Color

Keyword	Abbreviation	Token (hex)	Version(s)	Classification
COLOR	CO{Shift+L}	E7	3.5	Command and Statement
COLOR	COL{Shift+O}	E7	7.0	Command and Statement
ERR$	E{Shift+R}	E7	4.7	Function

Syntax
COLOR colorSource , chipColor [ , chipLuminance ]

Parameters	Type	Legal Value(s)	Default Value	Note(s)
colorSource	Integer	0 to 5 (version 3.5) 0 to 6 (version 7.0)		values 2 and 3 not used in high-resolution bitmap mode values 1 to 3 not used in text mode
chipColor	Integer	1 to 16 (see table below)
chipLuminance	Integer	0 to 7 (version 3.5) 0 to 255 (version 7.0)	see table below	not used in version 7.0

Purpose
Graphics state management; primarily set the chipColor to be used when plotting bitmap pixels using a colorSource. Alternatively, set chipColor for screen's background, border or text.

Remarks
Although the TED and VIC chips have over a dozen colors, they are both limited to using only 2 colors within a color cell (similar to an MPEG macro block) for high-resolution bitmaps or only 4 colors per cell for a multi-color bitmap (and then one of them is a global/shared color). The main reason for this is to decrease the amount memory required to store a bitmap; For the VIC, which has only 16 colors, this results in a 4-to-1 or 4-to-2 "compression" (high-res or multi-color mode). For the TED, which has over a hundred colors, this jumps to about 7-to-1 or 7-to-2.

Said another way, each pixel in the bitmap is stored primarily as a single bit (high-resolution mode) or as pair of bits (multi-color mode). Each possible bit(pair) value may be assigned any of the colors the chip has to offer, but with only 1 or 2 bits, not much variety is possible (which is why the concept of color cells is used). With color cells, the bitmap pixels are clustered together into rectangular regions (which actually correspond with the area for each character in text mode) and each cell may have its own chipColor (and for TED chipLuminance) assigned to each of the possible bit (pair) values. Well actually one of the 4 multi-color values is shared over the full screen and can not be set for each color cell.

Anyway, BASIC uses the colorSource to specify which bit value (or bit-pair value) is to be written into the bitmap for each pixel plotted by the bitmap routines. It also looks-up the chipColor assigned to the colorSource that is being plotted and stores that value in the color cell. Now if you define 2 (high-resolution) or 4 (multi-color) chipColors to the 2 (or 4) different colorSources, and you never change those assignments while generating your bitmap image, you have a "static" color map; or you could say all 2 (or 4) chipColors are global... the memory of the color cells isn't even really needed in that case.

For nice looking images, you probably do want to change chipColors that are assigned while generating a bitmap image. You just need to space your color changes apart on the bitmap so that a color change in one cell does not affect nearby pixels. Failure to do this will result in distotion of the bitmap image when you plot a new chipColor assignment in a cell that was using a previous chipColor assignment (for the same colorSource). Arrr! Its really hard to describe with words, but once you see it happen a few times while playing with the bitmap commands, I think you will understand!

The first parameter, the colorSource specifies what graphic element is changed by the COLOR command as a shown here:

*colorSource*	Refers to	Real or Mapping	Note(s)
0	background	Real (text and multi-color) Mapping (high-resolution)
1	foreground*	Mapping
2	multi-color A	Mapping
3	multi-color B	Mapping
4	border	Real
5	text color	Mapping	v7.0 only; the active text editor (40 or 80 column display)
6	background and border	Real	v7.0 only; 80-column display

* The "foreground" is the default colorSource for bitmap commands, although ironically the VIC-II sprites consider such multi-color pixels as background! See BUMP for details.

The chipColor specifies which of the "primary" colors that can be generated by the video chip is assigned to the colorSource. The TED chip has more colors than the VIC-II and these are specified with the optional chipLuminance parameter. If omitted, the chipLuminance defaults to 7; the table below shows the luminance values that correspond to the text mode colors (accessible with {Control + Number} or {C= + Number} key combinations). The table also includes the control code (CHR$ value) that may be used to change text colors with PRINT.

*chipColor*	CHR$ value	TED Name	TED appearance	TED luminance	VDC Name	VDC appearance	VIC-I Name	VIC-I* appearance	VIC-II Name	VIC-II appearance
1	144	black		0	black		black		black
2	5	white		7	white		white		white
3	28	red		3	red		red		red
4	159	cyan		6	cyan		cyan		cyan
5	156	purple		4	purple		purple		purple
6	30	green		3	green		green		green
7	31	blue		4	blue		blue		blue
8	158	yellow		7	yellow		yellow		yellow
9	129	orange		4	dark purple		orange		orange
10	149	brown		2	brown		light orange		brown
11	150	puke		5	light red		pink		light red
12	151	pink		6	dark cyan		light cyan		dark gray
13	152	sea green		5	dark gray		light purple		medium gray
14	153	indigo		6	light green		light green		light green
15	154	grape		2	light blue		light blue		light blue
16	155	lime		5	light gray		light yellow		light gray

*Only the first 8 colors are available for text and border colors on the VIC-I chip used in the VIC-20.

Any floating-point numbers will first be converted to integers (see INT). If any value is out-of-range (see above) an ILLEGAL QUANTITY ERROR is generated. Specifiying a string for any parameter will generate a TYPE MISMATCH ERROR.

Examples:

COLOR 0,1 : REM set background to black (bitmap or 40-column text screen)
COLOR 1,6 : REM set bitmap foreground to green (high-res or multi-color)
COLOR 2,7 : REM set multi-color A to blue
COLOR 3,3 : REM set multi-color B to red
COLOR 4,5 : REM set border to purple (magenta)
COLOR 5,2 : REM set current text color to white (v7.0 only)
COLOR 6,12 : REM set 80-column background to dark cyan (v7.0 only)

Commodore 64

BASIC 2.0 of the C64 doesn't have a COLOR command. However, setting text colors is pretty easy using PRINT CHR$(n) with an n value from the table above. To set the background or border colors, you need to use a machine-specific POKE. You need to POKE a value one less than shown in the table above. For example, purple has BASIC chipColor 5; you want to POKE a value of 4.

VIC-20

BASIC 2.0 of the VIC-20 doesn't have a COLOR command. However, setting text colors is pretty easy using PRINT CHR$(n) with an n value from the table above. To set the background or border colors, you need to use a machine-specific POKE. You need to POKE a value one less than shown in the table above. For example, purple has BASIC chipColor 5; you want to POKE a value of 4. Note: both the background and border colors are specified by the same POKE location, so a rather messy command involving PEEK, AND, and OR is need to change only one.