linear dimming

src/display.rs

@@ -97,8 +97,8 @@ impl Brightness {
         self.0
     }
 
-    pub fn dimm(self, scale: u8) -> Brightness {
-        Brightness(self.0 >> scale)
+    pub fn dimm(self, dimming: u8) -> Brightness {
+        Brightness(self.0.saturating_sub(dimming))
     }
 
     // Scales brightness (0-255) to range between IO_SEGMENT_ON_MIN_US and IO_SEGMENT_ON_MAX_US

src/main.rs

@@ -53,7 +53,8 @@ pub const IO_SEGMENT_ON_MAX_US: u32 = 700; // How long in μs to hold segment LE
 // Dimming
 pub const DISPLAY_FPS: u16 = (1_000_000 / (IO_SEGMENT_RATE_US * DISPLAY_SEGMENTS as u32)) as u16;
 pub const DISPLAY_DIMM_FRAMES: u16 = DISPLAY_FPS * 10; // How many frames of inactivity before dimming
-pub const DISPLAY_DIMM_SCALE: u8 = 4; // Number of bit shifts of brighness to dim
+pub const DISPLAY_DIMM_SPEED: u8 = 4; // Dimm by amount every frame when sleeping
+pub const DISPLAY_UNDIMM_SPEED: u8 = 16; // Brighten by amount every frame when not sleeping
 
 // Calculator setup
 pub const STACK_DEPTH: usize = 7;
@@ -121,6 +122,7 @@ pub struct IOLoop {
     readount: Option<KeyReadout>,
     debounce: Debounce,
     sleep_timer: u16,
+    dimming: u8,
 }
 
 impl IOLoop {
@@ -135,6 +137,7 @@ impl IOLoop {
             readount: None,
             debounce: Default::default(),
             sleep_timer: 0,
+            dimming: u8::MAX,
         }
     }
 
@@ -168,6 +171,12 @@ impl IOLoop {
                 self.sleep_timer = self.sleep_timer.saturating_add(1);
             }
 
+            if self.is_sleep() {
+                self.dimming = self.dimming.saturating_add(DISPLAY_DIMM_SPEED);
+            } else {
+                self.dimming = self.dimming.saturating_sub(DISPLAY_UNDIMM_SPEED);
+            }
+
             key
         } else {
             None
@@ -178,16 +187,16 @@ impl IOLoop {
         self.sleep_timer >= DISPLAY_DIMM_FRAMES
     }
 
+    pub fn dimming(&self) -> u8 {
+        self.dimming
+    }
+
     pub fn display_on(&mut self) -> Brightness {
         self.select_off();
         let segment = self.dispaly[self.index];
         let brighness = segment.apply(&mut self.segment_pins);
         self.select_on();
-        if self.is_sleep() {
-            brighness.dimm(DISPLAY_DIMM_SCALE)
-        } else {
-            brighness
-        }
+        brighness.dimm(self.dimming)
     }
 
     pub fn display_off(&mut self) {