Slider widget in Expyriment

Comments

• fladd

  September 2017

  Hi anapinho,

  not a slider widget, but a similar solution that works with radio buttons:

  #!/bin/env python
  
  """ A radiobutton example in Expyriment."""
  
  __author__ = "Florian Krause <florian@expyriment.org>"
  
  
  from expyriment import control, stimuli, misc
  
  
  control.set_develop_mode(True)
  exp = control.initialize()
  exp.mouse.show_cursor()
  
  question = stimuli.TextScreen("The answer to life, the universe and everything?","")
  question.present()
  question.present() # Twice for double buffering!
  
  answers_pos = [["1", -300], ["2", -200], ["3", -100], ["42", 0], ["7", 100], ["99", 200], ["100", 300]]
  
  answer_canvas = stimuli.Canvas((700, 200))
  answers = []
  buttons = []
  for answer in answers_pos:
      a = stimuli.TextLine(answer[0], position=(answer[1], -30))
      a.plot(answer_canvas)
      b = stimuli.Rectangle((20, 20), line_width = 2, position=(answer[1], 0))
      b.ticked = False
      b.plot(answer_canvas)
      buttons.append(b)
  
  answer_canvas.present(clear=False)
  answer_canvas.present(clear=False)  # Twice for double buffering!
  
  tick = stimuli.Rectangle((10, 10))
  tick.preload()
  
  untick = stimuli.Rectangle((10, 10), colour=exp.background_colour)
  untick.preload()
  
  while True:
      exp.keyboard.check()  # Press ESC to exit
      if exp.mouse.check_button_pressed(0):
          exp.mouse.wait_press(0, wait_for_buttonup=True)
          pos = exp.mouse.position
          for button in buttons:
              if button.overlapping_with_position(pos, mode="surface"):
                  if button.ticked:
                      button.ticked = False
                      untick.position = button.position
                      untick.present(clear=False)
                      untick.present(clear=False)  # Twice for double buffering!
                  else:
                      button.ticked = True
                      tick.position = button.position
                      tick.present(clear=False)
                      tick.present(clear=False)  # Twice for double buffering!
  
  

  You could modify it to work with the keyboard instead of with the mouse.

  Hope this helps!

  Warning There was an error rendering this rich post.
• anapinho

  October 2017

  Thank you for this. In the end, I decided for a different solution but I will keep this for the future.
• PMKraemer

  April 2018

  Hello anapinho,
  would you be so kind to tell how you did it? I'm facing a very similar problem than you did. Would be super helpful to get some idea
• PMKraemer

  May 2018

  okay I've approached my problem for a willingness-to-pay task for a snack like this:

  #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  """
  Created on Wed May  9 17:20:15 2018
  
  @author: peterkraemer
  """
  
  from expyriment import control, stimuli
  
  #control.set_develop_mode(True)
  
  exp = control.initialize()
  ######################  STIMULI  ######################
  #   creating elements on screen
  
  # picture
  path_picture =   '/Users/peterkraemer/Desktop/experiment/PICTURES/snack1.bmp'
  picture      =   stimuli.Picture(path_picture, position=(0,200))
  
  # bar
  barLength = 300
  barThick = 10
  posBar=(0,-100)
  bar = stimuli.Rectangle((barLength,barThick),corner_rounding=None,position=posBar)
  bar.preload()
  barEndLeft = stimuli.Rectangle((5,barThick*3),position=((-(barLength+2)/2), posBar[1]))
  barEndLeft.preload()
  barEndRight = stimuli.Rectangle((5,barThick*3),position=(((barLength+2)/2), posBar[1]))
  barEndRight.preload()
  
  # slider
  posSlider = (0,posBar[1]) # initial position of the slider
  
  # sliding function
  def sliding(pos,commit):
      while commit==0:
          # create a composition to show multiple elements at the same time
          composition = stimuli.BlankScreen()
          picture.plot(composition)
          bar.plot(composition)
          barEndLeft.plot(composition)
          barEndRight.plot(composition)
          slider = stimuli.Rectangle((3,30),position=pos, colour = (194, 24, 7))
          slider.plot(composition)
          composition.present()
          # participants can use left and right arrow to adjust slider position & commit with enter
          key, rt = exp.keyboard.wait(process_control_events=True)
          if key == 13:
              commit = 1
              return pos[0]
          elif key == 275:
              pos = (pos[0]+10, pos[1])
              if pos[0] > barLength/2: # fixes upper end of the scale
                  pos = (barLength/2,pos[1])
          elif key == 276:
              pos = (pos[0]-10, pos[1])
              if pos[0] < -barLength/2: # fixes lower end of the scale
                  pos = (-barLength/2,pos[1])
  
  # position - money translation
  scaleMax = 5 # upper end of the scale
  moneyPerPixel=scaleMax/barLength # = CHF/Pixel
  
  ## start ##
  control.start(exp,skip_ready_screen=True)
  
  val = (sliding(posSlider,0)-(-barLength/2))*moneyPerPixel
  print(val)
  
  ## end ##
  control.end()
  

  certainly not the most elegant way but anywayne