Commodore Plus 4 - Page 198

4 Programming Graphics
The graphics statements built into BASIC on the Plus/4 make graphics treatment
in BASIC almost entirely different from that of machine language. No detailed
knowledge of the graphics chip itself is required to do sophisticated high-
resolution
and multicolor graphics on the Plus/4. But, of course, most machine
language programmers will need to control the chip's functions directly. This
chapter is therefore divided into two sections: the first primarily for the BASIC
programmer and the second primarily for the machine language programmer.
Graphics Programming in BASIC
All the BASIC statements used in this chapter are detailed in Chapter 1. When
you need additional information on the use and parameters of a BASIC state
ment, refer to that chapter.
Color and Lrnninance
Your Commodore Plus/4 is capable of producing 16 different colors. Each of
these colors may be modified into eight shades (the eight shades of black are
indistinguishable). This means that the Plus/4 can produce 121 different colors.
In BASIC there are five sources for the colors on the screen. The color for each of
these sources is chosen with the COLOR statement.
COLOR sourcefoolor,luminance
Depending on which graphic mode the Plus/4 is in, different color sources are
available for text and graphics. The uses of color in each mode are explained in
this chapter. The value for color chooses the color:
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