tek/crates/tek_timer/src/transport.rs

use crate::*;

/// Stores and displays time-related state.
pub struct TransportToolbar {
    /// Enable metronome?
    pub metronome: bool,
    pub focused:   bool,
    pub entered:   bool,
    pub selected:  TransportFocus,
    /// Current sample rate, tempo, and PPQ.
    pub timebase:  Arc<Timebase>,
    /// JACK client handle (needs to not be dropped for standalone mode to work).
    pub jack:      Option<JackClient>,
    /// JACK transport handle.
    pub transport: Option<Transport>,
    /// Quantization factor
    pub quant:     usize,
    /// Global sync quant
    pub sync:      usize,
    /// Current transport state
    pub playing:   Option<TransportState>,
    /// Current position according to transport
    pub playhead:  usize,
    /// Global frame and usec at which playback started
    pub started:   Option<(usize, usize)>,
}

process!(TransportToolbar |self, _client, scope| {
    self.update(&scope);
    Control::Continue
});

impl TransportToolbar {

    pub fn standalone () -> Usually<Arc<RwLock<Self>>> {
        let mut transport = Self::new(None);
        transport.focused = true;
        transport.entered = true;
        let jack = JackClient::Inactive(
            Client::new("tek_transport", ClientOptions::NO_START_SERVER)?.0
        );
        transport.transport = Some(jack.transport());
        let transport = Arc::new(RwLock::new(transport));
        transport.write().unwrap().jack = Some(
            jack.activate(
                &transport.clone(),
                |state, client, scope| {
                    state.write().unwrap().process(client, scope)
                }
            )?
        );
        Ok(transport)
    }

    pub fn new (transport: Option<Transport>) -> Self {
        let timebase = Arc::new(Timebase::default());
        Self {
            selected:  TransportFocus::BPM,
            metronome: false,
            focused:   false,
            entered:   false,
            playhead:  0,
            playing:   Some(TransportState::Stopped),
            started:   None,
            quant:     24,
            sync:      timebase.ppq() as usize * 4,
            jack:      None,
            transport,
            timebase,
        }
    }

    pub fn toggle_play (&mut self) -> Usually<()> {
        let transport = self.transport.as_ref().unwrap();
        self.playing = match self.playing.expect("1st frame has not been processed yet") {
            TransportState::Stopped => {
                transport.start()?;
                Some(TransportState::Starting)
            },
            _ => {
                transport.stop()?;
                transport.locate(0)?;
                Some(TransportState::Stopped)
            },
        };
        Ok(())
    }

    pub fn update (&mut self, scope: &ProcessScope) -> (bool, usize, usize, usize, usize, f64) {
        let CycleTimes {
            current_frames,
            current_usecs,
            next_usecs,
            period_usecs
        } = scope.cycle_times().unwrap();
        let chunk_size = scope.n_frames() as usize;
        let transport = self.transport.as_ref().unwrap().query().unwrap();
        self.playhead = transport.pos.frame() as usize;
        let mut reset = false;
        if self.playing != Some(transport.state) {
            match transport.state {
                TransportState::Rolling => {
                    self.started = Some((
                        current_frames as usize,
                        current_usecs  as usize,
                    ));
                },
                TransportState::Stopped => {
                    self.started = None;
                    reset = true;
                },
                _ => {}
            }
        }
        self.playing = Some(transport.state);
        (
            reset,
            current_frames as usize,
            chunk_size as usize,
            current_usecs as usize,
            next_usecs as usize,
            period_usecs as f64
        )
    }

    pub fn bpm (&self) -> usize {
        self.timebase.bpm() as usize
    }

    pub fn ppq (&self) -> usize {
        self.timebase.ppq() as usize
    }

    pub fn pulse (&self) -> usize {
        self.timebase.frame_to_pulse(self.playhead as f64) as usize
    }

    pub fn usecs (&self) -> usize {
        self.timebase.frame_to_usec(self.playhead as f64) as usize
    }

}