Present one image on the top of another

Description of the problem:

PsychoPy version: 2021.2.3
Standard Standalone? (yes)
What are you trying to achieve?:

  • I have two images working as background (image 1 and image 2). And one object (image 3) will be moving from the bottom to the top, as if it comes out of the box. It works perfect locally because I can arrange the three images very easily. However, when it goes to pavlovia, the bottom image is presented behind the object (image 4). I am wondering if there is an easy way to present the bottom image on the top of the object. Thank you so much!

image 1

image 2

image 3

image 4

The key to doing this online is to make sure that the foreground is being updated every time the background changes. I either alternate the opacity between.98 and .99 or move it up and down by a pixel.

Hi @wakecarter, thanks so much for your quick reply! Could you please give me more instruction about how to alternate the opacity? Do you mean that I need to update the opacity of the object (image3) every frame? Thank you so much!

It’s image2 you need to keep in front.

The following might work


You might be able to put 1-.01*frameN%2 in the image component instead of in code.

If opacity doesn’t work, try doing the same to the x coordinate.

Sorry for the late reply! THank you so much for your help, I really appreciate it.