Light pen drawing program

[Bill E]

Based on a short snippet in one of the CHM vids, I've been working on reproducing the line drawing program, can't find the original. It's still a work in progress, but here's what it looks like so far. Note that the original did the pen finder going from bottom up. I didn't like that, so I'm going top down. Travesty, I know.

Bill

[Paul Birkel]

That's so nice!  Why is there a full-pass dot-matrix displayed prior to the one used to find the initial pen position?

[Bill E]

That''s the initial light pen locator. Unless a dot is seen, there is no knowledge of where the pen is. The original does the same.

Bill