Screen resolution in pixels

The grey rectangle represents your screen. By default it depicts a screen with a resolution of 1680 x 1050 pixels (which is a screen with an aspect ratio of 16:10). You can adjust the screen visualisation by entering your screen resolution in pixels.

If you only know the aspect ratio of your screen (e.g., 16:10 or 16:9), but not the exact resolution in pixels, you can enter these numbers as the horizontal and vertical resolutions, respectively. Of course, for pix units, the coordinates shown at the edges of the screen will then not be meaningful, but the other units will still work.

Units

Use the dropdown menu to choose the type of units. Options are height, norm and pix. You can find out more about what these units mean on this page about spatial units in PsychoPy. (The Builder demo “spatialUnits” is also extremely useful to better understand spatial units in PsychoPy.)

Stimulus coordinates

The red dot represents where a stimulus would be anchored on the screen using a particular set of x and y coordinates. By default it depicts a stimulus anchored in the centre of the screen (coordinates [0, 0]). You can adjust this location by changing the x and y coordinates for the stimulus.

If the red dot is not on the grey rectangle, you have chosen coordinates that lie outside your screen. In this case, adjust your stimulus location and/or the type of units you are using.