How can I program an RDK using inline JavaScript?

Comments

• sebastiaan

  July 2020

  Hi @jtdeakin ,

  You can implement this with some creativity 😉 Generating random-dot stimuli in JavaScript won't be possible, but you can generate them offline with Python and then save them as images. Next, you store these images in the file pool, and play them back as an animation by putting a sketchpad inside a loop. (There is a practical limit of about 1000 files in the file pool though. Beyond that browsers start to complain.)

  Saving a frame from a psychopy DotStim , which I assume you're using, isn't trivial, but you can do it by accessing its _verticesBase property like so:

  from PIL import Image, ImageDraw
  import os
  import itertools
  
  SIZE = 200
  DOTSIZE = 3
  
  dots.draw()  # assumption: dots is a psychopy.visual.DotStim
  im = Image.new('1', (SIZE, SIZE))
  dr = ImageDraw.Draw(im)
  for x, y in dots._verticesBase:
      for dx, dy in itertools.product(range(DOTSIZE), range(DOTSIZE)):
          xdx = int(x) + dx + SIZE // 2
          ydy = int(y) + dy + SIZE // 2
          if xdx >= SIZE or ydy >= SIZE:
              continue
          dr.point((xdx, ydy), fill='white')
  im.save('my_dot_stim.png')
  

  Hope this helps!

  Sebastiaan

  
  
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• jtdeakin

  July 2020 edited July 2020

  Thanks Sebastiaan, that is really helpful!