Trait PluginLogic 

pub trait PluginLogic: Send + 'static {
    // Required methods
    fn reset(&mut self, sample_rate: f64, max_block_size: usize);
    fn process(
        &mut self,
        buffer: &mut AudioBuffer<'_, f32>,
        events: &EventList,
        context: &mut ProcessContext<'_>,
    ) -> ProcessStatus;

    // Provided methods
    fn supports_in_place() -> bool
       where Self: Sized { ... }
    fn bus_layouts() -> Vec<BusLayout>
       where Self: Sized { ... }
    fn save_state(&self) -> Vec<u8>  { ... }
    fn load_state(&mut self, _data: &[u8]) -> Result<(), StateLoadError> { ... }
    fn state_changed(&mut self) { ... }
    fn latency(&self) -> u32 { ... }
    fn tail(&self) -> u32 { ... }
    fn layout(&self) -> GridLayout { ... }
    fn render(&self, _backend: &mut dyn RenderBackend) { ... }
    fn uses_custom_render(&self) -> bool { ... }
    fn hit_test(
        &self,
        widgets: &[WidgetRegion],
        x: f32,
        y: f32,
    ) -> Option<usize> { ... }
    fn custom_editor(&self) -> Option<Box<dyn Editor>> { ... }
}

The f32-buffer user-facing plugin trait.

Plugin authors implement this in a single impl block when their audio path is f32 end-to-end (the default - matches the host wire format for nearly all DAWs and formats). truce::prelude and truce::prelude32 re-export this name directly; truce::prelude64m does too (the m mixed-precision prelude keeps the audio buffer at f32 and only switches the param.read() precision).

Only Self::reset and Self::process are required; everything else has a default. Headless (no-GUI) plugins leave layout / render / custom_editor at their defaults - the format wrappers fall back to a minimal built-in editor.

Required Methods

fn reset(&mut self, sample_rate: f64, max_block_size: usize)

Reset for a new sample rate / block size. Called before the first process and any time the host reconfigures.

fn process( &mut self, buffer: &mut AudioBuffer<'_, f32>, events: &EventList, context: &mut ProcessContext<'_>, ) -> ProcessStatus

Process one block of audio. Real-time - no allocations, locks, or I/O.

Provided Methods

fn supports_in_place() -> bool

where Self: Sized,

Opt into zero-copy in-place I/O. When this returns true, the format wrapper skips its safety memcpy on host-aliased buffers and hands the plugin the raw shared memory through AudioBuffer::in_out_mut(ch). The plugin must check AudioBuffer::is_in_place(ch) per channel before reading input(ch).

Default false: the wrapper copies aliased inputs into scratch so input(ch) and output(ch) are always disjoint. Costs one memcpy per aliased channel per block.

fn bus_layouts() -> Vec<BusLayout>

where Self: Sized,

Supported audio bus configurations. The host picks one; the others are rejected at bus-config time before process is ever called. Default: stereo in, stereo out.

fn save_state(&self) -> Vec<u8>

Serialize plugin-specific state (DSP state, not params - those are saved automatically). Default: no extra state.

fn load_state(&mut self, _data: &[u8]) -> Result<(), StateLoadError>

Restore plugin-specific state.

Errors

Return Err(StateLoadError) when the blob is malformed or otherwise can’t be interpreted - the format wrapper logs the failure (and on hosts that support it, surfaces it to the DAW).

fn state_changed(&mut self)

Called on the audio thread immediately after Self::load_state returns. Invalidate or recompute any caches the next process() reads. Default: no-op.

fn latency(&self) -> u32

Report latency in samples for plugin delay compensation.

fn tail(&self) -> u32

Report tail time in samples (audio produced after input stops - reverbs, delays). u32::MAX for infinite tail.

fn layout(&self) -> GridLayout

Return the widget layout for the built-in GUI. Default: empty layout. Plugins that supply a custom editor via Self::custom_editor can leave this default.

fn render(&self, _backend: &mut dyn RenderBackend)

Render the GUI into a backend. Default: no-op. Override only for custom GPU/CPU rasterisation outside the standard widget set; flip Self::uses_custom_render to true when you do.

fn uses_custom_render(&self) -> bool

Whether this plugin overrides Self::render. The shell uses the standard widget drawing from Self::layout when this is false. Default: false.

fn hit_test(&self, widgets: &[WidgetRegion], x: f32, y: f32) -> Option<usize>

Hit test: which widget (if any) is at (x, y)? Default: circular for knobs, rectangular for everything else, meters skipped.

fn custom_editor(&self) -> Option<Box<dyn Editor>>

Provide a custom Editor instead of the built-in widget layout (egui, iced, slint, raw window handle). The shell calls this first; if it returns None, falls back to the built-in editor from Self::layout.

Implementors