video fade out

mark

Hi,

I'm using a libet clock method and have the clock working well via prepared canvases (I took the code from the forum). I want the clock to fade out once the participant has responded, but I can't find any way to have an image on a canvas fade away (or to have an arrow drawn on a canvas fade away).

Any ideas?

Thanks,

Mark

eduard

Hi Mark,

How exactly do you present the clock? And what exactly do you mean by fading out? More details on your implementation (description, screenshot, the experiment attached) would be nice to understand what your problem is.

Do you use images, or geometrical forms? As far as I know there is no alpha/opacity parameter for canvases, but in case of images, you could adjust the images outside of Opensesame, and load the ones that correspond to fading out. In case of geometrical forms, you can adapt the colors incrementally such that they become closer to the background, effectively fading out.

Hope this helps,

Eduard

mark

Hi Eduard,

Thanks for your help. The clock was created by calling a series canvases (each with a preloaded image). I was trying to get the clock to continue rotating as it faded into nothing (a field of grey). I was hoping to achieve this fade-out by having the opacity of the images change a bit on each subsequent canvas at the end of the trial. I have done this on PsychoPy (which has an opacity parameter on images) and was trying to replicate it in OpenSesame.

In the end I created multiple fade out-image sequences and had the sequence of canvases switch to the matching fade-out sequence at the end of the trial depending on where the clock was when the trial ended. By having multiple fade-out sequences, the exact start of the fade-out could be randomized (which is what I was aiming for). The only downside is that it requires a lot of coding and preloading a lot of images at the start of the experiment, but it does work.

Thanks for your help!

Mark