Commodore Plus 4 - Page 208

196 Programming Graphics
By the way, characters plotted with CHAR in multicolor mode do not appear the
same as in text mode or high resolution because pairs of bits (not single bits) in the
character pattern determine the color.
Colors in Multicolor Graphic Mode The background and border colors of the
screen can be changed as usual with the commands
COLOR 0,color,luminance
and
COLOR 4z,color,luminance
Three other colors are available in multicolor mode. They are all nonbackground
colors. The foreground color is set with
COLOR I,color,luminance
Multicolor 1 is set with
COLOR 2,color,luminance
Multicolor 2 is set with
COLOR 3,color,luminance
With each of the drawing statements, you can specify which color source to use.
Color management in multicolor graphics is somewhat involved. First, the
background and multicolor 2 are global colors. That is, whenever you change
COLOR 0, everything drawn in background color changes color. Similarly,
whenever you change COLOR 3, everything drawn in multicolor 2 changes color.
Second, each 8-pixel-by-8-pixel (or 4 by 8, using multicolor coordinates) charac
ter cell has its own set of colors and luminances for foreground color and
multicolor 1. This means that all the pixels within a character cell drawn in
foreground color are the same color. Also, all the pixels within a character cell
drawn in multicolor 1 are the same color. But the two colors can be different and
background and multicolor 2 can be used at the same time, allowing up to four
colors within a character cell. And each of the 1000 character cells has its own
independent pair of foreground color and multicolor 1.
Whenever you draw, the foreground color and multicolor 1 for the character
cell you are drawing in are updated to their current values. This means that if you
have changed either of these colors since drawing with them in this character cell,
the pixels you drew before will change color even if you are not now drawing with
their color source.