Note: There is no shame in old bad code. So I'm open sourcing this even though it's not useful for anyone.
I used to play around with X11 programming a lot. I tried my hand at making a canvas library that would allow me to build UI widgets that I could use to make applications. I was a terrible programmer who makes terrible decisions, so I decided to write it in C++.
This was written a long time ago, it's totally unsupported, unusable, without merit, and laughably implemented.
As of 02/27/2010, it compiles and runs on snow leopard. I'm 100% sure it would still work on Linux as well.
You'll need an c++ compiler, x11 libraries and imlib2. On linux, you should have all of those... you may need to install imlib2. On a Mac, install the x11 SDK (from the xcode stuff) and then use ports or something to install imlib2 sudo port install imlib2
There is no install. Run make
then ./canvastest