My first major programs were written under the influence of Knuth—I spent a lot of time reading the source code of TeX and its related programs and learned a lot from that. In fact, I only ever took one computer science class in my life (I went three times and got a C), so I'd have to say that Knuth was by far the most formative influence on my early programming. The other day I was actually looking to see if there was any trace of the DVI previewer I wrote for VM/CMS back in the 80s around on the internet. As near as I can tell, there is not. It'd probably be embarrassing to see (among other things, I didn't do any caching of font bitmaps, mostly because I didn't know how and didn't have time to learn, so every character displayed on screen re-read the bitmap data from disk).
There were two graphic output options in the previewer. There were specialized graphic terminals using the GDDM protocol (this code was actually written by someone in Germany who sent me their changes). The original code that I wrote used Tektronics graphics protocols available in the terminal driver that connected to the mainframe via a protocol converter that enabled the use of cheap ASCII terminals instead of the standard dedicated IBM terminals.
It was an emulation of it on a PC. VT100+Tektronix was a common graphics option on terminals of the era and the PC terminal software provided that as its graphics choice. I had some optimizations like replacing any characters below a certain threshold size with a solid box based on the bitmap's bounding box. It was reasonably fast given the speed of the connection.
