Gratings with circular mask have artefact lines (high contrast) on some browsers

[michaelbach]

When displaying gratings with a circular mask, artifact lines can occur in the grating. It’s actually a defect of the browser, and does not occur on all browsers: Some browsers (specifically Safari) cannot copy correctly with clipping regions.
Possible solutions / workarounds:

• Wait for improvements in the browser
• Don't use Safari
• Coding solution: Emulate the mask by calculating each line length separately, obviating the clipping. I don't see me doing that any time soon.