Improve Simulator CPU Usage up to 50%. (#45)

* only create texture at start of program

* limit window draw loop to 60Hz

* allow user to set max fps

CHANGELOG.md

@@ -6,6 +6,14 @@
 
 ## [Unreleased] - ReleaseDate
 
+### Added
+
+- [#45](https://github.com/embedded-graphics/simulator/pull/45) Added `OutputSettingsBuilder::max_fps` to set the maximum FPS of the simulator.
+
+### Changed
+
+- [#45](https://github.com/embedded-graphics/simulator/pull/45) Limit simulator to 60FPS by default.
+
 ## [0.4.0] - 2022-09-19
 
 ### Changed

Cargo.toml

@@ -24,8 +24,9 @@ image = "0.23.14"
 base64 = "0.13.0"
 embedded-graphics = "0.7.1"
 sdl2 = { version = "0.35.1", optional = true }
+ouroboros = { version = "0.15.5", optional = true }
 
 [features]
-default = [ "with-sdl" ]
-fixed_point = [ "embedded-graphics/fixed_point" ]
-with-sdl = [ "sdl2" ]
+default = ["with-sdl"]
+fixed_point = ["embedded-graphics/fixed_point"]
+with-sdl = ["sdl2", "ouroboros"]

src/output_settings.rs

@@ -10,6 +10,8 @@ pub struct OutputSettings {
     pub pixel_spacing: u32,
     /// Binary color theme.
     pub theme: BinaryColorTheme,
+    /// Maximum frames per second shown in the window.
+    pub max_fps: u32,
 }
 
 impl OutputSettings {
@@ -51,6 +53,7 @@ pub struct OutputSettingsBuilder {
     scale: Option<u32>,
     pixel_spacing: Option<u32>,
     theme: BinaryColorTheme,
+    max_fps: Option<u32>,
 }
 
 impl OutputSettingsBuilder {
@@ -60,6 +63,7 @@ impl OutputSettingsBuilder {
             scale: None,
             pixel_spacing: None,
             theme: BinaryColorTheme::Default,
+            max_fps: None,
         }
     }
 
@@ -112,12 +116,20 @@ impl OutputSettingsBuilder {
         self
     }
 
+    /// Sets the FPS limit of the window.
+    pub fn max_fps(mut self, max_fps: u32) -> Self {
+        self.max_fps = Some(max_fps);
+
+        self
+    }
+
     /// Builds the output settings.
     pub fn build(self) -> OutputSettings {
         OutputSettings {
             scale: self.scale.unwrap_or(1),
             pixel_spacing: self.pixel_spacing.unwrap_or(0),
             theme: self.theme,
+            max_fps: self.max_fps.unwrap_or(60),
         }
     }
 }