I really can't visualize what kind of program you're describing.

A program that draws things on a window and then queries those drawings or widgets... Do you mean for instance; the position of a line on the canvas, the state of a button (clicked, raised, lowered, active...). Perl/Tk is very good at that kind of thing. Perl/Tk is not a program ofcourse, it's a toolkit for writing GUI programs with.