Add checkbox in demo app to turn screen reader on/off

build_demo_web.sh

@@ -13,8 +13,7 @@ rm -f docs/${CRATE_NAME}_bg.wasm
 
 echo "Building rust…"
 BUILD=release
-FEATURES="http,persistence" # screen_reader is experimental
-# FEATURES="http,persistence,screen_reader" # screen_reader is experimental
+FEATURES="http,persistence,screen_reader"
 
 (
   cd egui_demo_app && cargo build \
@@ -30,6 +29,9 @@ TARGET_NAME="${CRATE_NAME}.wasm"
 wasm-bindgen "target/wasm32-unknown-unknown/$BUILD/$TARGET_NAME" \
   --out-dir docs --no-modules --no-typescript
 
-echo "Finished: docs/${CRATE_NAME}.wasm"
+# brew install wabt # to get wasm-strip
+wasm-strip docs/${CRATE_NAME}_bg.wasm
+
+echo "Finished: docs/${CRATE_NAME}_bg.wasm"
 
 open http://localhost:8888/index.html

egui/src/context.rs

@@ -357,6 +357,8 @@ impl Context {
         self.frame_state.lock().available_rect()
     }
 
+    /// Stores all the egui state.
+    /// If you want to store/restore egui, serialize this.
     pub fn memory(&self) -> MutexGuard<'_, Memory> {
         self.memory.lock()
     }
@@ -365,6 +367,7 @@ impl Context {
         self.graphics.lock()
     }
 
+    /// What egui outputs each frame.
     pub fn output(&self) -> MutexGuard<'_, Output> {
         self.output.lock()
     }

egui/src/memory.rs

@@ -18,7 +18,7 @@ use epaint::color::{Color32, Hsva};
 #[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "persistence", serde(default))]
 pub struct Memory {
-    pub(crate) options: Options,
+    pub options: Options,
 
     /// new scale that will be applied at the start of the next frame
     pub(crate) new_pixels_per_point: Option<f32>,
@@ -61,10 +61,11 @@ pub struct Memory {
 
 // ----------------------------------------------------------------------------
 
+/// Some global options that you can read and write.
 #[derive(Clone, Debug, Default)]
 #[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "persistence", serde(default))]
-pub(crate) struct Options {
+pub struct Options {
     /// The default style for new `Ui`:s.
     #[cfg_attr(feature = "persistence", serde(skip))]
     pub(crate) style: std::sync::Arc<Style>,
@@ -72,6 +73,11 @@ pub(crate) struct Options {
     pub(crate) tessellation_options: epaint::TessellationOptions,
     /// Font sizes etc.
     pub(crate) font_definitions: epaint::text::FontDefinitions,
+
+    /// This does not at all change the behavior of egui,
+    /// but is a signal to any backend that we want the [`crate::Output::events`] read out loud.
+    /// Screen readers is an experimental feature of egui, and not supported on all platforms.
+    pub screen_reader: bool,
 }
 
 // ----------------------------------------------------------------------------

egui_demo_app/Cargo.toml

@@ -14,7 +14,7 @@ eframe = { version = "0.10.0", path = "../eframe", features = ["time"] }
 egui_demo_lib = { version = "0.10.0", path = "../egui_demo_lib" }
 
 [features]
-default = ["persistence"]
+default = ["persistence", "screen_reader"]
 http = ["eframe/http", "egui_demo_lib/http"]
 persistence = ["eframe/persistence", "egui_demo_lib/persistence"]
 screen_reader = ["eframe/screen_reader"] # experimental

egui_demo_lib/src/wrap_app.rs

@@ -315,9 +315,17 @@ impl BackendPanel {
             }
         }
 
+        let mut screen_reader = ui.ctx().memory().options.screen_reader;
+        ui.checkbox(&mut screen_reader, "Screen reader").on_hover_text("Experimental feature: checking this will turn on the screen reader on supported platforms");
+        ui.ctx().memory().options.screen_reader = screen_reader;
+
         ui.collapsing("Output events", |ui| {
             ui.set_max_width(450.0);
-            ui.label("Recent output events from egui:");
+            ui.label(
+                "Recent output events from egui. \
+            These are emitted when you switch selected widget with tab, \
+            and can be hooked up to a screen reader on supported platforms.",
+            );
             ui.advance_cursor(8.0);
             for event in &self.output_event_history {
                 ui.label(format!("{:?}", event));

egui_glium/src/backend.rs

@@ -280,7 +280,9 @@ pub fn run(mut app: Box<dyn epi::App>) -> ! {
                 };
             }
 
+            if ctx.memory().options.screen_reader {
                 screen_reader.speak(&egui_output.events_description());
+            }
             if current_cursor_icon != egui_output.cursor_icon {
                 // call only when changed to prevent flickering near frame boundary
                 // when Windows OS tries to control cursor icon for window resizing

egui_web/src/backend.rs

@@ -219,7 +219,9 @@ impl AppRunner {
         let egui_ctx = &self.web_backend.ctx;
         self.app.update(egui_ctx, &mut frame);
         let (egui_output, clipped_meshes) = self.web_backend.end_frame()?;
+        if self.web_backend.ctx.memory().options.screen_reader {
             self.screen_reader.speak(&egui_output.events_description());
+        }
         handle_output(&egui_output);
 
         {