Distorted Scroller

DISTORTED SCROLLER


by Rick O'Neill





Oh blimey, surely not another scroller? But wait! This one's a real


cracker. Not only does it scroll the message of your choice across the


middle of the screen, but it also wobbles it up and down and ripples


rainbow colours across it. All at the same time. (Now I can see you're


interested.) It's been written by none other than Rick "I've Got The


Scrolls Real Bad" O'Neill, the chap who wrote Swiss Scroll back in the


June issue. He's obviously into these things pretty heavily.





The Procedure


The program's an absolute doddle to get working. Just type in the


Basic listing (using stars or something instead of those funny


crossed-out 0s in lines 120 and 130 - they're just my printer being


crap) and SAVE "SCROLLER" LINE 10. Now load up the Hex Loader and use


it to type in the hex listing, specifying 64512 as the start address


and SCROLLER as the filename. Save the resulting code after the Basic,


reload it and watch the amazing demo. Not bad at all, eh?





To use the scroller in your own programs, all you have to do is put


the string you want to scroll into L$ and RANDOMIZE USR 64512 to "hit


it". As well as the usual letters and numbers there are three special


characters you can use ...





CHR$ 124 - This pauses the scroller for half a wave, leaving the message


bouncing up and down. Multiple use will allow you to stop it for as long


as you like.


CHR$ 255 - Repeat from the beginning.


CHR$ 0 - Stop. The scroller can also be halted by pressing Space, except


when it has been paused with CHR$ 124.





Line 105 in the Basic program contains the variable BOLD. Setting this


to 0 turns bold off, and setting it to 1 turns it on. And if you don't


like what happens to the colour, POKE 64680,201, and with 33 to turn


it back on. Address 64686 holds the speed of the colour cycling, which


is initially set to 5.