Fix up some examples (#3614)

crates/egui/src/context.rs

@@ -1392,11 +1392,16 @@ impl Context {
     /// Sets zoom factor of the UI.
     /// Will become active at the start of the next frame.
     ///
+    /// Note that calling this will not update [`Self::zoom_factor`] until the end of the frame.
+    ///
     /// This is used to calculate the `pixels_per_point`
     /// for the UI as `pixels_per_point = zoom_fator * native_pixels_per_point`.
     ///
     /// The default is 1.0.
     /// Make larger to make everything larger.
+    ///
+    /// It is better to call this than modifying
+    /// [`Options::zoom_factor`].
     #[inline(always)]
     pub fn set_zoom_factor(&self, zoom_factor: f32) {
         self.write(|ctx| {

crates/egui/src/data/input.rs

@@ -156,7 +156,12 @@ impl RawInput {
 pub enum ViewportEvent {
     /// The user clicked the close-button on the window, or similar.
     ///
-    /// It is up to the user to react to this by _not_ showing the viewport in the next frame in the parent viewport.
+    /// If this is the root viewport, the application will exit
+    /// after this frame unless you send a
+    /// [`crate::ViewportCommand::CancelClose`] command.
+    ///
+    /// If this is not the root viewport,
+    /// it is up to the user to hide this viewport the next frame.
     ///
     /// This even will wake up both the child and parent viewport.
     Close,
@@ -216,6 +221,14 @@ pub struct ViewportInfo {
 }
 
 impl ViewportInfo {
+    /// This viewport has been told to close.
+    ///
+    /// If this is the root viewport, the application will exit
+    /// after this frame unless you send a
+    /// [`crate::ViewportCommand::CancelClose`] command.
+    ///
+    /// If this is not the root viewport,
+    /// it is up to the user to hide this viewport the next frame.
     pub fn close_requested(&self) -> bool {
         self.events
             .iter()

crates/egui/src/memory.rs

@@ -178,6 +178,9 @@ pub struct Options {
     ///
     /// The default is 1.0.
     /// Make larger to make everything larger.
+    ///
+    /// Please call [`crate::Context::set_zoom_factor`]
+    /// instead of modifying this directly!
     pub zoom_factor: f32,
 
     /// If `true`, egui will change the scale of the ui ([`crate::Context::zoom_factor`]) when the user

crates/egui/src/viewport.rs

@@ -831,6 +831,9 @@ pub enum ViewportCommand {
     /// For other viewports, the [`crate::ViewportInfo::close_requested`] flag will be set.
     Close,
 
+    /// Calcel the closing that was signaled by [`crate::ViewportInfo::close_requested`].
+    CancelClose,
+
     /// Set the window title.
     Title(String),