i3/src/xcb.c

/*
 * vim:ts=8:expandtab
 *
 * i3 - an improved dynamic tiling window manager
 *
 * © 2009 Michael Stapelberg and contributors
 *
 * See file LICENSE for license information.
 *
 * xcb.c: Helper functions for easier usage of XCB
 *
 */
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include <xcb/xcb.h>

#include "util.h"

/*
 * Returns the colorpixel to use for the given hex color (think of HTML).
 *
 * The hex_color has to start with #, for example #FF00FF.
 *
 * NOTE that get_colorpixel() does _NOT_ check the given color code for validity.
 * This has to be done by the caller.
 *
 */
uint32_t get_colorpixel(xcb_connection_t *conn, xcb_window_t window, char *hex) {
        /* TODO: We need to store the colorpixels per child to remove these unnecessary requests every time */
        #define RGB_8_TO_16(i) (65535 * ((i) & 0xFF) / 255)
        char strgroups[3][3] = {{hex[1], hex[2], '\0'},
                                {hex[3], hex[4], '\0'},
                                {hex[5], hex[6], '\0'}};
        int rgb16[3] = {RGB_8_TO_16(strtol(strgroups[0], NULL, 16)),
                        RGB_8_TO_16(strtol(strgroups[1], NULL, 16)),
                        RGB_8_TO_16(strtol(strgroups[2], NULL, 16))};

        xcb_screen_t *root_screen = xcb_setup_roots_iterator(xcb_get_setup(conn)).data;

        xcb_colormap_t colormap_id = xcb_generate_id(conn);
        xcb_void_cookie_t cookie = xcb_create_colormap_checked(conn, XCB_COLORMAP_ALLOC_NONE,
                                   colormap_id, window, root_screen->root_visual);
        check_error(conn, cookie, "Could not create colormap");
        xcb_alloc_color_reply_t *reply = xcb_alloc_color_reply(conn,
                        xcb_alloc_color(conn, colormap_id, rgb16[0], rgb16[1], rgb16[2]), NULL);

        if (!reply) {
                printf("Could not allocate color\n");
                exit(1);
        }

        uint32_t pixel = reply->pixel;
        free(reply);
        xcb_free_colormap(conn, colormap_id);
        return pixel;
}