Color Management

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

Functions
void	apply_gamma (RGB *rgb)
	Apply gamma correction to RGB color.
int	clr_name_to_idx (char *s)
	Get color index from color name.
void	display_cmplx_str (WINDOW *win, cchar_t *cmplx_buf, int line, int col)
	Display a complex character string on a window.
int	get_clr_pair (int fg, int bg)
	Get color pair index for foreground and background colors.
RGB	hex_clr_str_to_rgb (char *s)
	Convert six-digit HTML style hex color code to RGB struct.
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.
void	list_colors ()
	list colors to stderr
size_t	mk_cmplx_str (cchar_t *cmplx_buf, char *s, attr_t attr, int cp)
	Convert a multibyte string to an array of cchar_t complex characters.
cchar_t	mkccc (int cp, attr_t attr, char *s)
	Create a cchar_t with the specified color pair index.
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.

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.

apply_gamma

Parameters

rgb	Pointer to RGB color

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 401 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().

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clr_name_to_idx()

int clr_name_to_idx

(

char *

s

)

Get color index from color name.

clr_name_to_idx

Parameters

s	Color name

Returns

Color index or -1 if not found

Definition at line 1536 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().

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display_cmplx_str()

void display_cmplx_str	(	WINDOW *	win,
		cchar_t *	cmplx_buf,
		int	line,
		int	col )

Display a complex character string on a window.

display_cmplx_str

Parameters

win	NCurses window to display the string on
cmplx_buf	Array of cchar_t complex characters to display
line	Line number to display the string on
col	Column number to start displaying the string from

This function clears the line where the string will be displayed, then uses wadd_wchstr to add the complex character string (cmplx_buf) to the window. Finally, it moves the cursor to the specified column position.

Definition at line 678 of file dwin.c.

                                                                           {
    wmove(win, line, 0);
    wclrtoeol(win);
    wmove(win, line, 0);
    wadd_wchstr(win, cmplx_buf);
    wmove(win, line, col);
    return;
}

get_clr_pair()

int get_clr_pair	(	int	fg,
		int	bg )

Get color pair index for foreground and background colors.

get_clr_pair

Parameters

fg	Foreground color index
bg	Background color index

Returns

Color pair index

Definition at line 284 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().

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hex_clr_str_to_rgb()

RGB hex_clr_str_to_rgb

(

char *

s

)

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

hex_clr_str_to_rgb

Parameters

s	six-digit HTML style hex color code

Definition at line 526 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().

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init_clr_palette()

bool init_clr_palette

(

SIO *

sio

)

Initialize color palette based on SIO settings.

init_clr_palette

Parameters

sio	Pointer to SIO struct with color settings

Returns

true if successful, false if error

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 CLR_NCOLORS to indicate that the standard colors have been initialized.

Definition at line 429 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);
 
    if (sio->nt_fg[0])
        init_hex_clr(CLR_NT_FG, sio->nt_fg);
    if (sio->nt_bg[0])
        init_hex_clr(CLR_NT_BG, sio->nt_bg);
 
    if (sio->nt_rev_fg[0])
        init_hex_clr(CLR_NT_REV_FG, sio->nt_rev_fg);
    if (sio->nt_rev_bg[0])
        init_hex_clr(CLR_NT_REV_BG, sio->nt_rev_bg);
 
    if (sio->nt_hl_fg[0])
        init_hex_clr(CLR_NT_HL_FG, sio->nt_hl_fg);
    if (sio->nt_hl_bg[0])
        init_hex_clr(CLR_NT_HL_BG, sio->nt_hl_bg);
 
    if (sio->nt_hl_rev_fg[0])
        init_hex_clr(CLR_NT_HL_REV_FG, sio->nt_hl_rev_fg);
    if (sio->nt_hl_rev_bg[0])
        init_hex_clr(CLR_NT_HL_REV_BG, sio->nt_hl_rev_bg);
 
    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_NT_BG, CLR_NT_FG, CLR_NT_HL_BG, CLR_NT_HL_FG, CLR_NT_HL_REV_BG, CLR_NT_HL_REV_FG, CLR_NT_REV_BG, CLR_NT_REV_FG, 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::nt_bg, SIO::nt_fg, SIO::nt_hl_bg, SIO::nt_hl_fg, SIO::nt_hl_rev_bg, SIO::nt_hl_rev_fg, SIO::nt_rev_bg, SIO::nt_rev_fg, SIO::red, SIO::white, and SIO::yellow.

Referenced by open_curses().

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init_hex_clr()

void init_hex_clr	(	int	idx,
		char *	s )

Initialize extended ncurses color from HTML style hex string.

init_hex_clr

Parameters

idx	Color index
s	Hex color string

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 508 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().

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list_colors()

void list_colors

(

)

list colors to stderr

list_colors

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

Definition at line 1555 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.

mk_cmplx_str()

size_t mk_cmplx_str	(	cchar_t *	cmplx_buf,
		char *	s,
		attr_t	attr,
		int	cp )

Convert a multibyte string to an array of cchar_t complex characters.

mk_cmplx_str

Parameters

cmplx_buf	Output buffer for complex characters (allocated within the function)
s	Input multibyte string
attr	Attributes to apply to the complex characters
cp	Color pair index for the complex characters

Returns

Number of bytes processed from the input string

This function converts a multibyte string to an array of complex characters (cchar_t) that can be used with NCurses functions. It handles multibyte characters and applies the specified color pair to each character.

Note

cmplx_buf is allocated within the function and should be freed by the caller when no longer needed.

Definition at line 648 of file dwin.c.

                                                                      {
    cchar_t cc = {0};
    wchar_t wstr[2] = {L'\0', L'\0'};
    mbstate_t mbstate;
    memset(&mbstate, 0, sizeof(mbstate));
    size_t len = strlen(s);
    cmplx_buf = calloc(len + 1, sizeof(cchar_t));
 
    while (*s != '\0') {
        mbrtowc(wstr, s, MB_CUR_MAX, &mbstate);
        setcchar(&cc, wstr, attr, cp, nullptr);
        *cmplx_buf++ = cc;
        s += mbrlen(s, MB_CUR_MAX, &mbstate);
    }
    wstr[0] = L'\0';
    wstr[1] = L'\0';
    setcchar(&cc, wstr, attr, cp, nullptr);
    *cmplx_buf++ = cc;
    return len;
}

mkccc()

cchar_t mkccc	(	int	cp,
		attr_t	attr,
		char *	s )

Create a cchar_t with the specified color pair index.

mkccc

Parameters

cp	Color pair index
attr	Attributes to apply to the cchar_t
s	Multibyte string to convert to wide character (only the first character is used)

Returns

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

Definition at line 625 of file dwin.c.

                                            {
    cchar_t cc = {0};
    wchar_t wstr[2] = {L'\0', L'\0'};
    mbstate_t mbstate;
    memset(&mbstate, 0, sizeof(mbstate));
    mbrtowc(wstr, s, MB_CUR_MAX, &mbstate);
    setcchar(&cc, wstr, attr, cp, nullptr);
    return cc;
}

Referenced by open_curses().

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rgb_to_curses_clr()

int rgb_to_curses_clr

(

RGB *

rgb

)

Get color index for RGB color.

rgb_to_curses_clr

Parameters

rgb

RGB color

Returns

NCurses color index

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 315 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().

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rgb_to_xterm256_idx()

int rgb_to_xterm256_idx

(

RGB *

rgb

)

Convert RGB color to XTerm 256 color index.

rgb_to_xterm256_idx

Parameters

rgb

RGB color

Returns

XTerm 256 color index

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 344 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.

xterm256_idx_to_rgb

Parameters

idx	XTerm 256 color index

Returns

RGB color

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 366 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().

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