How to set grayscale color (value:0-255) shapes in Opensesame?

Comments

• sebastiaan

  March 2024

  Hi @Ornella ,

  Is your question about what kind of units psychopy (by default and in the context of OpenSesame) uses for color specifications? These are on a -1 (black) to 1 (white) scale, so if you have values on a 0 (black) to 255 (white) scale you'd convert them as follows:

  psychopy_color = (my_color - 128) / 128
  

  Does that clear things up?

  — Sebastiaan

  
  
  Check out SigmundAI.eu for our OpenSesame AI assistant!
  
• Ornella

  March 2024 edited March 2024

  Hi @sebastiaan,

  Thanks for your help! I just want to draw grey circles of different lightness(I don't know if I'm phrasing this correctly?). So can I set the Circle.color to a value between -1 and 1, like this?

  stim_size = 100
  my_color = random.randint(0, 255)
  gray_scale = (my_color - 128) / 128
  cnvs += Circle(x, y, stim_size/2, color=gray_scale, fill=True)
  

  But I noticed that no matter what the value of Circle.color is between -1 and 1, I get black circles (see figure below). Have I misunderstood? I look forward to hearing your answer.

  

  
  
• sebastiaan

  March 2024

  Hi @Ornella ,

  Ok, I see. The Circle() class in OpenSesame is not the same as the psycho.visual.Circle() class, hence the confusion. (The first is to draw on an OpenSesame Canvas object, the second to draw on a PsychoPy window object. They are conceptually similar in that they both draw a circle, but they do so in a different context.)

  You can see how to specify colors in OpenSesame here:

  https://osdoc.cogsci.nl/4.0/manual/python/canvas/#colors

  One way is actually to simply specify an integer between 0 (black) and 255 (white), which seems to be exactly what you need:

  cnvs += Circle(0, 0, 50, color=0, fill=True)  # black
  cnvs += Circle(0, 0, 50, color=255, fill=True)  # white
  

  Hope this helps!

  — Sebastiaan

  
  
  Check out SigmundAI.eu for our OpenSesame AI assistant!
  
• Ornella

  March 2024

  Hi @sebastiaan,

  That works! Thank you very much!🤗🤗