Added adaptive brightness functionality

Un-hard-code the lookup table & minor fixes

Minor fix: clamp the brightness value down so that it does not exceed max

Author: isoamyl50

src/backlight.rs

@@ -10,9 +10,11 @@ use input::event::{
 };
 use crate::TIMEOUT_MS;
 
+const MAX_DISPLAY_BRIGHTNESS: u32 = 509;
+const MAX_TOUCH_BAR_BRIGHTNESS: u32 = 255;
+const LOOKUP_TABLE_SIZE: usize = MAX_DISPLAY_BRIGHTNESS as usize + 1;
 const BRIGHTNESS_DIM_TIMEOUT: i32 = TIMEOUT_MS * 3; // should be a multiple of TIMEOUT_MS
 const BRIGHTNESS_OFF_TIMEOUT: i32 = TIMEOUT_MS * 6; // should be a multiple of TIMEOUT_MS
-const DEFAULT_BRIGHTNESS: u32 = 128;
 const DIMMED_BRIGHTNESS: u32 = 1;
 
 fn read_attr(path: &Path, attr: &str) -> u32 {
@@ -30,7 +32,17 @@ fn find_backlight() -> Result<PathBuf> {
             return Ok(entry.path());
         }
     }
-    Err(anyhow!("No backlight device found"))
+    Err(anyhow!("No Touch Bar backlight device found"))
+}
+
+fn find_display_backlight() -> Result<PathBuf> {
+    for entry in fs::read_dir("/sys/class/backlight/")? {
+        let entry = entry?;
+        if entry.file_name().to_string_lossy().eq("apple-panel-bl") {
+            return Ok(entry.path());
+        }
+    }
+    Err(anyhow!("No Built-in Retina Display backlight device found"))
 }
 
 fn set_backlight(mut file: &File, value: u32) {
@@ -41,20 +53,29 @@ pub struct BacklightManager {
     last_active: Instant,
     current_bl: u32,
     lid_state: SwitchState,
-    bl_file: File
+    bl_file: File,
+    display_bl_path: PathBuf
 }
 
 impl BacklightManager {
     pub fn new() -> BacklightManager {
         let bl_path = find_backlight().unwrap();
+        let display_bl_path = find_display_backlight().unwrap();
         let bl_file = OpenOptions::new().write(true).open(bl_path.join("brightness")).unwrap();
         BacklightManager {
             bl_file,
             lid_state: SwitchState::Off,
             current_bl: read_attr(&bl_path, "brightness"),
-            last_active: Instant::now()
+            last_active: Instant::now(),
+            display_bl_path
         }
     }
+    fn display_to_touchbar(display: u32) -> u32 {
+        let normalized = display as f64 / MAX_DISPLAY_BRIGHTNESS as f64;
+        // Add one so that the touch bar does not turn off
+        let adjusted = (normalized.powf(0.5) * MAX_TOUCH_BAR_BRIGHTNESS as f64) as u32 + 1;
+        adjusted.min(MAX_TOUCH_BAR_BRIGHTNESS) // Clamp the value to the maximum allowed brightness
+    }
     pub fn process_event(&mut self, event: &Event) {
         match event {
             Event::Keyboard(_) | Event::Pointer(_) | Event::Gesture(_) | Event::Touch(_) => {
@@ -80,7 +101,7 @@ impl BacklightManager {
         let new_bl = if self.lid_state == SwitchState::On {
             0
         } else if since_last_active < BRIGHTNESS_DIM_TIMEOUT as u64 {
-            DEFAULT_BRIGHTNESS
+            BacklightManager::display_to_touchbar(read_attr(&self.display_bl_path, "brightness"))
         } else if since_last_active < BRIGHTNESS_OFF_TIMEOUT as u64 {
             DIMMED_BRIGHTNESS
         } else {

src/config.rs

@@ -124,4 +124,4 @@ impl ConfigManager {
     pub fn pollfd(&self) -> PollFd {
         PollFd::new(&self.inotify_fd, PollFlags::POLLIN)
     }
-}
+}