awesome/color.c

/*
 * color.c - color functions
 *
 * Copyright © 2008-2009 Julien Danjou <julien@danjou.info>
 * Copyright © 2009 Uli Schlachter <psychon@znc.in>
 *
 * 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include "color.h"
#include "globalconf.h"

#include <ctype.h>

/* 0xFFFF / 0xFF == 0x101 (257) */
#define RGB_8TO16(i) (((i) & 0xff)   * 0x101)
#define RGB_16TO8(i) (((i) & 0xffff) / 0x101)

/** Parse an hexadecimal color string to its component.
 * \param colstr The color string.
 * \param len The color string length.
 * \param red A pointer to the red color to fill.
 * \param green A pointer to the green color to fill.
 * \param blue A pointer to the blue color to fill.
 * \return True if everything alright.
 */
static bool
color_parse(const char *colstr, ssize_t len,
            uint8_t *red, uint8_t *green, uint8_t *blue)
{
    unsigned long colnum;
    char *p;

    colnum = strtoul(colstr + 1, &p, 16);
    if(len == 9 && (p - colstr) == 9)
    {
        /* We ignore the alpha component */
        colnum >>= 8;
        len -= 2;
        p -= 2;
    }
    if(len != 7 || colstr[0] != '#' || (p - colstr) != 7)
    {
        warn("awesome: error, invalid color '%s'", colstr);
        return false;
    }

    *red   = (colnum >> 16) & 0xff;
    *green = (colnum >> 8) & 0xff;
    *blue  = colnum & 0xff;

    return true;
}

/** Send a request to initialize a X color.
 * If you are only interested in the rgba values and don't need the color's
 * pixel value, you should use color_init_unchecked() instead.
 * \param color color_t struct to store color into.
 * \param colstr Color specification.
 * \param len The length of colstr (which still MUST be NULL terminated).
 * \return request informations.
 */
color_init_request_t
color_init_unchecked(color_t *color, const char *colstr, ssize_t len)
{
    color_init_request_t req;
    uint8_t red, green, blue;

    p_clear(&req, 1);

    if(!len)
    {
        req.has_error = true;
        return req;
    }

    req.color = color;

    /* The color is given in RGB value */
    if(!color_parse(colstr, len, &red, &green, &blue))
    {
        warn("awesome: error, invalid color '%s'", colstr);
        req.has_error = true;
        return req;
    }

    req.cookie_hexa = xcb_alloc_color_unchecked(globalconf.connection,
                                                globalconf.default_cmap,
                                                RGB_8TO16(red),
                                                RGB_8TO16(green),
                                                RGB_8TO16(blue));

    req.has_error = false;
    req.colstr = colstr;

    return req;
}

/** Initialize a X color.
 * \param req color_init request.
 * \return True if color allocation was successful.
 */
bool
color_init_reply(color_init_request_t req)
{
    if(req.has_error)
        return false;

    xcb_alloc_color_reply_t *hexa_color;

    if((hexa_color = xcb_alloc_color_reply(globalconf.connection,
                                           req.cookie_hexa, NULL)))
    {
        req.color->pixel = hexa_color->pixel;
        req.color->red   = hexa_color->red;
        req.color->green = hexa_color->green;
        req.color->blue  = hexa_color->blue;
        req.color->initialized = true;
        p_delete(&hexa_color);
        return true;
    }

    warn("awesome: error, cannot allocate color '%s'", req.colstr);
    return false;
}

/** Push a color as a string onto the stack
 * \param L The Lua VM state.
 * \param c The color to push.
 * \return The number of elements pushed on stack.
 */
int
luaA_pushcolor(lua_State *L, const color_t c)
{
    uint8_t r = RGB_16TO8(c.red);
    uint8_t g = RGB_16TO8(c.green);
    uint8_t b = RGB_16TO8(c.blue);

    char s[10];
    int len = snprintf(s, sizeof(s), "#%02x%02x%02x", r, g, b);
    lua_pushlstring(L, s, len);
    return 1;
}

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