`gl.bmptransparent` not working in Linux

[itellaetxe]

Similar to #62, this option does not seem to work for me either, but in Linux.

I even compiled the latest code as of today (March 2, 2026), but gl.bmptransparent does not work for me. Not even changing it in the options, neither in the advanced options (the .ini file).

Pertinent info:

MRIcroGL 1.2.20241204 GTK2 x86-64 FPC
Linux
Intel; OpenGL= 4.6 (Compatibility Profile) Mesa 26.0.1-arch1.1; Shader=4.60

[neurolabusc]

@itellaetxe unfortunately, this function is at the mercy of the driver support.

You may want to see if you can use NiiVue, for example in a Jupyter notebook. While MRIcroGL relies on the quality of your OpenGL driver, NiiVue uses ANGLE so one would hope it can leverage the Vulkan backend on your hardware.

[itellaetxe]

@neurolabusc thank you for the swift reply, Chris, I appreciate it!

@itellaetxe unfortunately, this function is at the mercy of the driver support.

I was investigating this point a bit and I realized that when I save transparent bitmaps in SurfIce, it does work, no background in the output. AFAIK, SurfIce also works with OpenGL, so SurfIce should also be having this issue... right(?). Why could this be happening? (As you see, I am far from an expert here)

I also tried with the MRIcroGL_QT binary, changing the bitmap zoom to 1, but nothing seems to work.