Objects sometimes translate when flipping

[ericwa]

1. Start with the default map, and add this brush:
   
2. Select both brushes and press Cmd+F to flip them. This is the result:
   
   The brushes have been translated a bit on the X axis. Is TB grid-aligning the center point of the entire selection before flipping it?
   It might be better if things didn't shift like this when flipping.

[kduske]

It is in fact grid aligning. Not sure if not doing that is better or worse. I did it to avoid floating point problems. I could however just snap the point to int to achieve the same.

[ericwa]

Hm.. I think the safest thing would be not rounding at all here. Any floating point errors will be tiny since it's all double precision.

Also, rounding the center point to integer before flipping could introduce 1 unit offsets, in the same way as my example does, which would be difficult to see.

[kduske]

Well it might turn integer plane plane points into float, which I'd prefer to avoid.

[ericwa]

How about rounding the bounding box min/max points to integers before taking the center point?

This will give a center point that is either integer, or an integer +/- 0.5. Those should be safe floating-point values; 0.5 is not a repeating fraction in binary like 0.1 is.

I've got a PR for this I'm just polishing up.

[ericwa]

Fixed now that #1500 is merged