Atari 400

Atari Graphics & Sound 281
With a color va lue of 1, any points or lines will be displayed with
the luminance value specified in co lor register 1 and the color in
color register 2. In other words, the luminance of the points and
lines
is affected by the execution of a COLOR 1 statement, but
the color used remains the same as the background color.
The following series of statements illustrate the use of the
COLOR statement in graphics mode 8.
100 GRAPHICS 8
110 COLOR 1
120 PLOT SO,SO : DRAWTO 100,100
RUN
When the
preceding statements are executed, a series of points
will be plotted from position SO,SO to 100,100 with a lumin ance
va lue of 10. These points will be discernable to the naked eye
on the
video display.
If the
following program lin es were then added,
NEW
100 COLOR 0
110 DRAWTO 60,60
RUN
a series
of points wou ld be plotted from position 100,100 to
60 , 60 with a luminance va lue of 4. Since this is the same
luminance as that of co lor register 2 (which was set by the
COLOR 0 statement), the points plotted would be invisible to
the naked eye.
POSITION
Although the graphics cursor is invisible in graphi cs modes 3
through 8, it can sti ll be moved with the POSITION statement.
POSITION is used with the following configuration,
POSITION co lumn, row
where column and row spec if y the screen co lumn and row