Msg: 5119 *Conference*

06-13-94 23:38:42

From: COMET _

To : CHARLES CLARK

Subj: REVERSE-VIDEO

The reason you don't see the inverted white-on-black characters in your ASCII
table, is because the inverted characters have the exact same code as the
black-on-white characters.  The only difference is the screen attribute.  To
set reverse video mode, output an ESCape character (ASCII 27) followed by a
lower-case "p" (ASCII 112).  Any printable characters will now display in
reverse-video.  To reset this mode back to normal, output an ESCape character
followed by a lower-case "q" (ASCII 113). 
 
Here is a sample BASIC program:

 10 RV$=CHR$(27)+"p":REM Reverse video
 20 NV$=CHR$(27)+"q":REM Normal  video
 30 PRINT RV$;"Reverse Video!";NV$
 40 END:REM Demo program by Comet, 1994
 
This will write "Reverse Video!" in white-on-black characters. Note that I
reset the screen graphic rendition back to normal. I used the CHR$(27), since
ESCape is not a printable character. 
 
Now that you are aware of the fact that the Model 100 knows escape sequences,
you are probably wondering about the rest. I'm new here, so I'll leave it to
somebody else to point out where these things are documented here, and to
demonstrate the machine language CALLs that perform the same tasks.