I already made it. paint.net is too much simple. It has just the trivial. I had a look at gimp source. It's much better than paint.net, but it's still far from what I want. I'm afraid there is no so advanced people doing open source Computer Graphics software. Anyway, I'm still looking for.

Do you know a free Computer Graphics library complex and wide enough to make advanced artistic Computer Graphic effects? Since it's hard to explain exactly what I'm talking about, here you can see the kind of thing I'm would like to be able to make: www.picturetopeople.org[^]. There they say it's all been made absolutely from scratch, but I'm afraid their CG libraries are not open source. Some photo effects you can see in this address are well explained in CG text books, like the dithering, mosaic and warping ones, but there are many effects there I have never seen in books, like pencil, drawing, painting and sketch. About text and pattern effects, maybe it's even harder. They look like drawing with very complex procedural brushes matching directional fields or so. I couldn't find advanced enough explanations to achieve that result level. Is there any CG library able to make all of that?