xcb_alloc_color(3)

Usage

#include <xcb/xproto.h>

Request function

xcb_alloc_color_cookie_t xcb_alloc_color(xcb_connection_t *conn, xcb_colormap_t cmap, uint16_t red, uint16_t green, uint16_t blue);

Reply datastructure

typedef struct xcb_alloc_color_reply_t {
    uint8_t  response_type;
    uint8_t  pad0;
    uint16_t sequence;
    uint32_t length;
    uint16_t red;
    uint16_t green;
    uint16_t blue;
    uint8_t  pad1[2];
    uint32_t pixel;
} xcb_alloc_color_reply_t;

Reply function

xcb_alloc_color_reply_t *xcb_alloc_color_reply(xcb_connection_t *conn, xcb_alloc_color_cookie_t cookie, xcb_generic_error_t **e);

Request arguments

`conn`	The XCB connection to X11.
`cmap`	TODO
`red`	The red value of your color.
`green`	The green value of your color.
`blue`	The blue value of your color.

Reply fields

response_type: The type of this reply, in this case XCB_ALLOC_COLOR. This field is also present in the xcb_generic_reply_t and can be used to tell replies apart from each other.

sequence: The sequence number of the last request processed by the X11 server.

length: The length of the reply, in words (a word is 4 bytes).

red: TODO: NOT YET DOCUMENTED.

green: TODO: NOT YET DOCUMENTED.

blue: TODO: NOT YET DOCUMENTED.

pixel: TODO: NOT YET DOCUMENTED.

Overview

Allocates a read-only colormap entry corresponding to the closest RGB value supported by the hardware. If you are using TrueColor, you can take a shortcut and directly calculate the color pixel value to avoid the round trip. But, for example, on 16-bit color setups (VNC), you can easily get the closest supported RGB value to the RGB value you are specifying.

Return value

Returns an xcb_alloc_color_cookie_t. Errors have to be handled when calling the reply function xcb_alloc_color_reply.

If you want to handle errors in the event loop instead, use xcb_alloc_color_unchecked. See xcb-requests(3) for details.

Errors

xcb_colormap_error_t: The specified colormap cmap does not exist.

Releases

6 releases since Debian 9 (Stretch); the text changed 4 times.