add brightness service and slider

services/brightness/__init__.py

@@ -0,0 +1,52 @@
+from astal import read_file, write_file, gi
+
+gi.require_version("GObject", "2.0")
+gi.require_version("GUdev", "1.0")
+from gi.repository import GObject, GUdev, GLib
+
+class Brightness(GObject.Object):
+    _brightness: float = 0 
+
+    def __init__(self, device: str):
+        super().__init__()
+
+        self._device_name = device
+        self._udev_client = GUdev.Client.new(["backlight"])
+        self._udev_client.connect('uevent', self.on_uevent)
+
+    def on_uevent(self, client, action, device):
+        if device.get_name() != self._device_name:
+            return
+
+        self._brightness = self._get_brightness()
+        self.notify('brightness')
+
+    def _get_brightness(self):
+        return self._get_current_brightness() / self._get_max_brightness()
+
+    def _get_current_brightness(self):
+        return int(read_file(f"/sys/class/backlight/{self._device_name}/brightness"))
+
+    def _get_max_brightness(self):
+        return int(read_file(f"/sys/class/backlight/{self._device_name}/max_brightness"))
+
+    @GObject.Property(type=float)
+    def brightness(self):
+        return self._brightness
+
+    @brightness.setter
+    def brightness(self, value: float):
+        if value < 0:
+            value = 0
+
+        elif value > 1:
+            value = 1
+
+        self._brightness = value
+        GLib.file_set_contents_full(f"/sys/class/backlight/{self._device_name}/brightness", bytes(str(round(self._brightness * self._get_max_brightness())), 'utf-8'), GLib.FileSetContentsFlags.ONLY_EXISTING, 0o666)
+
+    def get_brightness(self):
+        return self._brightness
+
+    def set_brightness(self, value):
+        self.brightness = value