Adjacent quads sometimes slightly overlap

[pstroka]

The problem is only visible when the color of the quad has some transparency. The overlapping quads create a less transparent background.

I found it happening in two situations:

1. when x, y, width or height has a floating point (this isn't a big problem, you can work around it by using floor or ceil when necessary)
   

2. when using fractional scaling (I used 125% here)
   

Note: these screenshots are from my attempt to implement pop-os/cosmic-term#294, the problem doesn't appear in COSMIC Terminal from the master branch.

I guess it has something to do with converting the position/size from float to int.