Border glitch during resize

[machur]

Hi, I'm using QtInteractor as a plotter being located inside many other Qt Widgets. It looks like there is a glitch of border rendering on resize: when I resize the whole application window, incorrect borders tend to appear randomly for the plotter window and then disappear with further resizing - the issue remains though for many different window sizes. Example with bottom and/or right black borders added below:

I cannot fix it by using stylesheet or setting anything manually. Would you please advice? Is there a workaround?

[machur]

I've observed that this happens on Windows with different scaling set than 100% (tested 125% and 135%).

[larsoner]

Does it happen with 200% scaling? If not I'm guessing it has to do with the fractional scaling sometimes (but not others) making the render area 1px bigger than Qt expects due to rounding errors/differences (e.g., we round while they floor or similar)

[machur]

@larsoner thanks for the quick reply. Yes, it looks like the issue. For 200% scaling there are no artifacts. Is there a feasible way to hack it?

I'm trying to figure out a way around it, hence my discussion #464 - as a workaround I tried to draw some rectangles over the plotter to simply cover the incorrect borders (I'm using wide margins anyway), but it didn't work either.

[larsoner]

Can you try locally changing these to use np.floor rather than round?

pyvistaqt/pyvistaqt/rwi.py

Line 476 in 77be3ec

w = int(round(scale*self.width()))

it might fix the problem, in which case we should make this change here and in the VTK gitlab source

[larsoner]

(or math.floor probably since numpy doesn't appear to be used in that file)

[machur]

I've tested np.floor/np.ceil/np.round and unfortunately the glitch is stilll there.