Improve documentation and logging

crates/eframe/src/lib.rs

@@ -48,8 +48,9 @@
 //! /// Call this once from the HTML.
 //! #[cfg(target_arch = "wasm32")]
 //! #[wasm_bindgen]
-//! pub fn start(canvas_id: &str) -> Result<(), eframe::wasm_bindgen::JsValue> {
-//!     eframe::start_web(canvas_id, Box::new(|cc| Box::new(MyApp::new(cc))))
+//! pub fn start(canvas_id: &str) -> Result<AppRunnerRef, eframe::wasm_bindgen::JsValue> {
+//!     let web_options = eframe::WebOptions::default();
+//!     eframe::start_web(canvas_id, web_options, Box::new(|cc| Box::new(MyEguiApp::new(cc))))
 //! }
 //! ```
 //!

crates/eframe/src/web/mod.rs

@@ -108,6 +108,10 @@ pub fn resize_canvas_to_screen_size(canvas_id: &str, max_size_points: egui::Vec2
         y: height as f32,
     };
 
+    if width <= 0 || height <= 0 {
+        tracing::error!("egui canvas parent size is {}x{}. Try adding `html, body {{ height: 100%; width: 100% }}` to your CSS!", width, height);
+    }
+
     let pixels_per_point = native_pixels_per_point();
 
     let max_size_pixels = pixels_per_point * max_size_points;

crates/egui/src/containers/scroll_area.rs

@@ -479,7 +479,7 @@ impl ScrollArea {
 
     /// This can be used to only paint the visible part of the contents.
     ///
-    /// `add_contents` is past the viewport, which is the relative view of the content.
+    /// `add_contents` is given the viewport rectangle, which is the relative view of the content.
     /// So if the passed rect has min = zero, then show the top left content (the user has not scrolled).
     pub fn show_viewport<R>(
         self,

crates/egui_extras/src/image.rs

@@ -29,6 +29,8 @@ impl RetainedImage {
 
     /// Load a (non-svg) image.
     ///
+    /// `image_bytes` should be the raw contents of an image file (`.png`, `.jpg`, …).
+    ///
     /// Requires the "image" feature. You must also opt-in to the image formats you need
     /// with e.g. `image = { version = "0.24", features = ["jpeg", "png"] }`.
     ///

sh/docs.sh

@@ -3,7 +3,7 @@ set -eu
 script_path=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
 cd "$script_path/.."
 
-cargo doc -p eframe --target wasm32-unknown-unknown --lib --no-deps --all-features
+cargo doc -p eframe --target wasm32-unknown-unknown --lib --no-deps
 cargo doc -p emath -p epaint -p egui -p eframe -p egui-winit -p egui_extras -p egui_glium -p egui_glow --lib --no-deps --all-features --open
 
 # cargo watch -c -x 'doc -p emath -p epaint -p egui --lib --no-deps --all-features'