Plotter: the first screenshot is blank + image quality issue

Hi, I have stumbled into an issue with screenshooting today. Minimal example:

import vedo
vedo.embedWindow(False)

corners = [[-20,-20], [20,20]]
plane = vedo.shapes.Rectangle(*corners, c='lightgrey') # alpha<1 makes it immediately invisible when looking from above
sphere = vedo.shapes.Sphere(pos=(0,0, 10),r=2)


plotter = vedo.plotter.Plotter(axes=7, interactive=False)
plotter.add([sphere, plane])
plotter.show()
plotter.screenshot('test.png') 
plotter.screenshot('test2.png') 
plotter.close()

• The first screenshot is just blank, the second is saved normally.
• Same with vedo.io.screenshot (both when saving to file or to a numpy array).
• My OS is Windows. I use the latest version vedo 2020.4.0.
• Same behaviour from jupyter notebook or a script.

The second issue is that the screenshot, generated with offscreen option seem to have conisderably lower quality. For now I am just going to not use this option, but I was just surprised by this behaviour.

Cheers, icemtel

[DeepaMahm]

If I run your example with interactive=0, then the screenshot is blank, with dark-grey color (before is was all white).

I had the same issue and it helped after installing vtk version 9.0

[icemtel]

@marcomusy I think “team discussions” and “discussions” are different things (confusing indeed!). Perhaps github discussions are still in beta and you should ask to enable it here? https://github.community/t/can-one-apply-for-github-discussions-beta/121120/2