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The Basics of BASIC
by Rick Burton (RACE)

To further explore "graphic illustrations" of the characteristics of color,
this month we will start to tie the SETCOLOR and COLOR commands together. Be
patient enough to read carefully AND type example demos as you go. Soon you
will appreciate 8bit capability and become a real painter of pixels.

Last month we saw that SETCOLOR is followed by three numbers separated by
commas. The first number was used to select text, border, and background. From
now on, we will call this the register number or SETCOLOR register. Each
SETCOLOR register contains "default" colors and brightness. Registers are
numbered 0 to 4. Using GRAPHICS 3 as an example, the following is a run-down
on these registers:

     SETCOLOR 0: contains orange- access with COLOR 1

     SETCOLOR 1: contains light green- access with COLOR 2

     SETCOLOR 2: contains dark blue- access with COLOR 3

     SETCOLOR 3: not used in GRAPHICS 3

     SETCOLOR 4: contains black- access with COLOR 0 (also
controls background)

 Notice that the COLOR command can access SETCOLOR registers! The great
COLOR/SETCOLOR connection! Different COLOR commands can be used at the same
time to draw different colored lines on your monitor. The desired color
command precedes the line or lines to be drawn that color. Confused? Fire up
that 8bit and type this:

     10 GRAPHICS 3+16      20 COLOR 1      30 PLOT 8,2      40 DRAWTO 8,22
50 COLOR 2      60 PLOT 20,12      70 DRAWTO 20,22      80 COLOR 3      90
PLOT 32,8      100 DRAWTO 32,22      110 GOTO 110      120 END

 There you have it -- a simple bar graph. Compare the SETCOLOR register chart
with the commands found in the demo program. COLOR 1 accesses SETCOLOR 0
(default orange), COLOR 2 accesses SETCOLOR 1 (default light green), and COLOR
3 accesses SETCOLOR 2 (default dark blue). Now lets stir up a new color on our
artist's palette. Change SETCOLOR register 1 by typing:

     55 SETCOLOR 1,5,6

 Run this demo with the new program line.  When the paint brush is dipped in
COLOR 2, out comes violet!  (See last month's Basics for details on SETCOLOR
and a color table.)

A last note -- line 15 from last month should have read: 15 FOR X=1 TO 14 STEP
2.  Apologies for the typo.  We'll see all you 8bit artists next month for
more "graphic illustrations" of the characteristics of color...