Prevent canvas auto destruction

[GavinStark87]

I have a task with many trials. Those trials display different images on a canvas but have several elements that for the most part stay the same. The problem is that because the canvas is destroyed between trials there is a flickering effect on lower end devices as the canvas is blanked and needs to redraw itself. On the elements that change more dramatically this is less noticeable but on the others, especially if the user is going through the task quickly, it can be a bit distracting. Is there a way to prevent the destruction of the canvas and allow me to manage the canvas entirely?

[kurokida]

Hi, I’ve had the same issue before.
I’m the author of the psychophysics plugin, which had the remain_canvas property up to version 3.7.0.
I’m not sure if my plugin will solve your problem, but feel free to give it a try.

You can download it from https://github.com/kurokida/jspsych-psychophysics/archive/refs/tags/v3.7.0.zip.
After extracting the zip file, please check remain_canvas.html inside the psychophysics-demos folder.
On line 59, you’ll see remain_canvas: true,. If you comment this out, there may be a blank interval right before the black circle starts moving (which is probably the issue you want to eliminate).

Please note that even when remain_canvas is set to true, you still need to draw all stimuli for every trial.
I hope my plugin will be helpful to you.

Best regards,
Daiichiro