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use crate::{layout, overlay, Clipboard, Element, Event, Layout, Point, Size}; use std::hash::Hasher; /// A set of interactive graphical elements with a specific [`Layout`]. /// /// It can be updated and drawn. /// /// Iced tries to avoid dictating how to write your event loop. You are in /// charge of using this type in your system in any way you want. /// /// [`Layout`]: struct.Layout.html /// /// # Example /// The [`integration` example] uses a [`UserInterface`] to integrate Iced in /// an existing graphical application. /// /// [`integration` example]: https://github.com/hecrj/iced/tree/0.1/examples/integration /// [`UserInterface`]: struct.UserInterface.html #[allow(missing_debug_implementations)] pub struct UserInterface<'a, Message, Renderer> { root: Element<'a, Message, Renderer>, base: Layer, overlay: Option<Layer>, bounds: Size, } impl<'a, Message, Renderer> UserInterface<'a, Message, Renderer> where Renderer: crate::Renderer, { /// Builds a user interface for an [`Element`]. /// /// It is able to avoid expensive computations when using a [`Cache`] /// obtained from a previous instance of a [`UserInterface`]. /// /// [`Element`]: struct.Element.html /// [`Cache`]: struct.Cache.html /// [`UserInterface`]: struct.UserInterface.html /// /// # Example /// Imagine we want to build a [`UserInterface`] for /// [the counter example that we previously wrote](index.html#usage). Here /// is naive way to set up our application loop: /// /// ```no_run /// use iced_native::{UserInterface, Cache, Size}; /// use iced_wgpu::Renderer; /// /// # mod iced_wgpu { /// # pub use iced_native::renderer::Null as Renderer; /// # } /// # /// # use iced_native::Column; /// # /// # pub struct Counter; /// # /// # impl Counter { /// # pub fn new() -> Self { Counter } /// # pub fn view(&self) -> Column<(), Renderer> { /// # Column::new() /// # } /// # } /// // Initialization /// let mut counter = Counter::new(); /// let mut cache = Cache::new(); /// let mut renderer = Renderer::new(); /// let mut window_size = Size::new(1024.0, 768.0); /// /// // Application loop /// loop { /// // Process system events here... /// /// // Build the user interface /// let user_interface = UserInterface::build( /// counter.view(), /// window_size, /// cache, /// &mut renderer, /// ); /// /// // Update and draw the user interface here... /// // ... /// /// // Obtain the cache for the next iteration /// cache = user_interface.into_cache(); /// } /// ``` pub fn build<E: Into<Element<'a, Message, Renderer>>>( root: E, bounds: Size, cache: Cache, renderer: &mut Renderer, ) -> Self { let root = root.into(); let (base, overlay) = { let hash = { let hasher = &mut crate::Hasher::default(); root.hash_layout(hasher); hasher.finish() }; let layout_is_cached = hash == cache.base.hash && bounds == cache.bounds; let (layout, overlay) = if layout_is_cached { (cache.base.layout, cache.overlay) } else { ( renderer.layout( &root, &layout::Limits::new(Size::ZERO, bounds), ), None, ) }; (Layer { layout, hash }, overlay) }; UserInterface { root, base, overlay, bounds, } } /// Updates the [`UserInterface`] by processing each provided [`Event`]. /// /// It returns __messages__ that may have been produced as a result of user /// interactions. You should feed these to your __update logic__. /// /// [`UserInterface`]: struct.UserInterface.html /// [`Event`]: enum.Event.html /// /// # Example /// Let's allow our [counter](index.html#usage) to change state by /// completing [the previous example](#example): /// /// ```no_run /// use iced_native::{UserInterface, Cache, Size, Point}; /// use iced_wgpu::Renderer; /// /// # mod iced_wgpu { /// # pub use iced_native::renderer::Null as Renderer; /// # } /// # /// # use iced_native::Column; /// # /// # pub struct Counter; /// # /// # impl Counter { /// # pub fn new() -> Self { Counter } /// # pub fn view(&self) -> Column<(), Renderer> { /// # Column::new() /// # } /// # pub fn update(&mut self, message: ()) {} /// # } /// let mut counter = Counter::new(); /// let mut cache = Cache::new(); /// let mut renderer = Renderer::new(); /// let mut window_size = Size::new(1024.0, 768.0); /// let mut cursor_position = Point::default(); /// /// // Initialize our event storage /// let mut events = Vec::new(); /// /// loop { /// // Process system events... /// /// let mut user_interface = UserInterface::build( /// counter.view(), /// window_size, /// cache, /// &mut renderer, /// ); /// /// // Update the user interface /// let messages = user_interface.update( /// &events, /// cursor_position, /// None, /// &renderer, /// ); /// /// cache = user_interface.into_cache(); /// /// // Process the produced messages /// for message in messages { /// counter.update(message); /// } /// } /// ``` pub fn update( &mut self, events: &[Event], cursor_position: Point, clipboard: Option<&dyn Clipboard>, renderer: &Renderer, ) -> Vec<Message> { let mut messages = Vec::new(); let base_cursor = if let Some(mut overlay) = self.root.overlay(Layout::new(&self.base.layout)) { let layer = Self::overlay_layer( self.overlay.take(), self.bounds, &mut overlay, renderer, ); for event in events { overlay.on_event( event.clone(), Layout::new(&layer.layout), cursor_position, &mut messages, renderer, clipboard, ); } let base_cursor = if layer.layout.bounds().contains(cursor_position) { // TODO: Type-safe cursor availability Point::new(-1.0, -1.0) } else { cursor_position }; self.overlay = Some(layer); base_cursor } else { cursor_position }; for event in events { self.root.widget.on_event( event.clone(), Layout::new(&self.base.layout), base_cursor, &mut messages, renderer, clipboard, ); } messages } /// Draws the [`UserInterface`] with the provided [`Renderer`]. /// /// It returns the current state of the [`MouseCursor`]. You should update /// the icon of the mouse cursor accordingly in your system. /// /// [`UserInterface`]: struct.UserInterface.html /// [`Renderer`]: trait.Renderer.html /// [`MouseCursor`]: enum.MouseCursor.html /// /// # Example /// We can finally draw our [counter](index.html#usage) by /// [completing the last example](#example-1): /// /// ```no_run /// use iced_native::{UserInterface, Cache, Size, Point}; /// use iced_wgpu::Renderer; /// /// # mod iced_wgpu { /// # pub use iced_native::renderer::Null as Renderer; /// # } /// # /// # use iced_native::Column; /// # /// # pub struct Counter; /// # /// # impl Counter { /// # pub fn new() -> Self { Counter } /// # pub fn view(&self) -> Column<(), Renderer> { /// # Column::new() /// # } /// # pub fn update(&mut self, message: ()) {} /// # } /// let mut counter = Counter::new(); /// let mut cache = Cache::new(); /// let mut renderer = Renderer::new(); /// let mut window_size = Size::new(1024.0, 768.0); /// let mut cursor_position = Point::default(); /// let mut events = Vec::new(); /// /// loop { /// // Process system events... /// /// let mut user_interface = UserInterface::build( /// counter.view(), /// window_size, /// cache, /// &mut renderer, /// ); /// /// let messages = user_interface.update( /// &events, /// cursor_position, /// None, /// &renderer, /// ); /// /// // Draw the user interface /// let mouse_cursor = user_interface.draw(&mut renderer, cursor_position); /// /// cache = user_interface.into_cache(); /// /// for message in messages { /// counter.update(message); /// } /// /// // Update mouse cursor icon... /// // Flush rendering operations... /// } /// ``` pub fn draw( &mut self, renderer: &mut Renderer, cursor_position: Point, ) -> Renderer::Output { let overlay = if let Some(mut overlay) = self.root.overlay(Layout::new(&self.base.layout)) { let layer = Self::overlay_layer( self.overlay.take(), self.bounds, &mut overlay, renderer, ); let overlay_bounds = layer.layout.bounds(); let overlay_primitives = overlay.draw( renderer, &Renderer::Defaults::default(), Layout::new(&layer.layout), cursor_position, ); self.overlay = Some(layer); Some((overlay_primitives, overlay_bounds)) } else { None }; if let Some((overlay_primitives, overlay_bounds)) = overlay { let base_cursor = if overlay_bounds.contains(cursor_position) { Point::new(-1.0, -1.0) } else { cursor_position }; let base_primitives = self.root.widget.draw( renderer, &Renderer::Defaults::default(), Layout::new(&self.base.layout), base_cursor, ); renderer.overlay( base_primitives, overlay_primitives, overlay_bounds, ) } else { self.root.widget.draw( renderer, &Renderer::Defaults::default(), Layout::new(&self.base.layout), cursor_position, ) } } /// Extract the [`Cache`] of the [`UserInterface`], consuming it in the /// process. /// /// [`Cache`]: struct.Cache.html /// [`UserInterface`]: struct.UserInterface.html pub fn into_cache(self) -> Cache { Cache { base: self.base, overlay: self.overlay, bounds: self.bounds, } } fn overlay_layer( cache: Option<Layer>, bounds: Size, overlay: &mut overlay::Element<'_, Message, Renderer>, renderer: &Renderer, ) -> Layer { let new_hash = { let hasher = &mut crate::Hasher::default(); overlay.hash_layout(hasher); hasher.finish() }; let layout = match cache { Some(Layer { hash, layout }) if new_hash == hash => layout, _ => overlay.layout(renderer, bounds), }; Layer { layout, hash: new_hash, } } } #[derive(Debug, Clone)] struct Layer { layout: layout::Node, hash: u64, } /// Reusable data of a specific [`UserInterface`]. /// /// [`UserInterface`]: struct.UserInterface.html #[derive(Debug, Clone)] pub struct Cache { base: Layer, overlay: Option<Layer>, bounds: Size, } impl Cache { /// Creates an empty [`Cache`]. /// /// You should use this to initialize a [`Cache`] before building your first /// [`UserInterface`]. /// /// [`Cache`]: struct.Cache.html /// [`UserInterface`]: struct.UserInterface.html pub fn new() -> Cache { Cache { base: Layer { layout: layout::Node::new(Size::new(0.0, 0.0)), hash: 0, }, overlay: None, bounds: Size::ZERO, } } } impl Default for Cache { fn default() -> Cache { Cache::new() } }