tabula rasa

crates/timebase/src/lib.rs

@@ -0,0 +1,46 @@
+pub struct Timebase {
+    /// Sample rate
+    rate:        u64,
+    /// Current frame
+    frame:       u64,
+    /// Beats per bar
+    signature:   (u64, u64),
+    /// Beats per minute
+    bpm:         f64,
+}
+
+impl Timebase {
+    pub fn new (rate: u64, signature: (u64, u64), bpm: f64) -> Self {
+        Self {
+            rate,
+            frame: 0,
+            signature,
+            bpm,
+        }
+    }
+    pub fn seconds (&self) -> f64 {
+        self.frame as f64 / self.rate as f64
+    }
+    pub fn minutes (&self) -> f64 {
+        self.seconds / 60.0
+    }
+    pub fn beats (&self) -> f64 {
+        self.minutes / self.bpm
+    }
+    pub fn bar (&self) -> u64 {
+        ((self.beats() * self.signature.0 as f64) / self.signature.1 as f64) as u64
+    }
+    pub fn beat (&self) -> u64 {
+        ((self.beats() * self.signature.0 as f64) % self.signature.1 as f64) as u64
+    }
+    pub fn time_string (&self) -> String {
+        let minutes = self.minutes() as u64;
+        let seconds = self.seconds() as u64;
+        let milliseconds = self.seconds() - seconds;
+        format!("{minutes}:{seconds}.{milliseconds:03}")
+    }
+    pub fn beat_string (&self) -> String {
+        let beats = self.beats() as u64;
+        format!("{beats} {}/{}", minutes, self.beat(), self.signature.1)
+    }
+}