Loading png overlay with command line

Nash

Hello,

I need to add a custom png in front of a port game launched with my own script with xinit. I need to to the same job as Retroach's overlays but I don't find the command or the program used.

It should be easy to load a png into a system that does it everywhere, but I'm stuck.

mitu

I'm not aware of any general method of overlaying an image on-top of a runing program, but you can set the background using feh and have the port's window fit in the middle.

Nash

@mitu Thanks but I really need to add png over to hide some undesired window elements. And it will be useful later for me to do some OSD on anothers projects.

Nash

So nobody can tell me how to load png overlay with something already present in Retropie ? I would like to avoid adding another third-party program unnecessarily. Even that is hard to find.

It drives me crazy, there are PNG loads absolutely everywhere with OSD displaying png or animations everywhere like widgets. I looked in the Retroarch source code but I didn't find anything in what I can understand.

I don't find anything on the web. How did devs have learned to display PNG ?

sleve_mcdichael

@Nash i found this Reddit post https://www.reddit.com/r/linux_programming/s/AUs0i0Hhis

In in it they suggest using pngview (https://github.com/AndrewFromMelbourne/raspidmx/tree/master/pngview), or suggests that also you can write directly to /dev/fb0 (https://seenaburns.com/2018/04/04/writing-to-the-framebuffer/)

Nash

@sleve_mcdichael It looks like very hard consisting to draw every pixel in a framebuffer. It should be existing something at easier level like "function load" '/home/pi/img/png.png' at "coord x" and "coord y" usable in a script.

For instance EmulationStation themes are looking for load border.png, or pop games videos in front of everthing. I doubt the dev must code "draw each pixel in framebuffer" everytime. They call certainly existing commands avaiable in the OS environement.

I will try pngview.

Nash

Ok, pngview was already installed on my system and used by the PiBoy OSD. I found a png loading used in the installscript of the firmware and I can reproduce this when I want with a single line added in my scripts. It's exactly what I was looking for !

@sleve_mcdichael Thanks for your help