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Fixed distance between visual stimuli regardless of different screen sizes

Hi everyone. I have a visual experiment in which two squares appear on the screen with a specific distance from each other but I don’t want them to differ based on different screen sizes. What can I do to make this distance fixed?

Have a look at my screen scale demo which asks the participant to resize an image on the screen to the size of a credit card.

Hi @wakecarter
Thank you for your reply but what I meant is different. I don’t want participants to adjust sizes and what it to be by default the same size in different screens.

Are you running this online on the participant’s devices or on multiple local devices (e.g. in different labs)?

No I’m running it on participants’ devices. I wanna recruit participants through MTurk so they might have different screen sizes.

In fact I wanna fix the location/ position of my stimuli on the screen. However the size of the stimulus (square) is also important to stay fixed.

This is exactly what my screen scale routine is for.

Sorry What I saw in your experiment we have to alter the sizes but in my experiment I don’t want participants to manipulate anything related to size and location.
Since different people might have different screen sizes I don’t want the distance of two squares stretch out on bigger screens and get closer on smaller screens.
for example I want the distance to be always 5 cm regardless of the screen size.

I will try to explain one more time.

When using PsychoPy online there is no way to know the physical screen size of the device the participant is using.

My screenscale routine asks the participant to resize an image to a known size that is readily available worldwide – the size of a standard credit card.

Assuming that the participant does what they are asked then objects in the experiment can be scaled using x_scale and y_scale so that they are the desired screen size in cm.

Thank you very much @wakecarter and sorry I didn’t get you at first. I used this demo in my experiment and it helped a lot.

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