Re: [Fwd: psychopy: quick and dirty way to draw a square checkerboard]
Jon Peirce
Yes I've forwarded this to the list so that the answer is more generally
seen. The following works on my machine. If you want exactly alternating
pixels over a 128 pixel stimulus then set the cycles to 64 (sf=0.5; half
a cycle of the texture per pixel).
Jon
from psychopy import visual, core
import numpy as np
tex = np.array([[1,-1],[-1,1]])
cycles=4
win = visual.Window([400,400])
stim = visual.PatchStim(win, tex=tex, size=128, units='pix',
sf=cycles/128.0, interpolate=False)
stim.draw()
win.flip()
core.wait(1)
Andre Gouws wrote:
>
> I've tried a few ways of generating a square ware 'square'
> checkerboard (i.e. not radial) patch with fine resolution (i.e.
> alternating pixels
> are black and white) .. can't seem to get the texture perfect though ..
> have tried generating a numpy array and passing it to patchstim as a
> exture .. perhaps I am getting the SF and texRes wrong?
>
> Help appreciated.
>
> A
>
> p.s. would you prefer me to start posting to the psychopy mailing list?
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