Propeller Clock Advanced Design

[Balachandar]

I am one of those countless PIC enthusiasts to have been fascinated by the Propeller Clock, first popularized by Bob Blick. I built my first propeller clock in Nov 2004 using PBP for coding. It was a fairly simple design with 7 LEDs for character display, one LED for the outer ring under software control and an IR remote control. Then in Aug 2007, I improved the design to have a 16 LED 2-line display with time, date and alarm features (Photograph attached).

Recently, I came across an amazing design. Link:

Characters that are displayed in a system that use spinning LEDs become larger as they go away from the centre. In other words, they flare out. What is unusual in the above design is that the images and characters appear as if they are displayed on a regular monitor. They claim, “Real time Cartesian to Circular Graphics Conversion”. How is it done in software? What is the algorithm used? Do I need to do a crash course in Trigonometry and Linear Algebra?

I would highly appreciate any explanation, pointers, help or guidance so that I can start experimenting.

Thanks & Regards,
Bala