Poor quality of vector images in full screen mode

[thisandagain]

Expected Behavior

Good anti-aliasing

Actual Behavior

Incorrect anti-aliasing

Steps to Reproduce

1.Open Scratch 3.0
2.Click on full screen

Operating System and Browser

Windows 10, Chrome v.68.0.3440.106

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Moved from scratchfoundation/scratch-gui#2847
/cc @SimaKyr

[thisandagain]

@cwillisf This is one of the top pieces of feedback we are seeing in the forums. Let's discuss next week.

/cc @fsih @kchadha @BryceLTaylor @rschamp

[BryceLTaylor]

Her's a great repro of this from the community:
https://llk.github.io/scratch-gui/develop/compatibility-testing.html#230352473

It stamps a white sprite on a white background. I bet it's not actually a problem with the stamping itself, but with the image itself.

It's easier to see if you delete the sprite "Stamped white vector"

[fsih]

@BryceLTaylor I think that might be #237 , not sure if it's the same issue. This one is about an issue going from editor to full screen.

[BryceLTaylor]

@fsih It does seem that it is, I didn't know about the other issue. They do seem related in that they have to do with aliasing.