Add non-blocking update function

CHANGELOG.md

@@ -10,6 +10,10 @@
 
 - **(breaking)** [#71](https://github.com/embedded-graphics/simulator/pull/71) Added support for non-square pixels.
 
+### Changed
+
+- [#72](https://github.com/embedded-graphics/simulator/pull/72) `set_max_fps` now accepts `0` to disable the FPS limiter.
+
 ### Fixed
 
 - [#71](https://github.com/embedded-graphics/simulator/pull/71) Fixed pixel spacing for unscaled outputs.

src/window/mod.rs

@@ -2,6 +2,7 @@ use std::{
     env,
     fs::File,
     io::BufReader,
+    num::NonZeroU32,
     ops::Deref,
     process, thread,
     time::{Duration, Instant},
@@ -26,25 +27,29 @@ mod multi_window;
 pub use multi_window::MultiWindow;
 
 pub(crate) struct FpsLimiter {
-    max_fps: u32,
+    max_fps: Option<NonZeroU32>,
     frame_start: Instant,
 }
 
 impl FpsLimiter {
     pub(crate) fn new() -> Self {
         Self {
-            max_fps: 60,
+            max_fps: NonZeroU32::new(60),
             frame_start: Instant::now(),
         }
     }
 
-    fn desired_loop_duration(&self) -> Duration {
-        Duration::from_secs_f32(1.0 / self.max_fps as f32)
+    fn desired_loop_duration(&self) -> Option<Duration> {
+        Some(Duration::from_secs_f32(1.0 / self.max_fps?.get() as f32))
     }
 
     fn sleep(&mut self) {
-        let sleep_duration = (self.frame_start + self.desired_loop_duration())
-            .saturating_duration_since(Instant::now());
+        let Some(duration) = self.desired_loop_duration() else {
+            return;
+        };
+
+        let sleep_duration =
+            (self.frame_start + duration).saturating_duration_since(Instant::now());
         thread::sleep(sleep_duration);
 
         self.frame_start = Instant::now();
@@ -202,8 +207,8 @@ impl Window {
             .events(&self.output_settings)
     }
 
-    /// Sets the FPS limit of the window.
+    /// Changes the FPS limit of the window. Set to `0` to disable the FPS limiter.
     pub fn set_max_fps(&mut self, max_fps: u32) {
-        self.fps_limiter.max_fps = max_fps;
+        self.fps_limiter.max_fps = NonZeroU32::new(max_fps);
     }
 }

src/window/multi_window.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use std::{collections::HashMap, num::NonZeroU32};
 
 use embedded_graphics::{pixelcolor::Rgb888, prelude::*};
 
@@ -125,9 +125,9 @@ impl MultiWindow {
         display.bounding_box().contains(p).then_some(p)
     }
 
-    /// Sets the FPS limit of the window.
+    /// Changes the FPS limit of the window. Set to `0` to disable the FPS limiter.
     pub fn set_max_fps(&mut self, max_fps: u32) {
-        self.fps_limiter.max_fps = max_fps;
+        self.fps_limiter.max_fps = NonZeroU32::new(max_fps);
     }
 }