Add integration example

It showcases how to integrate iced in an existing graphical application.

examples/integration/src/main.rs

@@ -0,0 +1,204 @@
+mod controls;
+mod scene;
+
+use controls::Controls;
+use scene::Scene;
+
+use iced_wgpu::{
+    wgpu, window::SwapChain, Primitive, Renderer, Settings, Target,
+};
+use iced_winit::{winit, Cache, Clipboard, MouseCursor, Size, UserInterface};
+
+use winit::{
+    event::{DeviceEvent, Event, ModifiersState, WindowEvent},
+    event_loop::{ControlFlow, EventLoop},
+};
+
+pub fn main() {
+    env_logger::init();
+
+    // Initialize winit
+    let event_loop = EventLoop::new();
+    let window = winit::window::Window::new(&event_loop).unwrap();
+    let mut logical_size =
+        window.inner_size().to_logical(window.scale_factor());
+    let mut modifiers = ModifiersState::default();
+
+    // Initialize WGPU
+    let adapter = wgpu::Adapter::request(&wgpu::RequestAdapterOptions {
+        power_preference: wgpu::PowerPreference::Default,
+        backends: wgpu::BackendBit::PRIMARY,
+    })
+    .expect("Request adapter");
+
+    let (mut device, mut queue) =
+        adapter.request_device(&wgpu::DeviceDescriptor {
+            extensions: wgpu::Extensions {
+                anisotropic_filtering: false,
+            },
+            limits: wgpu::Limits::default(),
+        });
+
+    let surface = wgpu::Surface::create(&window);
+
+    let mut swap_chain = {
+        let size = window.inner_size();
+
+        SwapChain::new(&device, &surface, size.width, size.height)
+    };
+    let mut resized = false;
+
+    // Initialize iced
+    let mut events = Vec::new();
+    let mut cache = Some(Cache::default());
+    let mut renderer = Renderer::new(&mut device, Settings::default());
+    let mut output = (Primitive::None, MouseCursor::OutOfBounds);
+    let clipboard = Clipboard::new(&window);
+
+    // Initialize scene and GUI controls
+    let mut scene = Scene::new(&device);
+    let mut controls = Controls::new();
+
+    // Run event loop
+    event_loop.run(move |event, _, control_flow| {
+        // You should change this if you want to render continuosly
+        *control_flow = ControlFlow::Wait;
+
+        match event {
+            Event::DeviceEvent {
+                event: DeviceEvent::ModifiersChanged(new_modifiers),
+                ..
+            } => {
+                modifiers = new_modifiers;
+            }
+            Event::WindowEvent { event, .. } => {
+                match event {
+                    WindowEvent::Resized(new_size) => {
+                        logical_size =
+                            new_size.to_logical(window.scale_factor());
+                        resized = true;
+                    }
+                    WindowEvent::CloseRequested => {
+                        *control_flow = ControlFlow::Exit;
+                    }
+                    _ => {}
+                }
+
+                // Map window event to iced event
+                if let Some(event) = iced_winit::conversion::window_event(
+                    event,
+                    window.scale_factor(),
+                    modifiers,
+                ) {
+                    events.push(event);
+                }
+            }
+            Event::MainEventsCleared => {
+                // If no relevant events happened, we can simply skip this
+                if events.is_empty() {
+                    return;
+                }
+
+                // We need to:
+                // 1. Process events of our user interface.
+                // 2. Update state as a result of any interaction.
+                // 3. Generate a new output for our renderer.
+
+                // First, we build our user interface.
+                let mut user_interface = UserInterface::build(
+                    controls.view(&scene),
+                    Size::new(logical_size.width, logical_size.height),
+                    cache.take().unwrap(),
+                    &mut renderer,
+                );
+
+                // Then, we process the events, obtaining messages in return.
+                let messages = user_interface.update(
+                    events.drain(..),
+                    clipboard.as_ref().map(|c| c as _),
+                    &renderer,
+                );
+
+                let user_interface = if messages.is_empty() {
+                    // If there are no messages, no interactions we care about have
+                    // happened. We can simply leave our user interface as it is.
+                    user_interface
+                } else {
+                    // If there are messages, we need to update our state
+                    // accordingly and rebuild our user interface.
+                    // We can only do this if we drop our user interface first
+                    // by turning it into its cache.
+                    cache = Some(user_interface.into_cache());
+
+                    // In this example, `Controls` is the only part that cares
+                    // about messages, so updating our state is pretty
+                    // straightforward.
+                    for message in messages {
+                        controls.update(message, &mut scene);
+                    }
+
+                    // Once the state has been changed, we rebuild our updated
+                    // user interface.
+                    UserInterface::build(
+                        controls.view(&scene),
+                        Size::new(logical_size.width, logical_size.height),
+                        cache.take().unwrap(),
+                        &mut renderer,
+                    )
+                };
+
+                // Finally, we just need to draw a new output for our renderer,
+                output = user_interface.draw(&mut renderer);
+
+                // update our cache,
+                cache = Some(user_interface.into_cache());
+
+                // and request a redraw
+                window.request_redraw();
+            }
+            Event::RedrawRequested(_) => {
+                if resized {
+                    let size = window.inner_size();
+
+                    swap_chain = SwapChain::new(
+                        &device,
+                        &surface,
+                        size.width,
+                        size.height,
+                    );
+                }
+
+                let (frame, viewport) = swap_chain.next_frame();
+
+                let mut encoder = device.create_command_encoder(
+                    &wgpu::CommandEncoderDescriptor { todo: 0 },
+                );
+
+                // We draw the scene first
+                scene.draw(&mut encoder, &frame.view);
+
+                // And then iced on top
+                let mouse_cursor = renderer.draw(
+                    &mut device,
+                    &mut encoder,
+                    Target {
+                        texture: &frame.view,
+                        viewport,
+                    },
+                    &output,
+                    window.scale_factor(),
+                    &["Some debug information!"],
+                );
+
+                // Then we submit the work
+                queue.submit(&[encoder.finish()]);
+
+                // And update the mouse cursor
+                window.set_cursor_icon(iced_winit::conversion::mouse_cursor(
+                    mouse_cursor,
+                ));
+            }
+            _ => {}
+        }
+    })
+}