Round UI coordinates after scaling

[ickshonpe]

Objective

Fixes #9754

Solution

Don't round UI coordinates until they've been multiplied by the inverse scale factor.

[nicoburns]

I think this is probably an improvement in that it brings the rounding later in the process (thus reducing float error). But it looks like this is now rounding in logical coordinates, whereas I think ideally it needs to be done in physical coordinates but after Transform has been applied. Not sure how feasible this is.

[ickshonpe]

I think this is probably an improvement in that it brings the rounding later in the process (thus reducing float error). But it looks like this is now rounding in logical coordinates, whereas I think ideally it needs to be done in physical coordinates but after Transform has been applied. Not sure how feasible this is.

Yes this rounds the logical coords (or it's meant to). I tried a couple of approaches and this one seemed to be the most accurate. By after Transform has been applied do you mean after the GlobalTransform has been computed?

[alice-i-cecile]

@ickshonpe I'll merge this once you fix merge conflicts (I love import merge conflicts...).