Using VNC as a graphics library

VNC's protocol, Remote Frame Buffer (RFB) is a fairly sane way to stream graphics and to receive keyboard and mouse events. A graphical application can theoretically be implemented as an RFB server, using no libraries except libc and libz. This is a simple demo of how such an app would work. Currently, it doesn't accept any user input, but just streams frames of a solid color rotating through the HCL color space (which I devised and implemented for other projects). I also haven't tested it with many implementations of VNC, but to my knowledge it conforms to the RFB 3.3 specification, so any conforming viewer should work.

$ make
$ ./color_rotate_zrle &
$ vncviewer localhost::4092

Future work:

• Split out encoding to a send_rect function
• Parse client messages
• Provide user input handlers
• Consider an SDL backend: same send_rect and register_handler likely apply
• Implement a box model to route user input to interface elements
• Implement font rendering with FreeType
• Implement TeX+TikZ style graphics (big job)
• Create useful interface elements for this platform