/*
* libcucul Canvas for ultrafast compositing of Unicode letters
* Copyright (c) 2002-2006 Sam Hocevar <sam@zoy.org>
* All Rights Reserved
*
* $Id$
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the Do What The Fuck You Want To
* Public License, Version 2, as published by Sam Hocevar. See
* http://sam.zoy.org/wtfpl/COPYING for more details.
*/
/*
* This file contains functions for converting colour values between
* various colourspaces.
*/
#include "config.h"
#include "common.h"
#if defined(HAVE_ERRNO_H)
# include <errno.h>
#endif
#include "cucul.h"
#include "cucul_internals.h"
/* RGB colours for the ANSI palette. There is no real standard, so we
* use the same values as gnome-terminal. The 7th colour (brown) is a bit
* special. */
static const uint16_t ansitab[16] =
{
0xf000, 0xf00a, 0xf0a0, 0xf0aa, 0xfa00, 0xfa0a, 0xfa50, 0xfaaa,
0xf555, 0xf55f, 0xf5f5, 0xf5ff, 0xff55, 0xff5f, 0xfff5, 0xffff,
};
/** \brief Set the default colour pair.
*
* This function sets the default ANSI colour pair. String functions such as
* caca_printf() and graphical primitive functions such as caca_draw_line()
* will use these colours.
*
* Color values are those defined in cucul.h, such as CUCUL_COLOR_RED
* or CUCUL_COLOR_TRANSPARENT.
*
* If an error occurs, -1 is returned and \b errno is set accordingly:
* - \c EINVAL At least one of the colour values is invalid.
*
* \param cv A handle to the libcucul canvas.
* \param fg The requested foreground colour.
* \param bg The requested background colour.
* \return 0 in case of success, -1 if an error occurred.
*/
int cucul_set_color(cucul_canvas_t *cv, unsigned char fg, unsigned char bg)
{
if(fg > 0x20 || bg > 0x20)
{
#if defined(HAVE_ERRNO_H)
errno = EINVAL;
#endif
return -1;
}
cv->fgcolor = fg;
cv->bgcolor = bg;
return 0;
}
/** \brief Set the default colour pair (truecolor version).
*
* This function sets the default colour pair. String functions such as
* caca_printf() and graphical primitive functions such as caca_draw_line()
* will use these colours.
*
* Colors are 16-bit ARGB values, each component being coded on 4 bits. For
* instance, 0xf088 is solid dark cyan (A=15 R=0 G=8 B=8), and 0x8fff is
* white with 50% alpha (A=8 R=15 G=15 B=15).
*
* If an error occurs, -1 is returned and \b errno is set accordingly:
* - \c EINVAL At least one of the colour values is invalid.
*
* \param cv A handle to the libcucul canvas.
* \param fg The requested foreground colour.
* \param bg The requested background colour.
* \return 0 in case of success, -1 if an error occurred.
*/
int cucul_set_truecolor(cucul_canvas_t *cv, unsigned int fg, unsigned int bg)
{
if(fg > 0xffff || bg > 0xffff)
{
#if defined(HAVE_ERRNO_H)
errno = EINVAL;
#endif
return -1;
}
if(fg < 0x100)
fg += 0x100;
if(bg < 0x100)
bg += 0x100;
cv->fgcolor = fg;
cv->bgcolor = bg;
return 0;
}
/*
* XXX: the following functions are local
*/
static uint8_t nearest_ansi(uint16_t argb16, uint8_t def)
{
unsigned int i, best, dist;
if(argb16 < CUCUL_COLOR_DEFAULT)
return argb16;
if(argb16 == CUCUL_COLOR_DEFAULT || argb16 == CUCUL_COLOR_TRANSPARENT)
return def;
if(argb16 < 0x5fff) /* too transparent, return default colour */
return def;
best = def;
dist = 0xffff;
for(i = 0; i < 16; i++)
{
unsigned int d = 0;
int a, b;
a = (ansitab[i] >> 8) & 0xf;
b = (argb16 >> 8) & 0xf;
d += (a - b) * (a - b);
a = (ansitab[i] >> 4) & 0xf;
b = (argb16 >> 4) & 0xf;
d += (a - b) * (a - b);
a = ansitab[i] & 0xf;
b = argb16 & 0xf;
d += (a - b) * (a - b);
if(d < dist)
{
dist = d;
best = i;
}
}
return best;
}
uint8_t _cucul_argb32_to_ansi8(uint32_t ch)
{
uint16_t fg = ch & 0xffff;
uint16_t bg = ch >> 16;
return nearest_ansi(fg, CUCUL_COLOR_LIGHTGRAY)
| (nearest_ansi(bg, CUCUL_COLOR_BLACK) << 4);
}
uint8_t _cucul_argb32_to_ansi4fg(uint32_t ch)
{
return nearest_ansi(ch & 0xffff, CUCUL_COLOR_LIGHTGRAY);
}
uint8_t _cucul_argb32_to_ansi4bg(uint32_t ch)
{
return nearest_ansi(ch >> 16, CUCUL_COLOR_BLACK);
}
uint16_t _cucul_argb32_to_rgb12fg(uint32_t ch)
{
uint16_t fg = ch & 0xffff;
if(fg < CUCUL_COLOR_DEFAULT)
return ansitab[fg] & 0x0fff;
if(fg == CUCUL_COLOR_DEFAULT)
return ansitab[CUCUL_COLOR_LIGHTGRAY] & 0x0fff;
if(fg == CUCUL_COLOR_TRANSPARENT)
return ansitab[CUCUL_COLOR_LIGHTGRAY] & 0x0fff;
return fg & 0x0fff;
}
uint16_t _cucul_argb32_to_rgb12bg(uint32_t ch)
{
uint16_t bg = ch >> 16;
if(bg < CUCUL_COLOR_DEFAULT)
return ansitab[bg] & 0x0fff;
if(bg == CUCUL_COLOR_DEFAULT)
return ansitab[CUCUL_COLOR_BLACK] & 0x0fff;
if(bg == CUCUL_COLOR_TRANSPARENT)
return ansitab[CUCUL_COLOR_BLACK] & 0x0fff;
return bg & 0x0fff;
}
#define RGB12TO24(i) \
(((uint32_t)((i & 0xf00) >> 8) * 0x110000) \
| ((uint32_t)((i & 0x0f0) >> 4) * 0x001100) \
| ((uint32_t)(i & 0x00f) * 0x000011))
uint32_t _cucul_argb32_to_rgb24fg(uint32_t ch)
{
return RGB12TO24(_cucul_argb32_to_rgb12fg(ch));
}
uint32_t _cucul_argb32_to_rgb24bg(uint32_t ch)
{
return RGB12TO24(_cucul_argb32_to_rgb12bg(ch));
}
void _cucul_argb32_to_argb4(uint32_t ch, uint8_t argb[8])
{
uint16_t fg = ch & 0xffff;
uint16_t bg = ch >> 16;
if(fg < CUCUL_COLOR_DEFAULT)
fg = ansitab[fg];
else if(fg == CUCUL_COLOR_DEFAULT)
fg = ansitab[CUCUL_COLOR_LIGHTGRAY];
else if(fg == CUCUL_COLOR_TRANSPARENT)
fg = 0x0fff;
if(bg < CUCUL_COLOR_DEFAULT)
bg = ansitab[bg];
else if(bg == CUCUL_COLOR_DEFAULT)
bg = ansitab[CUCUL_COLOR_BLACK];
else if(bg == CUCUL_COLOR_TRANSPARENT)
bg = 0x0fff;
argb[0] = bg >> 12;
argb[1] = (bg >> 8) & 0xf;
argb[2] = (bg >> 4) & 0xf;
argb[3] = bg & 0xf;
argb[4] = fg >> 12;
argb[5] = (fg >> 8) & 0xf;
argb[6] = (fg >> 4) & 0xf;
argb[7] = fg & 0xf;
}