Easiest way to force a refresh every x milliseconds

[AyashiNoCeres]

Current the window only updates when it needs to, which is great but what about being able to override this?

What's the simplest way to do this? Say I want to force the screen to refresh every x milliseconds

[emilk]

There is no simple way to do this in eframe at the moment. What you can do is clone the RepaintSignal and send it to a background thread which just calls it every x milliseconds. Not great, not terrible.

[AyashiNoCeres]

thanks i'll give this a try!

[follower]

It wasn't clear to me if you specifically wanted a refresh/repaint that was not every frame--but if "a refresh/repaint every frame " is okay then you can use request_repaint() in your update() method, as used in some of the demos, e.g.:

egui/egui_demo_lib/src/apps/demo/multi_touch.rs

Lines 136 to 137 in 0b52813

	// we want continuous UI updates, so the circle can smoothly follow the arrow's origin:
	ui.ctx().request_repaint();

and

egui/egui_demo_lib/src/wrap_app.rs

Lines 158 to 247 in b155996

	/// How often we repaint the demo app by default
	#[derive(Clone, Copy, Debug, Eq, PartialEq)]
	enum RunMode {
	/// This is the default for the demo.
	///
	/// If this is selected, egui is only updated if are input events
	/// (like mouse movements) or there are some animations in the GUI.
	///
	/// Reactive mode saves CPU.
	///
	/// The downside is that the UI can become out-of-date if something it is supposed to monitor changes.
	/// For instance, a GUI for a thermostat need to repaint each time the temperature changes.
	/// To ensure the UI is up to date you need to call `egui::Context::request_repaint()` each
	/// time such an event happens. You can also chose to call `request_repaint()` once every second
	/// or after every single frame - this is called `Continuous` mode,
	/// and for games and interactive tools that need repainting every frame anyway, this should be the default.
	Reactive,
	/// This will call `egui::Context::request_repaint()` at the end of each frame
	/// to request the backend to repaint as soon as possible.
	///
	/// On most platforms this will mean that egui will run at the display refresh rate of e.g. 60 Hz.
	///
	/// For this demo it is not any reason to do so except to
	/// demonstrate how quickly egui runs.
	///
	/// For games or other interactive apps, this is probably what you want to do.
	/// It will guarantee that egui is always up-to-date.
	Continuous,
	}
	/// Default for demo is Reactive since
	/// 1) We want to use minimal CPU
	/// 2) There are no external events that could invalidate the UI
	/// so there are no events to miss.
	impl Default for RunMode {
	fn default() -> Self {
	RunMode::Reactive
	}
	}
	// ----------------------------------------------------------------------------
	#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
	#[cfg_attr(feature = "persistence", serde(default))]
	struct BackendPanel {
	open: bool,
	#[cfg_attr(feature = "persistence", serde(skip))]
	// go back to `Reactive` mode each time we start
	run_mode: RunMode,
	/// current slider value for current gui scale
	pixels_per_point: Option<f32>,
	/// maximum size of the web browser canvas
	max_size_points_ui: egui::Vec2,
	max_size_points_active: egui::Vec2,
	#[cfg_attr(feature = "persistence", serde(skip))]
	frame_history: crate::frame_history::FrameHistory,
	#[cfg_attr(feature = "persistence", serde(skip))]
	output_event_history: std::collections::VecDeque<egui::output::OutputEvent>,
	}
	impl Default for BackendPanel {
	fn default() -> Self {
	Self {
	open: false,
	run_mode: Default::default(),
	pixels_per_point: Default::default(),
	max_size_points_ui: egui::Vec2::new(1024.0, 2048.0),
	max_size_points_active: egui::Vec2::new(1024.0, 2048.0),
	frame_history: Default::default(),
	output_event_history: Default::default(),
	}
	}
	}
	impl BackendPanel {
	fn update(&mut self, ctx: &egui::CtxRef, frame: &mut epi::Frame<'_>) {
	self.frame_history
	.on_new_frame(ctx.input().time, frame.info().cpu_usage);
	if self.run_mode == RunMode::Continuous {
	// Tell the backend to repaint as soon as possible
	ctx.request_repaint();
	}
	}

But if a refresh every frame is too frequent then you'd want to use the approach @emilk suggested.

Some docs here: https://docs.rs/egui/0.11.0/egui/struct.Context.html#method.request_repaint

[AyashiNoCeres]

Refreshing every frame is fine. so yeah that works pretty well for me! Thank you!

[nalply]

Sorry to ask, but what's the use case for repainting every frame? If the update doesn't work like you expect perhaps it's better to report this as a bug?

I respectfully ask this so you don't try to solve an XY problem.