[FEATURE REQ] Automatic brightness adjust based on content

[ArijitKHaldar]

Your project is pretty interesting..but I felt that something can be added to make it even better. Would you like to take a look at Lumen and see if we can get that behaviour in Clight?

I understand Clight primarily aims at adjusting brightness based on ambient light, but the framework is pretty light to work as a brightness controlling utility using keyboard shortcuts for window manager based workflows too. In that case, switching between web browser and a full screen terminal... specially on 14" laptops is a real pain at night.

[FedeDP]

Hi! Thanks for opening this feature request!
I think it can be surely done and it is a great idea!
I envision it like this:

• contentBased conf option under Backlight settings to enable this mode
• when it is enabled, Backlight module will capture ambient brightess like it normally does but won't set screen backlight
• instead, Screen module will compute current screen brightness (just like it does now), and will set screen backlight based on a mixture of current ambient brightness and screen brightness, with an algorithm that uses ambient brightness as a 'sliding window' and screen brightness to decide the correct point inside the sliding window.

For example:

• ambient brightness -> 0.75
• Sliding window -> 0.5 - 1.0
• screen brightness -> 0.2
• final backlight value -> 0.9 (ie: 1.0 - (0.2 * 0.5))

Moreover, Clight would expose new dbus API to let Screen module do a capture, so that one can manually trigger the behavior.
Thing is, lowering Screen timeout too much can have a huge impact on battery. Therefore i think that on battery the behavior should be mostly manual; instead when connected to AC, the behavior can be fully automated (with eg: a screen capture every 2s).
WDYT?

Again, thank you very much for your input!

[ArijitKHaldar]

Glad to be helpful in whatever small way possible...

That's a great idea for determining required brightness based on sliding window algorithm. Would love to try out your implementation of the idea.
Btw, may I request for some user-side control such as calling with manual flags when starting Clight for using on machines where camera might be an external one and used in a very different lighting condition (for example taking successive images of some objects for collecting data for ML training data creation).

What I mean to say is, Clight is already using the required modules for screen brightness control, so... personally, I prefer to use one program for a specific task on all my machines to make things simpler for me. Then, I can override any one of the functions manually in a simple script, if using on a machine that may not benefit from the ambient lighting, but will benefit from percentage of screen content that is white...or of brighter tones...or maybe the other way round (probably something like --no-camera or --no-screen-content)

So, it would be something like this:

• Default mode (what Clight presently is doing)
• Screen Content mode (your suggestion to my feature request)
• Manual mode
  • with all features off, Clight would be a simple brightness changing software based on user keyboard shortcuts)
  • with screen content (automatic brightness adjustment based on screen content)
  • with ambient light sensor/camera
  • screen content+light sensor/camera

And, I second your choice of manual behaviour on battery. Automated features would surely be helpful on Desktops, but may not be ideal for laptops (with weak or old battery)

[FedeDP]

Hi!
On PR #244 (feat_content_based branch) you can find the implementation of the new screen content feature, that is indeed a full reworking on the old screen backlight compensation tool.
You can try it out, if you don't mind! Any feedback is appreaciated ;)

Default mode (what Clight presently is doing)

Present!

Screen Content mode (your suggestion to my feature request)

Present!

with all features off, Clight would be a simple brightness changing software based on user keyboard shortcuts)

You can enable backlight.no_auto_calibration (https://github.com/FedeDP/Clight/blob/master/Extra/clight.conf#L89) for that!

with screen content (automatic brightness adjustment based on screen content)

This is not so useful IMHO, without knowing ambient brightness (ie: using it together with backlight captures)

with ambient light sensor/camera

Without auto calibration enabled and with screen-content based disabled -> you can have a keyboard shortcut to trigger the "Capture" action (same that you can find on Clight desktop file)

screen content+light sensor/camera

Same as above but with screen-content based enabled

To trigger Clight Capture, you can use Clight DBus API:
busctl --user call org.clight.clight /org/clight/clight org.clight.clight Capture "bb" false false

or use the provided desktop file!

[FedeDP]

Just wanted to let you know that the feature is now in master, if you are still looking forward to play with it :D

[ArijitKHaldar]

It's such an honor...being updated about this after so many months directly from you !! Thank you sir...I really appreciate it. Btw, I was using acpilight for the time being, since I was busy with my dissertation work. But now its done, so, I'll definitely check it out.

Actually things didn't work very well when I last tried it around March. I was having some issues integrating it with my XMonad WM. Had some high cpu usage issues for me. But, I'll try it again this time. 😄

[FedeDP]

Since this is a released feature (even if not perfect perhaps but pretty tweakable) I'll close this issue :)
Thank you!