Hi,
I modified a script for a visual search paradigm where 6 pictures are displayed in a circle around the fixation cross. The size of the circle is now based on the height and width of the display (I think).
How can I choose the size of the circle despite the monitor size? I'd like to try with a fixed size of the circle because the experiment will run online and I cannot control for the display of the participant.
If there is a specific reason why I should NOT keep the circle size constant, please tell me.
This is a part of the code that should be relevant, more or less, I can provide more if needed.
Thanks,
Francesca
--some of the parameters--
<parameters>
/ trialnumber = 120
/ practicetrials = 12
/ fontsize = 10%
/ fontsize_fixation = 5%
/ pictureheight = 15%
/ radiusscreenproportion = 0.4
/ readyduration = 100
/ blankduration = 200
</parameters>
-- an example of picture selection --
<picture target>
/ items = targets
/ selectionrate = always
/ select = values.target
/ size = (100%, parameters.pictureheight)
/ position = ( 1px * values.target_x, 1px * values.target_y)
</picture>
----------------------------------------------------
Calculate circle coordinates
----------------------------------------------------
<expressions>
/ xcenter = 0.5 * display.canvaswidth
/ ycenter = 0.5 * display.canvasheight
/ radius_Circle_px = parameters.radiusscreenproportion * display.canvasheight
/ Radians_Circle_angle0 = rad(0)
/ Radians_Circle_angle60 = rad(60)
/ Radians_Circle_angle120 = rad(120)
/ heightchange_Circle_angle0 = sin(expressions.Radians_Circle_angle0) * expressions.radius_Circle_px
/ widthchange_Circle_angle0 = cos(expressions.Radians_Circle_angle0) * expressions.radius_Circle_px
/ heightchange_Circle_angle60 = sin(expressions.Radians_Circle_angle60) * expressions.radius_Circle_px
/ widthchange_Circle_angle60 = cos(expressions.Radians_Circle_angle60) * expressions.radius_Circle_px
/ heightchange_Circle_angle120 = sin(expressions.Radians_Circle_angle120) * expressions.radius_Circle_px
/ widthchange_Circle_angle120 = cos(expressions.Radians_Circle_angle120) * expressions.radius_Circle_px
</expressions>
----------------------------------------------------
Circle coordinates positions
----------------------------------------------------
<list x_coordinates_pictures>
/ items = (expressions.widthchange_Circle_angle0,
expressions.widthchange_Circle_angle60,
expressions.widthchange_Circle_angle120,
-expressions.widthchange_Circle_angle0,
-expressions.widthchange_Circle_angle60,
-expressions.widthchange_Circle_angle120)
/ replace = false
/ selectionrate = always
</list>
<list y_coordinates_pictures>
/ items = (expressions.heightchange_Circle_angle0,
expressions.heightchange_Circle_angle60,
expressions.heightchange_Circle_angle120,
-expressions.heightchange_Circle_angle0,
-expressions.heightchange_Circle_angle60,
-expressions.heightchange_Circle_angle120)
/ selectionmode = list.x_coordinates_pictures.currentindex
/ selectionrate = always
</list>