>Although when drawing very short lines on a canvas way back when (~2004), it wouldn't do a great job and I had to hack in custom routines that did a much better job.

QCanvas (or was it QGraphicsCanvas?) has long since been replace with QGraphicsScene, which is much more capable and doesn't suffer from pixelation issues.

Probably. We paid thousands / year for the developer seat in our startup, and in the end, it wasn't great. I did manage to make the Tcl/Tk event loop and the Qt event loop work together, so we could have Tk windows inside a Qt app!