Atari 65XE Owner's Manual page 80

Type GR.0, list the program, and change COLOR 2 in line 20 to
COLOR 1. COLOR 1 selects register 0, and orange is the default color
for register 0. To change the color in register 0, use the SETCOLOR
command. Add the following line:
15 SETCOLOR
When you run the program, the orange lines change to a pinkish color.
You have changed the color of the lines by using SETCOLOR to
change the paint in the bucket (the color in the register), not by using
COLOR to choose a different bucket (register). The color luminance of
register 0 also affects the luminance of the text in the text window.
Now add
42 SETCOLOR
The light green at the right side of the box turns gold. Add one more
line:
62 SETCOLOR 2,11,4
Run the program. Not only does the left side of the box change to
green, but the text window also turns green. Therefore, register 2 also
controls the color of the text window.
Now you should be able to use SETCOLOR and COLOR to achieve a
wide variety of colors and hues in your programs.
Graphics Modes 5 and 7
The differences among modes 3, 5, and 7 can be illustrated very
easily. Change line 10 to
10 GRAPHICS 5
Run the program. The rectangle is much smaller because the pixels
are smaller. With the text window, the mode 3 grid has 39 columns
and 20 rows. The mode 5 grid has 80 columns and 40 rows.
Now change line 10 to
10 GRAPHICS 7
When you run the program, an even smaller rectangle appears. The
grid in mode 7 is 160 columns by 80 rows.
0,4,6
1,2,8
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