Can I vary the x-y position of the mask on a bitmap?

Hi All,

I’m trying to create a textured visual search target with varying shape. I’m doing this by using a few texture images (2340x1660pixels) and bitmap masks that are relatively small (256x256pixels).

The problem I have is that the mask is always sampled from the centre of the texture. I’d like it to be sampled randomly from within the available bitmap - so that each target is unique. Can I set an ‘offset’ for where the mask samples from?

I’m trying to compile for online, so I’ve limited access to extra code-snippets, unless I add them to the compiled html document.

Best wishes,

George

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OS (e.g. Win10): - windows 10
PsychoPy version 1.85.6
Standard Standalone? (y/n) yes