od_set_color()

Selects foreground and background text colors

Synopsis

void od_set_color(INT nForeground, INT nBackground);

Return value

N/A

Description

od_set_color() selects the foreground and background used for subsequently displayed text. It combines both arguments into an IBM-PC attribute and passes the result to od_set_attrib(). ANSI, AVATAR, or RIP operation is required for the color change to take effect on the caller's terminal.

The foreground may be any of the following values:

Value	Color
D_BLACK	Black
D_BLUE	Dark blue
D_GREEN	Dark green
D_CYAN	Dark cyan
D_RED	Dark red
D_MAGENTA	Dark magenta
D_BROWN	Brown
D_GREY	Light grey, historically called dark white
L_BLACK	High-intensity black, normally displayed as dark grey
L_BLUE	Bright blue
L_GREEN	Bright green
L_CYAN	Bright cyan
L_RED	Bright red
L_MAGENTA	Bright magenta
L_YELLOW	Yellow
L_WHITE	Bright white

An ordinary background uses one of the eight D_* values. A blinking background uses the corresponding B_* name:

Ordinary	Blinking
D_BLACK	B_BLACK
D_BLUE	B_BLUE
D_GREEN	B_GREEN
D_CYAN	B_CYAN
D_RED	B_RED
D_MAGENTA	B_MAGENTA
D_BROWN	B_BROWN
D_GREY	B_GREY

The B_* values set the traditional IBM-PC blink bit. A modern terminal may display that bit as a bright background or may ignore blinking; OpenDoors cannot control that terminal preference.

For example:

od_set_color(L_WHITE, D_BLACK);

selects bright white on black. The equivalent combined-attribute call is:

od_set_attrib(L_WHITE | (D_BLACK << 4));

Both arguments must be one of the documented color constants. The function does not independently validate them. When graphics are unavailable, od_set_attrib() leaves the current attribute unchanged and records ERR_NOGRAPHICS.

Example

The following helpers retain the unmodified half of a color while changing the other half. They assume they are the only routines used by the application to select colors:

static INT current_foreground = D_GREY;
static INT current_background = D_BLACK;

static void set_foreground(INT foreground)
{
   current_foreground = foreground;
   od_set_color(current_foreground, current_background);
}

static void set_background(INT background)
{
   current_background = background;
   od_set_color(current_foreground, current_background);
}

They may then be called independently:

set_foreground(L_YELLOW);
set_background(D_BLUE);

See also

od_set_attrib(), od_printf(), od_color_config(), Colors