Merge pull request #5 from Fredemus/feature/more-formatters

a few more formatters

src/formatters.rs

@@ -6,7 +6,6 @@ use std::sync::Arc;
 pub fn f32_rounded(digits: usize) -> Arc<dyn Fn(f32) -> String + Send + Sync> {
     Arc::new(move |x| format!("{:.digits$}", x))
 }
-
 /// Format a `[0, 1]` number as a percentage. Does not include the percent sign, you should specify
 /// this as the parameter's unit.
 pub fn f32_percentage(digits: usize) -> Arc<dyn Fn(f32) -> String + Send + Sync> {
@@ -25,6 +24,69 @@ pub fn from_f32_percentage() -> Arc<dyn Fn(&str) -> Option<f32> + Send + Sync> {
     })
 }
 
+/// Turn an `f32` value from linear to dBFS (reference value 1)
+pub fn f32_lin_to_db(digits: usize) -> Arc<dyn Fn(f32) -> String + Send + Sync> {
+    Arc::new(move |x| format!("{:.digits$}", x.log10() * 20.0))
+}
+/// Parse a `dBFS` value to a linear value. Handles the dB unit for you. Used in
+/// conjunction with [`f32_lin_to_db`].
+pub fn from_f32_lin_to_db() -> Arc<dyn Fn(&str) -> Option<f32> + Send + Sync> {
+    Arc::new(|string| {
+        string
+            .trim_end_matches(&[' ', 'd', 'B'])
+            .parse()
+            .ok()
+            .map(|x: f32| 10f32.powf(x / 20.0))
+    })
+}
+/// Turn an `f32` value `[-1, 1]` to a panning value `[100L, 100R]` Value of `0.0` becomes `"C"`
+pub fn f32_panning() -> Arc<dyn Fn(f32) -> String + Send + Sync> {
+    Arc::new(move |x| {
+        if x == 0. {
+            "C".to_string()
+        } else if x > 0. {
+            format!("{:.0}R", x * 100.)
+        } else {
+            format!("{:.0}L", x * -100.)
+        }
+    })
+}
+/// Parse a pan value to a linear value, range `[-1, 1]`. Used in
+/// conjunction with [`f32_panning`].
+pub fn from_f32_panning() -> Arc<dyn Fn(&str) -> Option<f32> + Send + Sync> {
+    Arc::new(|string| {
+        if string.contains('L') {
+            string
+                .trim_end_matches(&[' ', 'L'])
+                .parse()
+                .ok()
+                .map(|x: f32| x / -100.)
+        } else if string.contains('R') {
+            string
+                .trim_end_matches(&[' ', 'R'])
+                .parse()
+                .ok()
+                .map(|x: f32| x / 100.)
+        } else if string == "C" {
+            Some(0.)
+        } else {
+            string.trim_end_matches(&[' ']).parse().ok().map(|x: f32| x)
+        }
+    })
+}
+
+/// Round an `f32` value and divide it by 1000 when it gets over 1000
+pub fn f32_hz_then_khz(digits: usize) -> Arc<dyn Fn(f32) -> String + Send + Sync> {
+    Arc::new(move |x| {
+        if x < 1000.0 {
+            format!("{:.digits$}", x)
+        } else {
+            let digits = digits + 1;
+            format!("{:.digits$}", x / 1000.0)
+        }
+    })
+}
+
 /// Format an order/power of two. Useful in conjunction with [`from_power_of_two()`] to limit
 /// integer parameter ranges to be only powers of two.
 pub fn i32_power_of_two() -> Arc<dyn Fn(i32) -> String + Send + Sync> {
@@ -36,3 +98,33 @@ pub fn i32_power_of_two() -> Arc<dyn Fn(i32) -> String + Send + Sync> {
 pub fn from_i32_power_of_two() -> Arc<dyn Fn(&str) -> Option<i32> + Send + Sync> {
     Arc::new(|string| string.parse().ok().map(|n: i32| (n as f32).log2() as i32))
 }
+
+const NOTES: [&str; 12] = [
+    "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B",
+];
+/// Turns an integer midi number (range 0-127 usually) into a note name, e.g. 69 -> A4
+pub fn i32_note_formatter() -> Arc<dyn Fn(i32) -> String + Send + Sync> {
+    Arc::new(move |x| {
+        let note = x as usize;
+        let note_name = NOTES[note % 12].to_string();
+        let octave = (note / 12) as i32 - 1;
+        format!("{note_name}{octave}")
+    })
+}
+/// parses a note name into a midi number (range 0-127 usually), e.g. A#4 -> 70
+pub fn from_i32_note_formatter() -> Arc<dyn Fn(&str) -> Option<i32> + Send + Sync> {
+    Arc::new(|string| {
+        // string is too short to be a note name
+        if string.len() < 2 {
+            return None;
+        }
+        let (note_name, octave) = if string.contains("#") {
+            string.split_at(2)
+        } else {
+            string.split_at(1)
+        };
+        // using unwrap_or here, or else trying to parse "##" breaks it
+        let note = NOTES.iter().position(|&r| r == note_name).unwrap_or(0) as i32;
+        octave.parse().ok().map(|n: i32| (n + 1) * 12 + note)
+    })
+}