kira

evil light

kira is a script, that disguises itself as an rust application, that can set the brightness of your monitor of your Linux laptop.

The distinguishing feature of kira, the reason I wrote it instead of using alternatives like light or acpilight, which are better in every other respect, is the smooth setting of the brightness.

Brightness is set step-wise over time resulting in a linear and smooth transition of brightness.

Usage

$ kira            # set brightness to 100%
$ kira 33         # set brightness to 33%
$ kira +12        # increase brightness by 10%
$ kira -43        # decrease brightness by 43%

Limitations

• Works only on specific machines and OSes
  • Linux (sysfs)
  • Intel graphics card
• No meaningful error handling
• Interpolation is linear only

How it works

kira writes to the sysfs kernel API of Linux. Specifically, /sys/class/backlight/intel_backlight.

The transition is achieved by looping from the current value until the target value and sleeping the thread for a couple of nanoseconds on each step. This means the transition speed (smoothness) is dependent on the range of values of my specific device and magic amount of nanoseconds I chose.

This happens to work out on my Thinkpad x230, but is unlikely to work universally.

Working together

If for some bizarre reason you have to urge to collaborate in this project, shoot me a mail or open an issue to start discussing ideas.