Dynamic increasing of image scale within each trial

Comments

• eduard

  October 2017

  Hi,

  Simple inline_scipt example:

  cv = canvas() # create a canvas
  kb = keyboard(timeout = 2) # create a keyboard
  
  start_r = 10 # initial radius
  rate = 100 # rate of increase
  
  cv.circle(0,0,start_r, fill =True) # draw a balloon
  t0 = clock.time() # starting time
  while True: 
      cv.show() # show the canvas
      k,t = kb.get_key() # stop loop with keypress
      if k != None:
          break
      if (t-t0) >  rate: 
          r += 2
          cv.clear() # wipe the canvas
          cv.circle(0,0,start_r, fill =True) # draw a balloon
          t0= clock.time() # reset timer
  

  Does this make sense?

  Eduard

  
• Eris

  November 2017

  It does if i draw the baloon, but I have to use an image, so basically I have to dinamically zoom in or out the image, using different speed rates.
• eduard

  November 2017

  Well, then use the image draw function with its scale parameter: http://osdoc.cogsci.nl/3.1/manual/python/canvas/#function-canvas46image40fname-centertrue-xnone-ynone-scalenone41

  Eduard

  
• Eris

  November 2017

  Hi eduard,
  I have tried to use canvans.image function, but it still doesn't work for me since the canvas. image do not allowed to present any other stimuli in the meanwhile.
  So I am trying in this way, I create a sketchpad with all the images that i want to present at the same moment, and then I set the scale of the balloon image as a variable , balloon_size.
  The problem is that the var. balloon_size now is a fixed number (i.e. a number that doesn't change its value with time), there is any way to define var. balloon_size Value as a function of time? Exactly like you did in your example for radius? Like for example increase rate of 0.5 every 100 ms?

  Thank you
• eduard

  November 2017

  Hi Eris,

  If you have the scale variable defined in your looptable you, can access it in the sketchpad with [scale].

  However, I still strongly recommend you implement that problem in an inline_script, simply because to make it work with sketchpads it is more difficult to get the experience exactly like you want it.

  I have tried to use canvans.image function, but it still doesn't work for me since the canvas. image do not allowed to present any other stimuli in the meanwhile.

  That isn't true. You can draw multiple images on to the canvas. As long as the bigger one doesn't cover the smaller, you should be able to see all of them. If you give me a few example images and a detailed description of how the stimuli should look like, I can make a quick example for you.

  Eduard