Now App::update will be responsabile for what viewport will be drawned and its content

A big refactoring was needed

examples/confirm_exit/src/main.rs

@@ -2,7 +2,7 @@
 
 use std::sync::{Arc, RwLock};
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -34,7 +34,16 @@ impl eframe::App for MyApp {
         self.data.read().unwrap().allowed_to_close
     }
 
-    fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.heading("Try to close the window");
         });

examples/custom_3d_glow/src/main.rs

@@ -1,7 +1,7 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 #![allow(unsafe_code)]
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 use egui::mutex::Mutex;
 use std::sync::Arc;
@@ -41,7 +41,16 @@ impl MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.horizontal(|ui| {
                 ui.spacing_mut().item_spacing.x = 0.0;

examples/custom_font/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -60,7 +60,16 @@ impl MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.heading("egui using custom fonts");
             ui.text_edit_multiline(&mut self.text);

examples/custom_font_style/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 use egui::{FontFamily, FontId, RichText, TextStyle};
 
 fn main() -> Result<(), eframe::Error> {
@@ -64,7 +64,16 @@ impl MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, content);
     }
 }

examples/custom_window_frame/src/main.rs

@@ -2,7 +2,7 @@
 
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -30,7 +30,16 @@ impl eframe::App for MyApp {
         egui::Rgba::TRANSPARENT.to_array() // Make sure we don't paint anything behind the rounded corners
     }
 
-    fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         custom_window_frame(ctx, frame, "egui with custom frame", |ui| {
             ui.label("This is just the contents of the window.");
             ui.horizontal(|ui| {

examples/download_image/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 use egui_extras::RetainedImage;
 use poll_promise::Promise;
 
@@ -21,7 +21,16 @@ struct MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         let promise = self.promise.get_or_insert_with(|| {
             // Begin download.
             // We download the image using `ehttp`, a library that works both in WASM and on native.

examples/file_dialog/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -23,7 +23,16 @@ struct MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.label("Drag-and-drop files onto the window!");
 

examples/hello_world/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -30,7 +30,16 @@ impl Default for MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.heading("My egui Application");
             ui.horizontal(|ui| {

examples/hello_world_par/src/main.rs

@@ -5,7 +5,7 @@
 use std::sync::{mpsc, Arc, RwLock};
 use std::thread::JoinHandle;
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -136,7 +136,16 @@ impl std::ops::Drop for MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         let data = self.data.clone();
         egui::Window::new("Main thread").show(ctx, move |ui, _, parent_id| {
             if ui.button("Spawn another thread").clicked() {

examples/keyboard_events/src/main.rs

@@ -19,7 +19,16 @@ struct Content {
 }
 
 impl eframe::App for Content {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.heading("Press/Hold/Release example. Press A to test.");
             if ui.button("Clear").clicked() {

examples/puffin_profiler/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -17,7 +17,16 @@ fn main() -> Result<(), eframe::Error> {
 struct MyApp {}
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.heading("Example of how to use the puffin profiler with egui");
             ui.separator();

examples/retained_image/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 use egui_extras::RetainedImage;
 
 fn main() -> Result<(), eframe::Error> {
@@ -35,7 +35,16 @@ impl Default for MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.heading("This is an image:");
             self.image.show(ui);

examples/screenshot/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui::{self, ColorImage};
+use eframe::egui::{self, ColorImage, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -24,7 +24,16 @@ struct MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             if let Some(screenshot) = self.screenshot.take() {
                 self.texture = Some(ui.ctx().load_texture(

examples/serial_windows/src/main.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -46,7 +46,16 @@ struct MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             let label_text = if self.has_next {
                 "When this window is closed the next will be opened after a short delay"

examples/svg/src/main.rs

@@ -4,7 +4,7 @@
 
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
-use eframe::egui;
+use eframe::egui::{self, ViewportRender};
 
 fn main() -> Result<(), eframe::Error> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -37,7 +37,16 @@ impl Default for MyApp {
 }
 
 impl eframe::App for MyApp {
-    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &egui::Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
             ui.heading("SVG example");
             ui.label("The SVG is rasterized and displayed as a texture.");

examples/user_attention/src/main.rs

@@ -1,5 +1,5 @@
 use eframe::{
-    egui::{Button, CentralPanel, Context, UserAttentionType},
+    egui::{Button, CentralPanel, Context, UserAttentionType, ViewportRender},
     CreationContext, NativeOptions,
 };
 
@@ -54,7 +54,16 @@ impl Application {
 }
 
 impl eframe::App for Application {
-    fn update(&mut self, ctx: &Context, frame: &mut eframe::Frame) {
+    fn update(
+        &mut self,
+        ctx: &Context,
+        frame: &mut eframe::Frame,
+        render: Option<&ViewportRender>,
+    ) {
+        if let Some(render) = render {
+            render(ctx, frame.viewport_id(), frame.parent_viewport_id());
+            return;
+        }
         if let Some(request_at) = self.request_at {
             if request_at < SystemTime::now() {
                 self.request_at = None;