Converting Eyelink / Pygaze coordinates to be "compatible" with OS coordinate system

[sa-al-ja]

Hi there,

I have a question about how to "convert" the coordinates of my eyetracking data that has been collected with PyGaze and the eyetracker EyeLink 1000 Plus.

Since I would like to "convert" my data into the Open Sesame system, I wanted to confirm that the following information is correct:

• Pygaze coordinates: top left is origin of coordinate system (0,0)
• OS coordinates: (0,0) is in the center of the screen

So from what I found online, to "convert" the Pygaze data to be compatible with the OS coordinate system, is it the correct approach to subtract half the width and height from the gaze position from the Eyelink data?

So, if I take one example datapoint from EDF Eyelink file:

x: 954.3, y: 529.8

Following this logic, I would divide both by 2 to get the following coordinates that are then "compatible" with the OS coordinate system?

x: 954.3 / 2 = 477.15
y: 529.8 / 2 = 264.9

Thanks a lot in advance!

Best,
sa-al-ja