Color Management

Conversion of Color Data Types and Management of Colors and Color Pairs. More...

Functions
int	get_clr_pair (int fg, int bg)
	Get color pair index for foreground and background colors.
int	rgb_to_curses_clr (RGB *rgb)
	Get color index for RGB color.
int	rgb_to_xterm256_idx (RGB *rgb)
	Convert RGB color to XTerm 256 color index.
RGB	xterm256_idx_to_rgb (int idx)
	Convert XTerm 256 color index to RGB color.
void	apply_gamma (RGB *rgb)
	Apply gamma correction to RGB color.
bool	init_clr_palette (SIO *sio)
	Initialize color palette based on SIO settings.
void	init_hex_clr (int idx, char *s)
	Initialize extended ncurses color from HTML style hex string.
RGB	hex_clr_str_to_rgb (char *s)
	Convert six-digit HTML style hex color code to RGB struct.
cchar_t	mkccc (int cp)
	Create a cchar_t with the specified color pair index.
int	clr_name_to_idx (char *s)
	Get color index from color name.
void	list_colors ()
	list colors to stderr

Detailed Description

Conversion of Color Data Types and Management of Colors and Color Pairs.

Function Documentation

apply_gamma()

void apply_gamma

(

RGB *

rgb

)

Apply gamma correction to RGB color.

Parameters

rgb	Pointer to RGB color

Note

This function modifies the RGB color in place. It applies gamma correction to the RGB color based on the gamma values set in the SIO struct. If the color is a shade of gray, it applies the gray gamma correction. Otherwise, it applies the individual red, green, and blue gamma corrections.

Definition at line 624 of file dwin.c.

                           {
    if (rgb->r == rgb->g && rgb->r == rgb->b) {
        if (GRAY_GAMMA > 0.0f && GRAY_GAMMA != 1.0f) {
            rgb->r = (int)(pow((rgb->r / 255.0f), 1.0f / GRAY_GAMMA) * 255.0f);
            rgb->g = rgb->r;
            rgb->b = rgb->r;
        }
        return;
    }
    if (rgb->r != 0 && RED_GAMMA > 0.0f && RED_GAMMA != 1.0f)
        rgb->r = (int)(pow((rgb->r / 255.0f), 1.0f / RED_GAMMA) * 255.0f);
    if (rgb->g != 0 && GREEN_GAMMA > 0.0f && GREEN_GAMMA != 1.0f)
        rgb->g = (int)(pow((rgb->g / 255.0f), 1.0f / GREEN_GAMMA) * 255.0f);
    if (rgb->b != 0 && BLUE_GAMMA > 0.0f && BLUE_GAMMA != 1.0f)
        rgb->b = (int)(pow((rgb->b / 255.0f), 1.0f / BLUE_GAMMA) * 255.0f);
}

References RGB::b, BLUE_GAMMA, RGB::g, GRAY_GAMMA, GREEN_GAMMA, RGB::r, and RED_GAMMA.

Referenced by init_hex_clr(), and rgb_to_curses_clr().

Here is the caller graph for this function:

clr_name_to_idx()

int clr_name_to_idx

(

char *

s

)

Get color index from color name.

Parameters

s	Color name

Returns

Color index or -1 if not found

Definition at line 1282 of file dwin.c.

                             {
    int i = 0;
    int n = 16;
 
    str_to_lower(s);
    while (i < n) {
        if (!strcmp(colors_text[i], s))
            break;
        i++;
    }
    if (i >= n)
        return (-1);
    return (i);
}

References colors_text, and str_to_lower().

Here is the call graph for this function:

get_clr_pair()

int get_clr_pair	(	int	fg,
		int	bg )

Get color pair index for foreground and background colors.

Parameters

fg	Foreground color index
bg	Background color index

Returns

Color pair index

Definition at line 510 of file dwin.c.

                                 {
    int rc, i, pfg, pbg;
    for (i = 1; i < clr_pair_cnt; i++) {
        extended_pair_content(i, &pfg, &pbg);
        if (pfg == fg && pbg == bg)
            return i;
    }
    if (i >= COLOR_PAIRS) {
        ssnprintf(em0, MAXLEN - 1, "%s, line: %d", __FILE__, __LINE__ - 1);
        ssnprintf(em1, MAXLEN - 1, "NCurses COLOR_PAIRS (%d) exceeded (%d)",
                  COLOR_PAIRS, i);
        strerror_r(errno, em2, MAXLEN);
        display_error(em0, em1, em2, nullptr);
        return (EXIT_FAILURE);
    }
    if (i < COLOR_PAIRS) {
        rc = init_extended_pair(i, fg, bg);
        if (rc == ERR)
            return ERR;
    }
    if (i < COLOR_PAIRS)
        clr_pair_cnt++;
    return i;
}

References clr_pair_cnt, display_error(), em0, em1, em2, and ssnprintf().

Referenced by open_curses(), and parse_ansi_str().

Here is the call graph for this function:

Here is the caller graph for this function:

hex_clr_str_to_rgb()

RGB hex_clr_str_to_rgb

(

char *

s

)

Convert six-digit HTML style hex color code to RGB struct.

Parameters

s	six-digit HTML style hex color code

Definition at line 725 of file dwin.c.

                                {
    RGB rgb;
    sscanf(s, "#%02x%02x%02x", &rgb.r, &rgb.g, &rgb.b);
    return rgb;
}

References RGB::b, RGB::g, and RGB::r.

Referenced by init_hex_clr().

Here is the caller graph for this function:

init_clr_palette()

bool init_clr_palette

(

SIO *

sio

)

Initialize color palette based on SIO settings.

Parameters

sio	Pointer to SIO struct with color settings

Returns

true if successful, false if error

Note

This function initializes the xterm256 color cube and applies any color overrides specified in the SIO struct. The color strings in the SIO struct are expected to be six-digit HTML style hex color codes (e.g., "#RRGGBB"). If a color override is specified for any of the standard colors, it is applied using the init_hex_clr function. After processing all colors, the clr_cnt variable is set to 16 to indicate that the standard colors have been initialized.

Definition at line 651 of file dwin.c.

                                {
    if (sio->black[0])
        init_hex_clr(CLR_BLACK, sio->black);
    if (sio->red[0])
        init_hex_clr(CLR_RED, sio->red);
    if (sio->green[0])
        init_hex_clr(CLR_GREEN, sio->green);
    if (sio->yellow[0])
        init_hex_clr(CLR_YELLOW, sio->yellow);
    if (sio->blue[0])
        init_hex_clr(CLR_BLUE, sio->blue);
    if (sio->magenta[0])
        init_hex_clr(CLR_MAGENTA, sio->magenta);
    if (sio->cyan[0])
        init_hex_clr(CLR_CYAN, sio->cyan);
    if (sio->white[0])
        init_hex_clr(CLR_WHITE, sio->white);
    if (sio->bblack[0])
        init_hex_clr(CLR_BBLACK, sio->bblack);
    if (sio->bred[0])
        init_hex_clr(CLR_BRED, sio->bred);
    if (sio->bgreen[0])
        init_hex_clr(CLR_BGREEN, sio->bgreen);
    if (sio->byellow[0])
        init_hex_clr(CLR_BYELLOW, sio->byellow);
    if (sio->bblue[0])
        init_hex_clr(CLR_BBLUE, sio->bblue);
    if (sio->bmagenta[0])
        init_hex_clr(CLR_BMAGENTA, sio->bmagenta);
    if (sio->bcyan[0])
        init_hex_clr(CLR_BCYAN, sio->bcyan);
    if (sio->bwhite[0])
        init_hex_clr(CLR_BWHITE, sio->bwhite);
    if (sio->borange[0])
        init_hex_clr(CLR_BORANGE, sio->borange);
    if (sio->fg_clr_x[0])
        init_hex_clr(CLR_FG, sio->fg_clr_x);
    if (sio->bg_clr_x[0])
        init_hex_clr(CLR_BG, sio->bg_clr_x);
    if (sio->bo_clr_x[0])
        init_hex_clr(CLR_BO, sio->bo_clr_x);
    if (sio->ln_clr_x[0])
        init_hex_clr(CLR_LN, sio->ln_clr_x);
    if (sio->ln_bg_clr_x[0])
        init_hex_clr(CLR_LN_BG, sio->ln_bg_clr_x);
    clr_cnt = CLR_NCOLORS;
    return true;
}

References SIO::bblack, SIO::bblue, SIO::bcyan, SIO::bg_clr_x, SIO::bgreen, SIO::black, SIO::blue, SIO::bmagenta, SIO::bo_clr_x, SIO::borange, SIO::bred, SIO::bwhite, SIO::byellow, CLR_BBLACK, CLR_BBLUE, CLR_BCYAN, CLR_BG, CLR_BGREEN, CLR_BLACK, CLR_BLUE, CLR_BMAGENTA, CLR_BO, CLR_BORANGE, CLR_BRED, CLR_BWHITE, CLR_BYELLOW, clr_cnt, CLR_CYAN, CLR_FG, CLR_GREEN, CLR_LN, CLR_LN_BG, CLR_MAGENTA, CLR_NCOLORS, CLR_RED, CLR_WHITE, CLR_YELLOW, SIO::cyan, SIO::fg_clr_x, SIO::green, init_hex_clr(), SIO::ln_bg_clr_x, SIO::ln_clr_x, SIO::magenta, SIO::red, SIO::white, and SIO::yellow.

Referenced by open_curses().

Here is the call graph for this function:

Here is the caller graph for this function:

init_hex_clr()

void init_hex_clr	(	int	idx,
		char *	s )

Initialize extended ncurses color from HTML style hex string.

Parameters

idx	Color index
s	Hex color string

Note

NCurses uses 0-1000 for RGB values, so the RGB values from the hex string are converted to this range before initializing the color. If the color index is less than 16, the RGB values are also stored in the StdColors array for reference.

Definition at line 708 of file dwin.c.

                                    {
    RGB rgb;
    rgb = hex_clr_str_to_rgb(s);
    apply_gamma(&rgb);
    if (idx < 16) {
        StdColors[idx].r = rgb.r;
        StdColors[idx].g = rgb.g;
        StdColors[idx].b = rgb.b;
    }
    rgb.r = (rgb.r * 1000) / 255;
    rgb.g = (rgb.g * 1000) / 255;
    rgb.b = (rgb.b * 1000) / 255;
    init_extended_color(idx, rgb.r, rgb.g, rgb.b);
}

References apply_gamma(), RGB::b, RGB::g, hex_clr_str_to_rgb(), RGB::r, and StdColors.

Referenced by init_clr_palette().

Here is the call graph for this function:

Here is the caller graph for this function:

list_colors()

void list_colors

(

)

list colors to stderr

Note

only lists the first 16, since that's how many we let the user redefine

Definition at line 1300 of file dwin.c.

                   {
    int i, col;
 
    for (i = 0, col = 0; i < 16; i++, col++) {
        if (i < 8) {
            fprintf(stderr, " ");
        }
        if (i == 8) {
            col = 0;
            fprintf(stderr, "\n");
        } else if (col > 0)
            fprintf(stderr, " ");
        fprintf(stderr, "%s", colors_text[i]);
    }
    fprintf(stderr, "\n");
}

References colors_text.

mkccc()

cchar_t mkccc

(

int

cp

)

Create a cchar_t with the specified color pair index.

Parameters

cp	Color pair index

Returns

cchar_t with the specified color pair index and a space character as the wide character

Definition at line 766 of file dwin.c.

                      {
    cchar_t cc = {0};
    wchar_t wc = L' ';
    setcchar(&cc, &wc, WA_NORMAL, cp, nullptr);
    return cc;
}

Referenced by open_curses().

Here is the caller graph for this function:

rgb_to_curses_clr()

int rgb_to_curses_clr

(

RGB *

rgb

)

Get color index for RGB color.

Parameters

rgb

RGB color

Returns

NCurses color index

Note

Curses uses 0-1000 for RGB values

If the color does not exist, it is created along with a new color index

Definition at line 541 of file dwin.c.

                                {
    int i;
    int r, g, b;
    apply_gamma(rgb);
    rgb->r = (rgb->r * 1000) / 255;
    rgb->g = (rgb->g * 1000) / 255;
    rgb->b = (rgb->b * 1000) / 255;
    for (i = 0; i < clr_cnt; i++) {
        extended_color_content(i, &r, &g, &b);
        if (rgb->r == r && rgb->g == g && rgb->b == b) {
            return i;
        }
    }
    if (i < COLORS) {
        init_extended_color(i, rgb->r, rgb->g, rgb->b);
        clr_cnt++;
        return clr_cnt - 1;
    }
    return ERR;
}

References apply_gamma(), RGB::b, clr_cnt, RGB::g, and RGB::r.

Referenced by parse_ansi_str().

Here is the call graph for this function:

Here is the caller graph for this function:

rgb_to_xterm256_idx()

int rgb_to_xterm256_idx

(

RGB *

rgb

)

Convert RGB color to XTerm 256 color index.

Parameters

rgb

RGB color

Returns

XTerm 256 color index note This function converts an RGB color to the nearest XTerm 256 color index. It first checks if the color is a shade of gray, and if so, it uses the gray ramp. Otherwise, it calculates the nearest color in the 6x6x6 color cube.

Definition at line 569 of file dwin.c.

                                  {
    if (rgb->r == rgb->g && rgb->g == rgb->b) {
        if (rgb->r < 8)
            return 16;
        if (rgb->r > 248)
            return 231;
        return ((rgb->r - 8) / 10) + 231;
    } else {
        int r_index = (rgb->r < 45) ? 0 : (rgb->r - 60) / 40 + 1;
        int g_index = (rgb->g < 45) ? 0 : (rgb->g - 60) / 40 + 1;
        int b_index = (rgb->b < 45) ? 0 : (rgb->b - 60) / 40 + 1;
        return 16 + (36 * r_index) + (6 * g_index) + b_index;
    }
}

References RGB::b, RGB::g, and RGB::r.

xterm256_idx_to_rgb()

RGB xterm256_idx_to_rgb

(

int

idx

)

Convert XTerm 256 color index to RGB color.

Parameters

idx	XTerm 256 color index

Returns

RGB color note This function converts an XTerm 256 color index to an RGB color. It first checks if the index is in the standard 16 colors, then checks if it's in the 6x6x6 color cube, and finally checks if it's in the gray ramp.

Convert XTerm 256 color index to RGB

Parameters

idx	- XTerm 256 color index

Returns

RGB struct

Definition at line 590 of file dwin.c.

                                 {
    RGB rgb;
    if (idx > 255)
        idx = 255;
    if (idx < 0)
        idx = 0;
    rgb.r = rgb.g = rgb.b = 0;
    if (idx < 16) {
        rgb.r = StdColors[idx].r;
        rgb.g = StdColors[idx].g;
        rgb.b = StdColors[idx].b;
    } else if (idx >= 16 && idx <= 231) {
        idx -= 16;
        rgb.r = (idx / 36) % 6 * 51;
        rgb.g = (idx / 6) % 6 * 51;
        rgb.b = (idx % 6) * 51;
    } else if (idx >= 232 && idx <= 255) {
        int gray = (idx - 232) * 11;
        rgb.r = rgb.g = rgb.b = gray;
    }
    return rgb;
}

References RGB::b, RGB::g, RGB::r, and StdColors.

Referenced by parse_ansi_str().

Here is the caller graph for this function: