od_set_attrib()

Selects a complete IBM-PC text attribute

Synopsis

void od_set_attrib(INT nColor);

Return value

N/A

Description

od_set_attrib() selects the attribute used for subsequently displayed text and for cells cleared by OpenDoors. nColor is normally a value from 0 through 255 containing the traditional IBM-PC text attribute:

bit 7       blink
bits 6..4   background color (0..7)
bit 3       foreground intensity
bits 2..0   foreground color (0..7)

Thus 0x1e selects an intense yellow foreground on a blue background, while 0x9e requests the same colors with blink. The complete foreground, background, and blink names are listed under Colors. od_set_color() constructs the same byte from separate foreground and background arguments.

A value of -1 is a special request to leave the current attribute unchanged. Other values outside the range of an attribute byte are not part of the public contract.

In AVATAR mode OpenDoors sends the set-attribute command when the requested value differs from the value recorded in od_control.od_cur_attrib, or whenever od_control.od_full_color is enabled. In ANSI mode it emits only the reset, intensity, blink, foreground, and background parameters needed to reach the new value. Enabling od_full_color causes a complete ANSI attribute sequence to be sent each time. The virtual and local screen attributes are updated to the same byte.

When neither ANSI nor AVATAR operation is available, no attribute is changed and ERR_NOGRAPHICS is placed in od_control.od_error. Plain-ASCII terminals do not carry per-character color attributes. The function returns no value.

Example

This example displays all 256 attribute values and accepts a decimal selection:

unsigned char choose_color(void)
{
   unsigned int counter;
   char string[4];

   od_set_attrib(0x07);
   od_disp_str("Available colors:\n\r\n\r");

   for(counter = 0; counter <= 255; ++counter)
   {
      od_set_attrib((INT)counter);
      od_printf("%03u", counter);
      if((counter % 16) == 15)
      {
         od_set_attrib(0x07);
         od_disp_str("\n\r");
      }
   }

   od_set_attrib(0x07);
   od_disp_str("Which color do you prefer: ");
   od_input_str(string, 3, '0', '9');
   return (unsigned char)atoi(string);
}

See also

od_set_color(), od_color_config(), od_printf(), Colors