screen)
{
	xcb_screen_iterator_t iter;

	iter = xcb_setup_roots_iterator(xcb_get_setup(xcb));
	for (; iter.rem; --screen, xcb_screen_next(&iter)) {
		if (screen == 0)
			return iter.data;
	}

	return NULL;
}