Use better rounded divisions (#177)

* Use better rounded divisions

* Rename div_round to div_round_u32

Author: gtarsia

src/brightness_backend/brightnessctl.rs

@@ -1,3 +1,5 @@
+use crate::global_utils::div_round_u32;
+
 use super::{BrightnessBackend, BrightnessBackendConstructor};
 
 const EXPECT_STR: &str = "VirtualDevice didn't test the command during initialization";
@@ -111,10 +113,16 @@ impl VirtualDevice {
 
 	fn set_percent(&mut self, mut val: u32) -> anyhow::Result<()> {
 		val = val.clamp(0, 100);
-		self.current = self.max.map(|max| val * max / 100);
+		self.current = self.max.map(|max| div_round_u32(val * max, 100));
 		let _: String = self.run(("set", &*format!("{val}%")))?;
 		Ok(())
 	}
+
+	pub fn get_percent(&mut self) -> u32 {
+		let curr = self.get_current();
+		let max = self.get_max();
+		div_round_u32(curr * 100, max)
+	}
 }
 
 impl BrightnessBackendConstructor for BrightnessCtl {
@@ -135,20 +143,12 @@ impl BrightnessBackend for BrightnessCtl {
 	}
 
 	fn lower(&mut self, by: u32) -> anyhow::Result<()> {
-		let curr = self.get_current();
-		let max = self.get_max();
-
-		let curr = curr * 100 / max;
-
+		let curr = self.device.get_percent();
 		self.device.set_percent(curr.saturating_sub(by))
 	}
 
 	fn raise(&mut self, by: u32) -> anyhow::Result<()> {
-		let curr = self.get_current();
-		let max = self.get_max();
-
-		let curr = curr * 100 / max;
-
+		let curr = self.device.get_percent();
 		self.device.set_percent(curr + by)
 	}
 

src/global_utils.rs

@@ -262,3 +262,7 @@ fn volume_parser(is_sink: bool, value: &str) -> Result<(ArgTypes, Option<String>
 	}
 	Ok(v)
 }
+
+pub fn div_round_u32(a: u32, b: u32) -> u32 {
+	(a + b / 2) / b
+}

src/server/osd_window.rs

@@ -153,7 +153,7 @@ impl SwayosdWindow {
 		let max = brightness_backend.get_max() as f64;
 		let progress = self.build_progress_widget(brightness / max);
 		let label = self.build_text_widget(
-			Some(&format!("{}%", (brightness / max * 100.) as i32)),
+			Some(&format!("{}%", (brightness / max * 100.).round() as i32)),
 			Some(4),
 		);