cosmic-applets/applets/cosmic-applet-power-battery/src/backlight.rs

75 lines
2.1 KiB
Rust

// TODO: use udev to monitor for brightness changes?
// How should key bindings be handled? Need something like gnome-settings-daemon?
use std::{
fs::{self, File},
io::{self, Read},
path::PathBuf,
str::FromStr,
};
#[zbus::dbus_proxy(
default_service = "org.freedesktop.login1",
interface = "org.freedesktop.login1.Session"
)]
trait LogindSession {
fn set_brightness(&self, subsystem: &str, name: &str, brightness: u32) -> zbus::Result<()>;
}
struct Backlight(PathBuf);
impl Backlight {
fn brightness(&self) -> Option<u32> {
self.prop("brightness")
}
fn max_brightness(&self) -> Option<u32> {
self.prop("max_brightness")
}
async fn set_brightness(
&self,
session: &LogindSessionProxy<'_>,
value: u32,
) -> zbus::Result<()> {
session.set_brightness("backlight", "", value).await // XXX
}
fn prop<T: FromStr>(&self, name: &str) -> Option<T> {
let mut file = File::open(&self.0.join(name)).ok()?;
let mut s = String::new();
file.read_to_string(&mut s).ok()?;
s.parse().ok()
}
}
// Choose backlight with most "precision". This is what `light` does.
fn backlight() -> io::Result<Option<Backlight>> {
let mut best_backlight = None;
let mut best_max_brightness = 0;
for i in fs::read_dir("/sys/class/backlight")? {
let backlight = Backlight(i?.path());
if let Some(max_brightness) = backlight.max_brightness() {
if max_brightness > best_max_brightness {
best_backlight = Some(backlight);
best_max_brightness = max_brightness;
}
}
}
Ok(best_backlight)
}
// TODO: Cache device, max_brightness, etc.
async fn set_display_brightness(brightness: f64) -> io::Result<()> {
if let Some(backlight) = backlight()? {
if let Some(max_brightness) = backlight.max_brightness() {
let value = brightness.clamp(0., 1.) * (max_brightness as f64);
let value = value.round() as u32;
// XXX TODO
backlight.set_brightness(todo!(), value).await;
}
}
Ok(())
}
// TODO: keyboard backlight