In a follow-up to my recent post about Vaughn Cato’s 3-D vector maze test for the Radio Shack Color Computer 3, there was another bit of code he sent me: a bitmap scaling test. He created a routine that would take a bitmap graphic then render it on the screen at a different width and/or height. I forget why I was interested in this topic back then, but I do know I have blogged about “scaling” on the CoCo in recent years on this site.

Here is a video of his mapgraph test program running:

The routine appears to use 6809 assembly language and C code. The idea would be you could have a bitmap image then place it on the screen at different sizes. This demo just loops “stretching” a test pattern image, but the graphic could have been anything.

One more post to come…