wip: improvements to arranger view

src/devices/sequencer.rs

@@ -44,6 +44,87 @@ pub const KEYMAP_SEQUENCER: &'static [KeyBinding<App>] = keymap!(App {
     */
 });
 
+pub type PhraseData = Vec<Vec<MidiMessage>>;
+
+#[derive(Debug)]
+/// A MIDI sequence.
+pub struct Phrase {
+    pub name:   String,
+    pub length: usize,
+    pub notes:  PhraseData,
+    pub looped: Option<(usize, usize)>,
+    /// Immediate note-offs in view
+    pub percussive: bool
+}
+
+impl Default for Phrase {
+    fn default () -> Self {
+        Self::new("", 0, None)
+    }
+}
+
+impl Phrase {
+    pub fn new (name: &str, length: usize, notes: Option<PhraseData>) -> Self {
+        Self {
+            name:   name.to_string(),
+            length,
+            notes:  notes.unwrap_or(vec![Vec::with_capacity(16);length]),
+            looped: Some((0, length)),
+            percussive: true,
+        }
+    }
+    pub fn record_event (&mut self, pulse: usize, message: MidiMessage) {
+        if pulse >= self.length {
+            panic!("extend phrase first")
+        }
+        self.notes[pulse].push(message);
+    }
+    /// Check if a range `start..end` contains MIDI Note On `k`
+    pub fn contains_note_on (&self, k: u7, start: usize, end: usize) -> bool {
+        //panic!("{:?} {start} {end}", &self);
+        for events in self.notes[start.max(0)..end.min(self.notes.len())].iter() {
+            for event in events.iter() {
+                match event {
+                    MidiMessage::NoteOn {key,..} => {
+                        if *key == k {
+                            return true
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+        return false
+    }
+    /// Write a chunk of MIDI events to an output port.
+    pub fn process_out (
+        &self,
+        output:   &mut MIDIChunk,
+        notes_on: &mut [bool;128],
+        timebase: &Arc<Timebase>,
+        (frame0, frames, _): (usize, usize, f64),
+    ) {
+        let mut buf = Vec::with_capacity(8);
+        for (time, tick) in Ticks(timebase.pulse_per_frame()).between_frames(
+            frame0, frame0 + frames
+        ) {
+            let tick = tick % self.length;
+            for message in self.notes[tick].iter() {
+                buf.clear();
+                let channel = 0.into();
+                let message = *message;
+                LiveEvent::Midi { channel, message }.write(&mut buf).unwrap();
+                output[time as usize].push(buf.clone());
+                match message {
+                    MidiMessage::NoteOn  { key, .. } => notes_on[key.as_int() as usize] = true,
+                    MidiMessage::NoteOff { key, .. } => notes_on[key.as_int() as usize] = false,
+                    _ => {}
+                }
+            }
+        }
+    }
+}
+
 /// Phrase editor.
 pub struct Sequencer {
     pub mode:      bool,