Must pixels be specified as integers?

Builder
1

I was wondering if pixels have to be programmed as an integer.

In the example for programming Shapes (psychopy.visual.ShapeStim — PsychoPy v2022.1.0) line width is specified in pixels and the specified value is 1.5

I was wondering how 1.5 pixels can be controlled or if psychopy will automatically round up or down to an integer.

3

Nope! PsychoPy is built on OpenGL and PsychoJS is built on WebGL, both of these allow non-integer pixel values. How this is handled depends on your specific computer setup I think, but you can test it fairly easily like this:

from psychopy import visual, event

win = visual.Window()

# Make one rectangle that's 1px wide, one that's 1.5px wide and one that's 2px wide
obj1 = visual.Rect(win, fillColor="white", units="pix", size=(1, 100), pos=(-100, 0))
obj2 = visual.Rect(win, fillColor="white", units="pix", size=(1.5, 100), pos=(0, 0))
obj3 = visual.Rect(win, fillColor="white", units="pix", size=(2, 100), pos=(100, 0))

# Draw all the rectangles
while not event.getKeys(['escape']):
    obj1.draw()
    obj2.draw()
    obj3.draw()
    win.flip()
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