gri3-wm/src/xcb.c

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C
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#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <xcb/xcb.h>
/* All the helper functions needed for efficiently using XCB */
/*
* 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) {
#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 colormapId = xcb_generate_id(conn);
xcb_create_colormap(conn, XCB_COLORMAP_ALLOC_NONE, colormapId, window, root_screen->root_visual);
xcb_alloc_color_reply_t *reply = xcb_alloc_color_reply(conn,
xcb_alloc_color(conn, colormapId, rgb16[0], rgb16[1], rgb16[2]), NULL);
if (!reply) {
printf("color fail\n");
exit(1);
}
uint32_t pixel = reply->pixel;
free(reply);
xcb_free_colormap(conn, colormapId);
return pixel;
}