Mixing psychopy and Canvas elements

Comments

• sebastiaan

  July 2021

  Hi @mattm ,

  Yes, that's possible, although it requires a bit of a hack (and thus may break in future releases of OpenSesame). The trick is to implement your own class that a sketchpad can use as an element, and assign a custom value to the _stim property.

  Like so:

  from openexp._canvas._element.psycho import PsychoElement
  from openexp._canvas._element.element import Element
  from psychopy.visual import Pie
  
  
  class CustomElement(PsychoElement, Element):  
  
      def prepare(self):
        
          self._stim = Pie(win,radius=100, fillColor=[-1, 1, -1 ], start=0, end=90)
  
  
  c = Canvas()
  c['my_custom_element'] = CustomElement(c)
  c.show()
  

  Hope this helps!

  — Sebastiaan

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

  July 2021

  Many thanks, I will use it carefully!
• mattm

  July 2021

  I don't suppose there is a straightforward way to make _stim a compound stimulus, my task is to combine multiple Pie objects into a kind of gauge thing for RT feedback. Of course I could make a separate object for each wedge, but it is not very graceful :]
• sebastiaan

  July 2021

  Hi @mattm , there is, actually. You'd just need to also override the show() method as well 😀

  from openexp._canvas._element.psycho import PsychoElement
  from openexp._canvas._element.element import Element
  from psychopy.visual import Pie
  
  
  class CustomElement(PsychoElement, Element):  
  
      def prepare(self):
          self._stim = [
              Pie(win, radius=100, fillColor=[-1, 1, -1 ], start=0, end=90),
              Pie(win, radius=100, fillColor=[1, -1, -1 ], start=180, end=270),
          ]
        
      def show(self):      
          if self.visible:
              for stim in self._stim:
                  stim.draw()
  
  
  c = Canvas()
  c['my_custom_element'] = CustomElement(c)
  c.show()
  

  
  

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

  July 2021 edited July 2021

  Fantastic! Is there a straightforward way to pass it arguments (e.g., radius)? I suspect more overriding.
• sebastiaan

  July 2021

  @mattm Yes, exactly. You'd need to override __init__() as well. (It might be an idea to implement a more general solution for this, i.e. a way to easily create custom Canvas elements in a non-hacky way. I'll give that some thought.)

  from openexp._canvas._element.psycho import PsychoElement
  from openexp._canvas._element.element import Element
  from psychopy.visual import Pie
  
  class CustomElement(PsychoElement, Element):  
  
      def __init__(self, canvas, radius1=100, radius2=100):
         
          self._radius1 = radius1
          self._radius2 = radius2
          super().__init__(canvas)
  
      def prepare(self):
  
          self._stim = [
              Pie(win, radius=self._radius1, fillColor=[-1, 1, -1 ], start=0, end=90),
              Pie(win, radius=self._radius2, fillColor=[1, -1, -1 ], start=180, end=270)
          ]
  
      def show(self):      
  
          if self.visible:
              for stim in self._stim:
                  stim.draw()
  
  
  c = Canvas()
  c['my_custom_element'] = CustomElement(c, radius1=50, radius2=150)
  c.show()
  

  
  
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