Quadrant Magnifier

ZOOOOOM!


by Chris Pile





[A Block Line Delete listing by J.M. Clough was printed here. JimG]





Usefulness is simply emanating from these pages this month. I can


barely believe it myself. After the superlativeness of the last


offering we now have Chris Pile and his excellent (and short) Quadrant


Magnifier which'll allow you to zoom in on a specific quarter of the


screen. Wowsers.





Simple Pimple


To get magnifying just type in the self-sufficient, user-friendly


Basic program. Once RUN, this will assemble the code in memory (at


address 63400 incidentally) and SAVE it for you. Cor; some people


don't know how easy they have it. Afterwards NEW the computer to clear


the BASIC away. The code will remain intact.





Zooooom!


First thing to do is specify which quadrant is to be magnified. You do


this by POKEing.a value into address 63401 (0 - Top left, 1 - Top


right, 2 - Bottom left, and 3 - Bottom right). So if you wanted to


magnify the bottom left you'd POKE 63401,2 and so on. Follow up the


POKE with RANDOMIZE USR 63400. A magnified version of that part of the


screen will now fill the entire screen. Repeating this process


produces a sly little zoom effect.