It is just a demo, but, it shows a lot of fast and thus powerful techniques for manipulating bits on the screen.
I know in my heart that my destination technology is OPENGL or something like it, but, I am enjoying looking under the hood and getting a view of the bare-bones - built up from first principle - programming that has brought us mind-bending graphics engines such as BLENDER.
Here is a screen capture of Franz-Xaver's demo 1, that quickly performs contrast, brightness, color and tint manipulations of the loaded image. The other examples are good too. You just need to run the program again to do so.