title: 16-color-text-ext

description:
	The "terminal-emulator" comes from an openboot extension
	(wg ieee-std-1275-1994) with status "voluntary-use
	recommended practice". It defines a 16-color terminal
	interface based on iso-6429-1983 escape sequences.
reference:
	./16colord1_2.pdf to be found at
	http://playground.sun.com/1275/practice

fcodes:
>      foreground-color ( -- color-number )
       "value, that defines the color table number that is to
       be used as the foreground color when writing to the
       display buffer" ((value)) initially 0, i.e. black

>      background-color ( -- color-number )
       "value, that defines the color table number that is to
       be used as the background color when writing to the
       display buffer" ((value)) initially 15, i.e. white

>      inverse? ( -- value ) ((value))
       initially false

>      inverse-screen? ( -- value ) ((value))
       initially false

needs-also:
	the actual drawing can be done with the fcodes
	from the fb8 support package. These have an "fb8-"
	prefix, e.g.  => fb8-draw-character => fb8-draw-logo
	=> fb6-invert-screen => fb8-toggle-cursor

predefined-values:
	the first 16 colors are predefined. They take the
	usual semantics and numbers that everyone knows, so
	there are no names needed anyway. The presented names
	are used only for reference here. The recommendation
	uses the values 0, 1/3, 2/3, 1 to defined approximate
	values. For reference, the usual hexadecimal notation
	with with 00,55,AA,FF is used.

> 0x000000 constant #SHADED-BLACK-RGB    0 constant #SHADED-BLACK
> 0x0000AA constant #SHADED-BLUE-RGB     1 constant #SHADED-BLUE
> 0x00AA00 constant #SHADED-GREEN-RGB    2 constant #SHADED-GREEN
> 0x00AAAA constant #SHADED-CYAN-RGB     3 constant #SHADED-CYAN
> 0xAA0000 constant #SHADED-RED-RGB      4 constant #SHADED-RED
> 0xAA00AA constant #SHADED-MAGENTA-RGB  5 constant #SHADED-MAGENTA
> 0xAA5500 constant #SHADED-BROWN-RGB    6 constant #SHADED-BROWN
> 0xAAAAAA constant #SHADED-WHITE-RGB    7 constant #SHADED-WHITE
> 0x555555 constant #SHADED-GRAY-RBG     8 constant #SHADED-GRAY
> 0x5555FF constant #BRIGHT-BLUE-RGB     9 constant #BRIGHT-BLUE
> 0x55FF55 constant #BRIGHT-GREEN-RBG   10 constant #BRIGHT-GREEN
> 0x55FFFF constant #BRIGHT-CYAN-RGB    11 constant #BRIGHT-CYAN
> 0xFF5555 constant #BRIGHT-RED-RBG     12 constant #BRIGHT-RED
> 0xFF55FF constant #BRIGHT-MAGENTA-RBG 13 constant #BRIGHT-MAGENTA
> 0xFFFF55 constant #BRIGHT-YELLOW-RGB  14 constant #BRIGHT-YELLOW
> 0xFFFFFF constant #BRIGHT-WHITE-RGB   15 constant #BRIGHT-WHITE


additional-note:
	../../from/Guido.Draheim: the actual setting of these
	values is actually undefined here. You could use just
	the => TO word for setting the id-constant (0..15).
	Among possible extra words are:
>	set-foreground
>	set-foreground-color
>	foreground!
>	foreground-color!
>	as-foreground-color
	AFAIC, the "foreground-color!" looks nice but most
	platforms need to actually send an escape-sequence
	to the terminal which is why some packages used the
	"set-foreground-color". The others names are probably
	just nicer to write and read. The same variants may
	exists for the inverse attribute which does not
	particularly need a seperate value, right?

	note that this wordset defines that the foreground
	and background color can be set independently which
	contradicts the usecase in some systems.

	In openboot, a device method would be used to set
	a colorcell to an rgb value. The device is just known
	to have the first 16 color cells preset to the values
	shown above. Redefining #BRIGHT-YELLOW to #SHADED-RED
	could be expressed as
>       0xAA 0x00 0x00 14 color!

--- $Id: index-v.txt,v 1.2 2000/10/27 04:21:28 guidod Exp $