Set specific clickable area

If this template helps then use it. If not then just delete and start from scratch.

OS (e.g. Win10): Win10
PsychoPy version (e.g. 1.84.x): 2022.2.5
Standard Standalone? (y/n) If not then what?: Yes
What are you trying to achieve?:
I’m trying to make only the color band on the scale (image below) to be clickable.

What did you try to make it work?:
I cropped out the color band (as a new image) removing the background, and make it perfectly overlap with original one, so it look like a same image but it is actually two (scale.png and colorband.png).

In code

mouse.isPressedIn(colorband):  do something.

What specifically went wrong when you tried that?:

Even if I remove the background, the color band is considered by PsychoPy as a rectangle image with the same with and height. What I thought was just the color band.
So not only the color band is clickable, but the inner circle as well, which is not what I wanted.
Include pasted full error message if possible. “That didn’t work” is not enough information.

I would make a transparent polygon as the same shape as the color band and overlap with it. But it is difficult to figure out the parameters to use to make that shape.

Any ideas, help? thanks in advance.
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