Revised font system and other changes

Before attempting new hardware I wanted to finish 2018 with a better, more performant font system and tidy up other loose ends in the code. These changes are now complete. I am now storing fonts as 2bpp bitmaps which allows me to store the outline along with the character data, giving much better performance when rendering in outline mode.

Normally outlining in black is necessary around all character data as well and most graphics, because they tend to disappear against a white or light background. An OSD must be easy to read against any kind of background – you don’t want to have to nose down in order to read the altimeter because it is unreadable against the sky. Now almost everything has a black outline to avoid this problem.

I also implemented a variometer and experimented with yellow-white text and graphics.

I now have a font editor which I will be uploading to Github soon. It is very far from production quality code, simply the bare minimum necessary for me to be able to edit fonts instead of hand-coding them in raw binary as I was doing previously.

Now that these tasks are out of the way I will focus on the new hardware design. I will start by using a genlocked ADV725.