I presume this will work on the RG35XX+/H/2024/SP, though you may have to adjust the key values based on your device; I only have an RG35XX+ so that's as far as my testing goes.
Blue light from screens interferes with our ability to produce melatonin, a hormone that regulates sleep, resulting in difficulty falling asleep or staying that way. A blue light filter reduces the blue light that a display emits by adjusting the display's color temperature to warmer tones (1900K). It gives everything an amber/yellowish look but it's a small price to pay for better sleep.
While I was looking into this, I also looked into further lowering the screen brightness. Brightness in Batocera is on a 0-255 scale. The Menu + Volume Down key combination lets you lower the brightness by 5% intervals. This means the lowest you can get is 5%, which sets the brightness to 12/255 (5%). So I added in a key combination to drop the brightness down to 2/255 (1%).
Lastly, the RG35XX+ doesn't seem to support holding down keys for repetitive button presses. This is why you have to mash the Volume Up/Down button to continuously increase the volume. The same applies for brightness when using the Menu + Volume Up/Down keys. As such, I added a key combination to jump up to 100% brightness right away - useful in the daytime after playing the night before.
Place them in the following locations:
multimedia_keys.conf-> /userdata/system/configsscriptsfolder -> /userdata/system/configscustom.sh-> /userdata/system
Note: While the custom.sh file schedules the blue light filter to be on between 8:00 PM and 7:00 AM (feel free to adjust these times as you'd like), my RG35XX+ (on Batocera v40 - I haven't jumped to Knulli yet) seems to boot up with a different time displayed before it corrects to my local time. I'm not sure why this happens and any attempts to fix this thus far has been unsuccessful. It started as a +46min difference, changed to a +52min difference, and now it's at +80min. If anyone has any insight as to how I can correct this or what might be happening, I'm all ears.
| Key Combination | Function |
|---|---|
| Menu + Power | Turn on/off the blue light filter |
| Volume Down + Power | Change brightness to 1% (2) |
| Volume Up + Power | Change brightness to 100% (225) |
Yes, the volume buttons mess with your system volume but two clicks to get to 100% brightness (Volume Up + Power & Volume Down) is much better than 19 clicks (5 -> 100 in increments of 5). You can update the keys in multimedia_keys.conf if you want to change these combinations.