I’ve been experimenting with incorporating the geometry and math library Cindy.js into OpenProcessing sketches. That works ok, but I don’t seem to be able to make preview-thumbnail screenshots when I show a 2D colorplot. It does work fine when I simply show an x,y plot.
Weirdly, I was able to make thumbnail screenshots, and indeed thumbnail videos, just a couple of weeks ago. E.g. this one: https://openprocessing.org/sketch/2703546
Did something change recently in the way OpenProcessing makes thumbnail screenshots?
In you html file you have </body tags but that would not cause the issue.
I tried many ways to get a thumb nail and eventually I did manage it, check out my sketches here
I am not sure how I did it but when I tried your sketch I got the message
InvalidStateError: CanvasRenderingContext2D.drawImage: Passed-in canvas is empty
and the screen froze during the capture and I could not get back to the code view without refreshing the browser window. I also tried a video thumbnail.
Eventually I had the old plot nail in my sketches window but when I opened the sketch and went to edit the color nail was there so I submitted the edit again and it appeared to work.
I am not sure exactly the procedure because it was all hit and miss but at least you know it is possible
