how to record distance between a fixed point and where the participant clicked.
I am trying to build a relative size judgement task where participants will be asked to estimate the height of the goalkeeper (example image attached).
Participants will be asked to click on the pole where they believe the goalkeeper's height would be relative to the soccer ball. With classic mouse function, it only records the coordinate (x,y) relative to the whole screen rather than the distance from the bottom bar to the point they clicked.
I purposely do not align the bottom bars (or else relative size judgement becomes too easy). And I would like to change the location of the target stimulus and response stimulus time to time.
If anyone knows how I can record distance between a fixed point (i.e., bottom bar) and where the participant clicked, then it would be a lot of help if you can give me some advise.
Thank you very much for your time.