Animations bug - leaving border marks when zoom is not 100%

I have encountered a problem with view size animations leaving border lines when moving around. I was dealing with this issue in the past in some demo, but it “dissappeared” later so I didn’t worry about it.

Turns out the problem dissappeared, because I was using bitmaps with transparent border offset, so it was not visible. But if I use a different image as a background for a CViewContainer which I am moving around with animation, it leaves lines when the zoom is not 100% until the view under the moving one is marked invalidated again.

I am guessing it is some rounding issue, that tells the view which rectangle to redraw?


The whole video is here

Which version of VSTGUI are you using and do you like to tell us what platform you’re on? Windows, macOS? And which version of it?
Looks like that the clipping rectangle and the rendering rectangle are not in sync.
But as you already have find out yourself, it will work if you leave some transparent pixels as margin in your image assets.

I am using the VSTGUI 4.9.
The video was taken on Windows 10. It also happens on macOS (using 10.15.7) but weirdly enough, it is visible on native macbook retina display, but not on external non-retina monitor.

And also does not happen when zoom is 200%.

Yeah, zoom factors that are multiples of 100 won’t produce errors as there won’t be any rounding issues.
What you can do is to make sure that when you do the automation, that you make sure that the view’s frame coordinates are always on pixel boundaries.