[egui_web] Simplify the arguments you pass to start()

demo_web/src/lib.rs

@@ -11,8 +11,6 @@ use wasm_bindgen::prelude::*;
 #[wasm_bindgen]
 pub fn start(canvas_id: &str) -> Result<(), wasm_bindgen::JsValue> {
     let app = egui::DemoApp::default();
-    let backend = egui_web::WebBackend::new(canvas_id)?;
-    let runner = egui_web::AppRunner::new(backend, Box::new(app))?;
-    egui_web::start(runner)?;
+    egui_web::start(canvas_id, Box::new(app))?;
     Ok(())
 }

egui_web/CHANGELOG.md

@@ -14,6 +14,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Changed ⭐
 
 * Set a maximum canvas size to alleviate performance issues on some machines
+* Simplify `egui_web::start` arguments
 
 
 ## 0.4.0 - 2020-11-28

egui_web/src/backend.rs

@@ -221,9 +221,17 @@ impl AppRunner {
     }
 }
 
+/// Install event listeners to register different input events
+/// and starts running the given app.
+pub fn start(canvas_id: &str, app: Box<dyn App>) -> Result<AppRunnerRef, JsValue> {
+    let backend = WebBackend::new(canvas_id)?;
+    let runner = AppRunner::new(backend, app)?;
+    start_runner(runner)
+}
+
 /// Install event listeners to register different input events
 /// and starts running the given `AppRunner`.
-pub fn start(app_runner: AppRunner) -> Result<AppRunnerRef, JsValue> {
+fn start_runner(app_runner: AppRunner) -> Result<AppRunnerRef, JsValue> {
     let runner_ref = AppRunnerRef(Arc::new(Mutex::new(app_runner)));
     install_canvas_events(&runner_ref)?;
     install_document_events(&runner_ref)?;

example_web/src/lib.rs

@@ -13,8 +13,6 @@ use wasm_bindgen::prelude::*;
 #[wasm_bindgen]
 pub fn start(canvas_id: &str) -> Result<(), wasm_bindgen::JsValue> {
     let app = example_app::ExampleApp::default();
-    let backend = egui_web::WebBackend::new(canvas_id)?;
-    let runner = egui_web::AppRunner::new(backend, Box::new(app))?;
-    egui_web::start(runner)?;
+    egui_web::start(canvas_id, Box::new(app))?;
     Ok(())
 }