Video Output Control
by P.R. Dick


Editor's Note: This article originally appeared in the Jan/Feb issue of AUGment, vol. 2, no. 2, page 8.

The following POKES can add professional appeal to your own projects and can even enhance some commercial software. First, note the color codes (4-15) in the July August AUGment. Next, let's explain my variable names:

bs = background color
il = inverese letters
nl = normal letters
gw = graphics window
is = inverse screen
ns = normal screen

TEXT mode POKES:

POKE 17059, bs  (default = 0)
POKE 17115, nl*16+ns  (default = 240)
POKE 17126, il*16+is  (default = 15)

GR mode POKES:

POKE 18607, bs  (default = 1)
POKE 18633, gw*16+gw  (default = 17)
POKE 18711, nl*16+ns  (default = 240)

HGR mode POKES:

POKE 25431,bs  (default = 1)
POKE 25471,gw*16+gw  (default = 17)
POKE 25568,nl*16+ns  (default = 240)

None of these POKES affects the other modes, so you can have color in all three. To implement the color change, just type the corresponding mode command (TEXT, GR, or HGR) and press <RETURN>. Note that "0" is transparent; it is not "black." Also, FLASH, in the TEXT mode, is the result of alternating between NORMAL and INVERSE colors. Finally, the HGR POKES will work in HGR2 with the exception of the text window.

You can change the prompt, cursor or HOME blank space character by poking the new ASCII value into addresses 1146, 16953 and 16954, respectively.

You can use any of the 16 colors in HGR mode, poking the color code into address 16777. Also, you can reset the current device by poking the new value into 16641 (d1=8, d2=24, d3=4, and d4=5). Finally, you can increase the graphics text window to 8 lines with POKE 16958,16 and POKE 16993,8 and POKE 16995,16 and then typing HOME. (Changing modes will reset these addresses to their default values).

P.R. Dick
Data Doctor
P.O. Box 776
Oak Hill, WV 25901

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