Transparent Screen with opaque rectangle

I’m using Matlab in MS Windows to create an experiment. The visual stimulus is pre-made in a web browser and I’m wanting to make the onscreen window in Matlab transparent so that the browser is visible but then have part of the screen covered with a solid rectangle.
I’ve tried the helpful information given by @mariokleiner from a previous post Transparency of Onscreen Window Background - #2 by mariokleiner but I can’t seem to get the onscreen window to be transparent and a rectangle flipped onto that screen to be opaque - the PsychDebugWindowConfiguration function seems to apply the transparency to everything. I’ve tried rearranging the order of the code to create the rectangle first then apply the transparency but this doesn’t seem to work.
Is there a way to apply the transparency only to the screen and then have opaque shapes on top using this function or is at an all or nothing situation?
Any pointers or suggestions as to where I’m going wrong would be greatly appreciated.

me having a look at your issue and possibly giving advice if there is any actionable advice, would require paid priority support. “help PsychPaidSupportAndService” in Matlab/Octave, or the corresponding section on our website.

Happy new year,

Hi kitcat,

I am running into the same issue unfortunately. Did you find a solution in the meantime that you can share? For my program, I want “screen holes” on the left and right side of the screen that I can reveal in a controlled manner (sometimes opaque, sometimes transparent).
Since the transparency doesn’t work neither on Mac nor Windows for me, I tried to just open multiple windows such that I have windows the size of the holes. I would then open a new screen the size of the hole when I want to block the hole and close when I want to reveal the background. The opening and closing of windows is not fast enough for the experiment that I want to run so it doesn’t work for me but might be an option for others. I’m curious if you found something out! Tried to work with Psychopy as well, but didn’t find a way to change the transparency (I’m a beginner with psychopy though)…


Of course @kitcat couldn’t solve that on Windows, given that is wasn’t solvable without my help on modern Windows versions, and kitcat didn’t choose my paid services.

I’m pretty sure PsychoPy or any other software won’t solve this either, given how far they are technically behind PTB wrt. visual stimulation.

Transparency does work on both Mac and Linux, unless you do something wrong or got very unlucky and hit a macOS bug specific to your OS + hardware setup.

My offer for a solution on MS-Windows was in this message in response to you at 1st December last year, which you ignored. Apparently your work time is free, so a 200 Euro christmas offer was deemed too expensive for solving your problem in a timely manner?

The solution still exists, but the generous christmas offer is of course no longer valid, so this would come in at 500 Euros + applicable VAT for a 200 Euros support membership + then buying an extra hour work package for 300 Euros without discounts.

Good luck. Locking this thread.