Make transparent slider Pavlovia (but it appears black)


I’m trying to implement a transparent slider in one of the components of my online experiment. The subjects should not see the slider, but only a white line that I add via an image component.

Because I cannot get rid of the tick lines of the slider (thereby not delimitating values from the slider), I chose to make it transparent and manually add a white line on top of it.

Routine has:

  • slider that should be transparent
  • one image of a white line simulating the slider

In PsychoPy, this works perfectly, but in Pavlovia I can see it as if it’s black, as per below:

Code for slider:

sliderLineDummy = visual.Slider(win=win, name='sliderLineDummy',
    startValue=None, size=(1.5, 0.1), pos=(0, -0.35), units=None,
    labels=None, ticks=(1, 2, 3, 4, 5, 6, 7, 8, 9, 10), granularity=0.0,
    style='rating', styleTweaks=(), opacity=None,
    color='0.0000, 0.0000, 0.0000', fillColor='0.0000, 0.0000, 0.0000', borderColor='0.0000, 0.0000, 0.0000', colorSpace='rgb',
    font=None, labelHeight=None,
    flip=False, depth=-1, readOnly=False)

I could not find an answer on the forum.

Any ideas on how to make this?
Goal is to have continuous slider without ticks on it (so if there is another solution, that would also be great).



I found the following:

From what it states in the solution, a sort of workaround was implemented such that when the color of text, slider or something of the sort is set to color.Util(undefined) , it should be Invisible, by activating an invisibility flag.

However, it does not work for me.

Is there something I’m missing from the solution proposed in the link?
How do I activate the “Invisible flag” ?

Solution link here:

Code for solution direct link here:


For anyone searching a solution, so far I’ve implemented the following workaround:

  1. Launched experiment in PsychoPy locally
  2. Snipped the section that was not properly displayed in Pavlovia
  3. Saved it as an image
  4. Loaded the image as a component in the same routine, positions such as to overlap the (black in Pavlovia) slider

Not actually a solution, but it’s a workaround, hope it helps.