[open] Visual Analogue Scale

Comments

• Josh

  April 2016 edited 7:05AM

  Hi,

  Step one is to draw a canvas (similar to sketchpad, see http://osdoc.cogsci.nl/python/canvas/)

  Step two is to collect a mouse response, see http://osdoc.cogsci.nl/python/mouse/

  The mouse response contains a button as well as coordinates, and these coordinates can be used to retrieve your visual analogue scale score. You would just have to determine the coordinates of the scales beforehand, and then calculate to which % the X-coordinate corresponds.

  At some point you'll also want to do some subtle things, such as making sure that a mouse response only counts when it was actually on a scale. Your response collecting command will therefore probably have to be in a while loop, from which you only break when the response was valid.

  Good luck!

  Josh
• Vit27

  April 2016 edited April 2016

  Thanks a lot Josh!

  I'm stacked at the first point. Do I have to create (in Prepare) a canvas for each object (in this case: 3 rectangles, 3 words, 3 lines and 6 words) and ask OpenSesame to show them in the run section, right?
  It shows me the canvas sequentially, not all in the same time. Why?
• eduard

  April 2016 edited 7:05AM

  Hi,

  For all items that are static (that is don't change depending on what you're doing on the screen), you have to use a single canvas. For all other items that do change, you need to add another layer and update it regularly. So, the first canvas, you can indeed prepare in the prepare phase. However, the dynamic layer has to go into the run phase, because the things you're showing (e.g. current selection), will change depending on your behaviour.

  Does this make sense?

  Eduard

  
• Vit27

  April 2016 edited April 2016

  Yes Eduard, it make sense.

  but how can I do that? I've done it, but the rectangles are displayed sequentially not all in the same time. I mean first the first rectangle appear and immediatly disappear, then the second rectangle appears. The same happens to the last one.

  How can I display something like this immage?
  
• Edwin

  April 2016 edited April 2016

  If you want to show three of those sliders at the same time, have a look at this topic: http://www.cogsci.nl/forum/index.php?p=/discussion/827/solved-rating-slider-data-logging/p1

  The solution there is copied below (this should be in the Run phase of an inline_script item):

  # import everything we need
  from openexp.canvas import canvas
  from openexp.mouse import mouse
  
  # create the instances we need
  my_canvas = canvas(self.experiment)
  my_mouse = mouse(self.experiment, timeout=20)
  
  # slider dimensions
  slider_w = 500
  slider_h = 10
  slider_x = self.get("width")/2 - slider_w/2
  # three different y-coordinates, one for each slider
  slider_y = [self.get("height")/4, 2*self.get("height")/4, 3*self.get("height")/4]
  
  # variable names to store the slider fillings in
  names = ["slider_1", "slider_2", "slider_3"]
  
  # questions to put above the sliders
  questions = ["question 1", "question 2", "question 3"]
  
  # loop through all three slider positions, to draw the empty slider canvas
  for i in range(len(slider_y)):
      # draw some text (this can be anything)
      my_canvas.text(questions[i], y=slider_y[i]-100)
      # draw the slider frame
      my_canvas.rect(slider_x, slider_y[i], slider_w, slider_h)
  
  # add a text below the bottom slider, telling participants to click to accept
  my_canvas.text("Click to accept ...", y=slider_y[-1]+100) 
  
  # loop through all three sliders, waiting for input
  for i in range(len(slider_y)):
  
      # keep showing the interactive slider until a click has been made
      clicked = False
      while not clicked:
  
          # determine the slider fill based on the mouse position
          pos, time = my_mouse.get_pos()
          x, y = pos
          slider_fill = min(slider_w, max(0, x-slider_x))
  
          # draw an empty rect within the slider frame, effectively resetting it
          my_canvas.rect(slider_x+1, slider_y[i]+1, slider_w-2, slider_h-2, fill=True, color=self.get("background"))
          # draw the slider fill
          my_canvas.rect(slider_x+1, slider_y[i]+1, slider_fill-2, slider_h-2, fill=True)
          # show the updated canvas
          my_canvas.show()
  
          # Poll the mouse for buttonclicks
          button, position, timestamp = my_mouse.get_click(timeout = 20)
          if button != None:
              clicked = True
  
      # save the slider's filling
      slider_percent = 100.0*slider_fill/slider_w     
      self.experiment.set(names[i], slider_percent)
  
• Vit27

  April 2016 edited April 2016

  Thanks Edwin!
  This is amazing and really useful and it works well! But what if I would to let participant chose to answer just to one of these three sliders, and not to each one sequencially? Should I add a mousetrap to let the mouse visible?
• Vit27

  June 2016 edited 7:05AM

  Hi Edwin,
  In my output I cannot find any variable with slider_percent. I ust say that I inserted a logger not immediatly after the inline script, but in the end of the trial.

  Anyone can tell me why?
  # save the slider's filling
  slider_percent = 100.0*slider_fill/slider_w
  self.experiment.set(names[i], slider_percent)