Today I just finished my client software to design a t-shirt and the likes. Not sure why she don't just buy legal but cheaper general-purpose graphics software rather than hiring me. Anyway I'm back on pygoocanvas to deal with this basically compositing image software, previously I ever tempted to make usable 2D CAD software that way beyond my ability that time.
Pygoocanvas is really a time safer library should you ever make graphics application based on Python and GTK. With basic animation support (not as robust as clutter though) I can imaged a presentation software would benefit from it. And cairo canvas also make PDF generation a snap. Really like this library!