Struct PaintPacer 

pub struct PaintPacer { /* private fields */ }

Shared, mutable editor scale factor.

Single source of truth for the live content-scale of an open plugin window. Each GUI backend (egui / iced / slint) constructs one in Editor::open, stores it on the editor for set_scale_factor to write through, and hands a clone to its baseview WindowHandler so the render thread can pick up changes between frames.

Two writers, one reader-per-frame:

• Editor::set_scale_factor (host → editor, e.g. CLAP set_scale, VST3 Windows IPlugViewContentScaleSupport).
• WindowEvent::Resized (baseview → handler, fired when the OS reports a new content scale, e.g. dragging the window across monitors with different DPIs).

Most-recent-write wins. The handler tracks a last_applied_scale alongside its EditorScale clone and, when it observes a divergence at frame start, recomputes physical sizes and reconfigures its surface / renderer. Paces editor paints to the compositor’s measured consumption rate.

A child-window swapchain acquire (get_current_texture) blocks until the compositor frees a frame slot, and a host may compose an embedded editor window far below the editor’s tick rate (REAPER on Windows composes FX child windows at ~13 Hz). Painting every tick then parks the host’s GUI thread in that wait - measured at 74 ms of every 77 ms frame, which saturates the host’s whole UI and reads as the DAW hanging. Editors feed each paint’s measured acquire wait into Self::record_acquire and skip the tick while Self::should_hold is true, converging on the rate the compositor actually displays (which is all the user ever saw).

The pace is a decayed maximum: a successfully paced paint measures a ~0 ms acquire, so pacing by the last wait alone oscillates (paced, unpaced, paced, …). Holding the estimate through the zeros and shrinking it ~15% per paint lets it track a compositor that genuinely speeds up within roughly a second.

Implementations

impl PaintPacer

pub fn should_hold(&self) -> bool

Whether this tick’s paint should be skipped: the previous acquire showed the compositor hasn’t caught up yet.

pub fn record_acquire(&mut self, wait: Duration)

Record how long a paint’s swapchain acquire blocked, scheduling the earliest next paint accordingly.

Trait Implementations

impl Debug for PaintPacer

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for PaintPacer

fn default() -> PaintPacer

Returns the “default value” for a type.