leyoda/libcosmic
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
libcosmic/cosmic/iced/index.html
wash2 0fa87f2b35 deploy: 95756b1a57
2026-04-18 20:11:25 +00:00

328 lines
No EOL
36 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="iced is a cross-platform GUI library focused on simplicity and type-safety. Inspired by Elm."><title>cosmic::iced - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-aa0817cf.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="cosmic" data-themes="" data-resource-suffix="" data-rustdoc-version="1.90.0-nightly (3048886e5 2025-07-30)" data-channel="nightly" data-search-js="search-fa3e91e5.js" data-settings-js="settings-5514c975.js" ><script src="../../static.files/storage-68b7e25d.js"></script><script defer src="../../crates.js"></script><script defer src="../../static.files/main-eebb9057.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-32bb7600.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-6580c154.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc mod crate"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle" title="show sidebar"></button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../../cosmic/index.html">cosmic</a><span class="version">1.0.0</span></h2></div><div class="sidebar-elems"><ul class="block"><li><a id="all-types" href="all.html">All Items</a></li></ul><section id="rustdoc-toc"><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#disclaimer" title="Disclaimer">Disclaimer</a></li><li><a href="#the-pocket-guide" title="The Pocket Guide">The Pocket Guide</a><ul><li><a href="#custom-state" title="Custom State">Custom State</a></li><li><a href="#widgets-and-elements" title="Widgets and Elements">Widgets and Elements</a></li><li><a href="#layout-1" title="Layout">Layout</a></li><li><a href="#sizing" title="Sizing">Sizing</a></li><li><a href="#theming" title="Theming">Theming</a></li><li><a href="#styling" title="Styling">Styling</a></li><li><a href="#concurrent-tasks" title="Concurrent Tasks">Concurrent Tasks</a></li><li><a href="#passive-subscriptions" title="Passive Subscriptions">Passive Subscriptions</a></li><li><a href="#scaling-applications" title="Scaling Applications">Scaling Applications</a></li></ul></li></ul><h3><a href="#modules">Crate Items</a></h3><ul class="block"><li><a href="#modules" title="Modules">Modules</a></li><li><a href="#macros" title="Macros">Macros</a></li><li><a href="#structs" title="Structs">Structs</a></li><li><a href="#enums" title="Enums">Enums</a></li><li><a href="#traits" title="Traits">Traits</a></li><li><a href="#functions" title="Functions">Functions</a></li><li><a href="#types" title="Type Aliases">Type Aliases</a></li></ul></section><div id="rustdoc-modnav"></div></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><div class="rustdoc-breadcrumbs"><a href="../index.html">cosmic</a></div><h1>Crate <span>iced</span><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"></span></div><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>iced is a cross-platform GUI library focused on simplicity and type-safety.
Inspired by <a href="https://elm-lang.org/">Elm</a>.</p>
<h2 id="disclaimer"><a class="doc-anchor" href="#disclaimer">§</a>Disclaimer</h2>
<p>iced is <strong>experimental</strong> software. If you expect the documentation to hold your hand
as you learn the ropes, you are in for a frustrating experience.</p>
<p>The library leverages Rust to its full extent: ownership, borrowing, lifetimes, futures,
streams, first-class functions, trait bounds, closures, and more. This documentation
is not meant to teach you any of these. Far from it, it will assume you have <strong>mastered</strong>
all of them.</p>
<p>Furthermore—just like Rust—iced is very unforgiving. It will not let you easily cut corners.
The type signatures alone can be used to learn how to use most of the library.
Everything is connected.</p>
<p>Therefore, iced is easy to learn for <strong>advanced</strong> Rust programmers; but plenty of patient
beginners have learned it and had a good time with it. Since it leverages a lot of what
Rust has to offer in a type-safe way, it can be a great way to discover Rust itself.</p>
<p>If you don’t like the sound of that, you expect to be spoonfed, or you feel frustrated
and struggle to use the library; then I recommend you to wait patiently until <a href="https://book.iced.rs">the book</a>
is finished.</p>
<h2 id="the-pocket-guide"><a class="doc-anchor" href="#the-pocket-guide">§</a>The Pocket Guide</h2>
<p>Start by calling <a href="fn.run.html" title="fn cosmic::iced::run"><code>run</code></a>:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">pub fn </span>main() -&gt; iced::Result {
iced::run(update, view)
}</code></pre></div>
<p>Define an <code>update</code> function to <strong>change</strong> your state:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">fn </span>update(counter: <span class="kw-2">&amp;mut </span>u64, message: Message) {
<span class="kw">match </span>message {
Message::Increment =&gt; <span class="kw-2">*</span>counter += <span class="number">1</span>,
}
}</code></pre></div>
<p>Define a <code>view</code> function to <strong>display</strong> your state:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::widget::{button, text};
<span class="kw">use </span>iced::Element;
<span class="kw">fn </span>view(counter: <span class="kw-2">&amp;</span>u64) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
button(text(counter)).on_press(Message::Increment).into()
}</code></pre></div>
<p>And create a <code>Message</code> enum to <strong>connect</strong> <code>view</code> and <code>update</code> together:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="attr">#[derive(Debug, Clone)]
</span><span class="kw">enum </span>Message {
Increment,
}</code></pre></div>
<h3 id="custom-state"><a class="doc-anchor" href="#custom-state">§</a>Custom State</h3>
<p>You can define your own struct for your state:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="attr">#[derive(Default)]
</span><span class="kw">struct </span>Counter {
value: u64,
}</code></pre></div>
<p>But you have to change <code>update</code> and <code>view</code> accordingly:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">fn </span>update(counter: <span class="kw-2">&amp;mut </span>Counter, message: Message) {
<span class="kw">match </span>message {
Message::Increment =&gt; counter.value += <span class="number">1</span>,
}
}
<span class="kw">fn </span>view(counter: <span class="kw-2">&amp;</span>Counter) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
button(text(counter.value)).on_press(Message::Increment).into()
}</code></pre></div>
<h3 id="widgets-and-elements"><a class="doc-anchor" href="#widgets-and-elements">§</a>Widgets and Elements</h3>
<p>The <code>view</code> function must return an <a href="type.Element.html" title="type cosmic::iced::Element"><code>Element</code></a>. An <a href="type.Element.html" title="type cosmic::iced::Element"><code>Element</code></a> is just a generic <a href="widget/index.html" title="mod cosmic::iced::widget"><code>widget</code></a>.</p>
<p>The <a href="widget/index.html" title="mod cosmic::iced::widget"><code>widget</code></a> module contains a bunch of functions to help you build
and use widgets.</p>
<p>Widgets are configured using the builder pattern:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::widget::{button, column, text};
<span class="kw">use </span>iced::Element;
<span class="kw">fn </span>view(counter: <span class="kw-2">&amp;</span>Counter) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
<span class="macro">column!</span>[
text(counter.value).size(<span class="number">20</span>),
button(<span class="string">"Increment"</span>).on_press(Message::Increment),
]
.spacing(<span class="number">10</span>)
.into()
}</code></pre></div>
<p>A widget can be turned into an <a href="type.Element.html" title="type cosmic::iced::Element"><code>Element</code></a> by calling <code>into</code>.</p>
<p>Widgets and elements are generic over the message type they produce. The
<a href="type.Element.html" title="type cosmic::iced::Element"><code>Element</code></a> returned by <code>view</code> must have the same <code>Message</code> type as
your <code>update</code>.</p>
<h3 id="layout-1"><a class="doc-anchor" href="#layout-1">§</a>Layout</h3>
<p>There is no unified layout system in iced. Instead, each widget implements
its own layout strategy.</p>
<p>Building your layout will often consist in using a combination of
<a href="../widget/struct.Row.html" title="struct cosmic::widget::Row">rows</a>, <a href="../widget/struct.Column.html" title="struct cosmic::widget::Column">columns</a>, and <a href="../widget/struct.Container.html" title="struct cosmic::widget::Container">containers</a>:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::widget::{column, container, row};
<span class="kw">use </span>iced::{Fill, Element};
<span class="kw">fn </span>view(state: <span class="kw-2">&amp;</span>State) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
container(
<span class="macro">column!</span>[
<span class="string">"Top"</span>,
<span class="macro">row!</span>[<span class="string">"Left"</span>, <span class="string">"Right"</span>].spacing(<span class="number">10</span>),
<span class="string">"Bottom"
</span>]
.spacing(<span class="number">10</span>)
)
.padding(<span class="number">10</span>)
.center_x(Fill)
.center_y(Fill)
.into()
}</code></pre></div>
<p>Rows and columns lay out their children horizontally and vertically,
respectively. <a href="../widget/struct.Column.html#method.spacing" title="method cosmic::widget::Column::spacing">Spacing</a> can be easily added between elements.</p>
<p>Containers position or align a single widget inside their bounds.</p>
<h3 id="sizing"><a class="doc-anchor" href="#sizing">§</a>Sizing</h3>
<p>The width and height of widgets can generally be defined using a <a href="enum.Length.html" title="enum cosmic::iced::Length"><code>Length</code></a>.</p>
<ul>
<li><a href="enum.Length.html#variant.Fill" title="variant cosmic::iced::Length::Fill"><code>Fill</code></a> will make the widget take all the available space in a given axis.</li>
<li><a href="enum.Length.html#variant.Shrink" title="variant cosmic::iced::Length::Shrink"><code>Shrink</code></a> will make the widget use its intrinsic size.</li>
</ul>
<p>Most widgets use a <a href="enum.Length.html#variant.Shrink" title="variant cosmic::iced::Length::Shrink"><code>Shrink</code></a> sizing strategy by default, but will inherit
a <a href="enum.Length.html#variant.Fill" title="variant cosmic::iced::Length::Fill"><code>Fill</code></a> strategy from their children.</p>
<p>A fixed numeric <a href="enum.Length.html" title="enum cosmic::iced::Length"><code>Length</code></a> in <a href="struct.Pixels.html" title="struct cosmic::iced::Pixels"><code>Pixels</code></a> can also be used:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::widget::container;
<span class="kw">use </span>iced::Element;
<span class="kw">fn </span>view(state: <span class="kw-2">&amp;</span>State) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
container(<span class="string">"I am 300px tall!"</span>).height(<span class="number">300</span>).into()
}</code></pre></div>
<h3 id="theming"><a class="doc-anchor" href="#theming">§</a>Theming</h3>
<p>The default <a href="enum.Theme.html" title="enum cosmic::iced::Theme"><code>Theme</code></a> of an application can be changed by defining a <code>theme</code>
function and leveraging the <a href="struct.Application.html" title="struct cosmic::iced::Application"><code>Application</code></a> builder, instead of directly
calling <a href="fn.run.html" title="fn cosmic::iced::run"><code>run</code></a>:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::Theme;
<span class="kw">pub fn </span>main() -&gt; iced::Result {
iced::application(new, update, view)
.theme(theme)
.run()
}
<span class="kw">fn </span>new() -&gt; State {
<span class="comment">// ...
</span>}
<span class="kw">fn </span>theme(state: <span class="kw-2">&amp;</span>State) -&gt; Theme {
Theme::TokyoNight
}</code></pre></div>
<p>The <code>theme</code> function takes the current state of the application, allowing the
returned <a href="enum.Theme.html" title="enum cosmic::iced::Theme"><code>Theme</code></a> to be completely dynamic—just like <code>view</code>.</p>
<p>There are a bunch of built-in <a href="enum.Theme.html" title="enum cosmic::iced::Theme"><code>Theme</code></a> variants at your disposal, but you can
also <a href="enum.Theme.html#method.custom" title="associated function cosmic::iced::Theme::custom">create your own</a>.</p>
<h3 id="styling"><a class="doc-anchor" href="#styling">§</a>Styling</h3>
<p>As with layout, iced does not have a unified styling system. However, all
of the built-in widgets follow the same styling approach.</p>
<p>The appearance of a widget can be changed by calling its <code>style</code> method:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::widget::container;
<span class="kw">use </span>iced::Element;
<span class="kw">fn </span>view(state: <span class="kw-2">&amp;</span>State) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
container(<span class="string">"I am a rounded box!"</span>).style(container::rounded_box).into()
}</code></pre></div>
<p>The <code>style</code> method of a widget takes a closure that, given the current active
<a href="enum.Theme.html" title="enum cosmic::iced::Theme"><code>Theme</code></a>, returns the widget style:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::widget::button;
<span class="kw">use </span>iced::{Element, Theme};
<span class="kw">fn </span>view(state: <span class="kw-2">&amp;</span>State) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
button(<span class="string">"I am a styled button!"</span>).style(|theme: <span class="kw-2">&amp;</span>Theme, status| {
<span class="kw">let </span>palette = theme.extended_palette();
<span class="kw">match </span>status {
button::Status::Active =&gt; {
button::Style::default()
.with_background(palette.success.strong.color)
}
<span class="kw">_ </span>=&gt; button::primary(theme, status),
}
})
.into()
}</code></pre></div>
<p>Widgets that can be in multiple different states will also provide the closure
with some <a href="widget/button/enum.Status.html" title="enum cosmic::iced::widget::button::Status"><code>Status</code></a>, allowing you to use a different style for each state.</p>
<p>You can extract the <a href="enum.Theme.html#method.palette" title="method cosmic::iced::Theme::palette"><code>Palette</code></a> colors of a <a href="enum.Theme.html" title="enum cosmic::iced::Theme"><code>Theme</code></a> with the <a href="enum.Theme.html#method.palette" title="method cosmic::iced::Theme::palette"><code>palette</code></a> or
<a href="enum.Theme.html#method.extended_palette" title="method cosmic::iced::Theme::extended_palette"><code>extended_palette</code></a> methods.</p>
<p>Most widgets provide styling functions for your convenience in their respective modules;
like <a href="../widget/container/fn.rounded_box.html" title="fn cosmic::widget::container::rounded_box"><code>container::rounded_box</code></a>, <a href="widget/button/fn.primary.html" title="fn cosmic::iced::widget::button::primary"><code>button::primary</code></a>, or <a href="widget/text/fn.danger.html" title="fn cosmic::iced::widget::text::danger"><code>text::danger</code></a>.</p>
<h3 id="concurrent-tasks"><a class="doc-anchor" href="#concurrent-tasks">§</a>Concurrent Tasks</h3>
<p>The <code>update</code> function can <em>optionally</em> return a <a href="../struct.Task.html" title="struct cosmic::Task"><code>Task</code></a>.</p>
<p>A <a href="../struct.Task.html" title="struct cosmic::Task"><code>Task</code></a> can be leveraged to perform asynchronous work, like running a
future or a stream:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::Task;
<span class="kw">struct </span>State {
weather: <span class="prelude-ty">Option</span>&lt;Weather&gt;,
}
<span class="kw">enum </span>Message {
FetchWeather,
WeatherFetched(Weather),
}
<span class="kw">fn </span>update(state: <span class="kw-2">&amp;mut </span>State, message: Message) -&gt; Task&lt;Message&gt; {
<span class="kw">match </span>message {
Message::FetchWeather =&gt; Task::perform(
fetch_weather(),
Message::WeatherFetched,
),
Message::WeatherFetched(weather) =&gt; {
state.weather = <span class="prelude-val">Some</span>(weather);
Task::none()
}
}
}
<span class="kw">async fn </span>fetch_weather() -&gt; Weather {
<span class="comment">// ...
</span>}</code></pre></div>
<p>Tasks can also be used to interact with the iced runtime. Some modules
expose functions that create tasks for different purposes—like <a href="window/index.html#functions" title="mod cosmic::iced::window">changing
window settings</a>, <a href="daemon/program/runtime/widget/operation/fn.focus_next.html" title="fn cosmic::iced::daemon::program::runtime::widget::operation::focus_next">focusing a widget</a>, or
<a href="widget::selector::find">querying its visible bounds</a>.</p>
<p>Like futures and streams, tasks expose <a href="../struct.Task.html#method.then" title="method cosmic::Task::then">a monadic interface</a>—but they can also be
<a href="../struct.Task.html#method.map" title="method cosmic::Task::map">mapped</a>, <a href="../struct.Task.html#method.chain" title="method cosmic::Task::chain">chained</a>, <a href="../struct.Task.html#method.batch" title="associated function cosmic::Task::batch">batched</a>, <a href="../struct.Task.html#method.abortable" title="method cosmic::Task::abortable">canceled</a>,
and more.</p>
<h3 id="passive-subscriptions"><a class="doc-anchor" href="#passive-subscriptions">§</a>Passive Subscriptions</h3>
<p>Applications can subscribe to passive sources of data—like time ticks or runtime events.</p>
<p>You will need to define a <code>subscription</code> function and use the <a href="struct.Application.html" title="struct cosmic::iced::Application"><code>Application</code></a> builder:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>iced::window;
<span class="kw">use </span>iced::{Size, Subscription};
<span class="attr">#[derive(Debug, Clone)]
</span><span class="kw">enum </span>Message {
WindowResized(Size),
}
<span class="kw">pub fn </span>main() -&gt; iced::Result {
iced::application(new, update, view)
.subscription(subscription)
.run()
}
<span class="kw">fn </span>subscription(state: <span class="kw-2">&amp;</span>State) -&gt; Subscription&lt;Message&gt; {
window::resize_events().map(|(_id, size)| Message::WindowResized(size))
}</code></pre></div>
<p>A <a href="struct.Subscription.html" title="struct cosmic::iced::Subscription"><code>Subscription</code></a> is <a href="struct.Subscription.html#the-lifetime-of-a-subscription" title="struct cosmic::iced::Subscription">a <em>declarative</em> builder of streams</a>
that are not allowed to end on their own. Only the <code>subscription</code> function
dictates the active subscriptions—just like <code>view</code> fully dictates the
visible widgets of your user interface, at every moment.</p>
<p>As with tasks, some modules expose convenient functions that build a <a href="struct.Subscription.html" title="struct cosmic::iced::Subscription"><code>Subscription</code></a> for you—like
<a href="time/fn.every.html" title="fn cosmic::iced::time::every"><code>time::every</code></a> which can be used to listen to time, or <a href="keyboard/fn.listen.html" title="fn cosmic::iced::keyboard::listen"><code>keyboard::listen</code></a> which will notify you
of any keyboard events. But you can also create your own with <a href="struct.Subscription.html#method.run" title="associated function cosmic::iced::Subscription::run"><code>Subscription::run</code></a> and <a href="struct.Subscription.html#method.run_with" title="associated function cosmic::iced::Subscription::run_with"><code>run_with</code></a>.</p>
<h3 id="scaling-applications"><a class="doc-anchor" href="#scaling-applications">§</a>Scaling Applications</h3>
<p>The <code>update</code>, <code>view</code>, and <code>Message</code> triplet composes very nicely.</p>
<p>A common pattern is to leverage this composability to split an
application into different screens:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>contacts::Contacts;
<span class="kw">use </span>conversation::Conversation;
<span class="kw">use </span>iced::{Element, Task};
<span class="kw">struct </span>State {
screen: Screen,
}
<span class="kw">enum </span>Screen {
Contacts(Contacts),
Conversation(Conversation),
}
<span class="kw">enum </span>Message {
Contacts(contacts::Message),
Conversation(conversation::Message)
}
<span class="kw">fn </span>update(state: <span class="kw-2">&amp;mut </span>State, message: Message) -&gt; Task&lt;Message&gt; {
<span class="kw">match </span>message {
Message::Contacts(message) =&gt; {
<span class="kw">if let </span>Screen::Contacts(contacts) = <span class="kw-2">&amp;mut </span>state.screen {
<span class="kw">let </span>action = contacts.update(message);
<span class="kw">match </span>action {
contacts::Action::None =&gt; Task::none(),
contacts::Action::Run(task) =&gt; task.map(Message::Contacts),
contacts::Action::Chat(contact) =&gt; {
<span class="kw">let </span>(conversation, task) = Conversation::new(contact);
state.screen = Screen::Conversation(conversation);
task.map(Message::Conversation)
}
}
} <span class="kw">else </span>{
Task::none()
}
}
Message::Conversation(message) =&gt; {
<span class="kw">if let </span>Screen::Conversation(conversation) = <span class="kw-2">&amp;mut </span>state.screen {
conversation.update(message).map(Message::Conversation)
} <span class="kw">else </span>{
Task::none()
}
}
}
}
<span class="kw">fn </span>view(state: <span class="kw-2">&amp;</span>State) -&gt; Element&lt;<span class="lifetime">'_</span>, Message&gt; {
<span class="kw">match </span><span class="kw-2">&amp;</span>state.screen {
Screen::Contacts(contacts) =&gt; contacts.view().map(Message::Contacts),
Screen::Conversation(conversation) =&gt; conversation.view().map(Message::Conversation),
}
}</code></pre></div>
<p>The <code>update</code> method of a screen can return an <code>Action</code> enum that can be leveraged by the parent to
execute a task or transition to a completely different screen altogether. The variants of <code>Action</code> can
have associated data. For instance, in the example above, the <code>Conversation</code> screen is created when
<code>Contacts::update</code> returns an <code>Action::Chat</code> with the selected contact.</p>
<p>Effectively, this approach lets you “tell a story” to connect different screens together in a type safe
way.</p>
<p>Furthermore, functor methods like <a href="../struct.Task.html#method.map" title="method cosmic::Task::map"><code>Task::map</code></a>, <a href="daemon/program/graphics/core/struct.Element.html#method.map" title="method cosmic::iced::daemon::program::graphics::core::Element::map"><code>Element::map</code></a>, and <a href="struct.Subscription.html#method.map" title="method cosmic::iced::Subscription::map"><code>Subscription::map</code></a> make composition
seamless.</p>
</div></details><h2 id="modules" class="section-header">Modules<a href="#modules" class="anchor">§</a></h2><dl class="item-table"><dt><a class="mod" href="advanced/index.html" title="mod cosmic::iced::advanced">advanced</a></dt><dd>Leverage advanced concepts like custom widgets.</dd><dt><a class="mod" href="application/index.html" title="mod cosmic::iced::application">application</a></dt><dd>Create and run iced applications step by step.</dd><dt><a class="mod" href="clipboard/index.html" title="mod cosmic::iced::clipboard">clipboard</a></dt><dd>Access the clipboard.</dd><dt><a class="mod" href="daemon/index.html" title="mod cosmic::iced::daemon">daemon</a></dt><dd>Create and run daemons that run in the background.</dd><dt><a class="mod" href="debug/index.html" title="mod cosmic::iced::debug">debug</a></dt><dd>Debug your applications.</dd><dt><a class="mod" href="event/index.html" title="mod cosmic::iced::event">event</a></dt><dd>Handle events of a user interface.</dd><dt><a class="mod" href="executor/index.html" title="mod cosmic::iced::executor">executor</a></dt><dd>Choose your preferred executor to power your application.</dd><dt><a class="mod" href="font/index.html" title="mod cosmic::iced::font">font</a></dt><dd>Load and use fonts.</dd><dt><a class="mod" href="keyboard/index.html" title="mod cosmic::iced::keyboard">keyboard</a></dt><dd>Listen and react to keyboard events.</dd><dt><a class="mod" href="mouse/index.html" title="mod cosmic::iced::mouse">mouse</a></dt><dd>Listen and react to mouse events.</dd><dt><a class="mod" href="overlay/index.html" title="mod cosmic::iced::overlay">overlay</a></dt><dd>Display interactive elements on top of other widgets.</dd><dt><a class="mod" href="platform_specific/index.html" title="mod cosmic::iced::platform_specific">platform_<wbr>specific</a></dt><dt><a class="mod" href="system/index.html" title="mod cosmic::iced::system">system</a></dt><dd>Retrieve system information.</dd><dt><a class="mod" href="task/index.html" title="mod cosmic::iced::task">task</a></dt><dd>Create runtime tasks.</dd><dt><a class="mod" href="time/index.html" title="mod cosmic::iced::time">time</a></dt><dd>Listen and react to time.</dd><dt><a class="mod" href="touch/index.html" title="mod cosmic::iced::touch">touch</a></dt><dd>Listen and react to touch events.</dd><dt><a class="mod" href="widget/index.html" title="mod cosmic::iced::widget">widget</a></dt><dd>Use the built-in widgets or create your own.</dd><dt><a class="mod" href="window/index.html" title="mod cosmic::iced::window">window</a></dt><dd>Configure the window of your application in native platforms.</dd></dl><h2 id="macros" class="section-header">Macros<a href="#macros" class="anchor">§</a></h2><dl class="item-table"><dt><a class="macro" href="macro.color.html" title="macro cosmic::iced::color">color</a></dt><dd>Creates a <a href="struct.Color.html" title="struct cosmic::iced::Color"><code>Color</code></a> with shorter and cleaner syntax.</dd></dl><h2 id="structs" class="section-header">Structs<a href="#structs" class="anchor">§</a></h2><dl class="item-table"><dt><a class="struct" href="struct.Animation.html" title="struct cosmic::iced::Animation">Animation</a></dt><dd>The animation of some particular state.</dd><dt><a class="struct" href="struct.Application.html" title="struct cosmic::iced::Application">Application</a></dt><dd>The underlying definition and configuration of an iced application.</dd><dt><a class="struct" href="struct.Border.html" title="struct cosmic::iced::Border">Border</a></dt><dd>A border.</dd><dt><a class="struct" href="struct.Color.html" title="struct cosmic::iced::Color">Color</a></dt><dd>A color in the <code>sRGB</code> color space.</dd><dt><a class="struct" href="struct.Daemon.html" title="struct cosmic::iced::Daemon">Daemon</a></dt><dd>The underlying definition and configuration of an iced daemon.</dd><dt><a class="struct" href="struct.Degrees.html" title="struct cosmic::iced::Degrees">Degrees</a></dt><dd>Degrees</dd><dt><a class="struct" href="struct.Font.html" title="struct cosmic::iced::Font">Font</a></dt><dd>A font.</dd><dt><a class="struct" href="struct.Limits.html" title="struct cosmic::iced::Limits">Limits</a></dt><dd>A set of size constraints for layouting.</dd><dt><a class="struct" href="struct.Padding.html" title="struct cosmic::iced::Padding">Padding</a></dt><dd>An amount of space to pad for each side of a box</dd><dt><a class="struct" href="struct.Pixels.html" title="struct cosmic::iced::Pixels">Pixels</a></dt><dd>An amount of logical pixels.</dd><dt><a class="struct" href="struct.Point.html" title="struct cosmic::iced::Point">Point</a></dt><dd>A 2D point.</dd><dt><a class="struct" href="struct.Preset.html" title="struct cosmic::iced::Preset">Preset</a></dt><dd>A specific boot strategy for a <a href="trait.Program.html" title="trait cosmic::iced::Program"><code>Program</code></a>.</dd><dt><a class="struct" href="struct.Radians.html" title="struct cosmic::iced::Radians">Radians</a></dt><dd>Radians</dd><dt><a class="struct" href="struct.Radius.html" title="struct cosmic::iced::Radius">Radius</a></dt><dd>The border radii for the corners of a graphics primitive in the order:
top-left, top-right, bottom-right, bottom-left.</dd><dt><a class="struct" href="struct.Rectangle.html" title="struct cosmic::iced::Rectangle">Rectangle</a></dt><dd>An axis-aligned rectangle.</dd><dt><a class="struct" href="struct.Settings.html" title="struct cosmic::iced::Settings">Settings</a></dt><dd>The settings of an iced program.</dd><dt><a class="struct" href="struct.Shadow.html" title="struct cosmic::iced::Shadow">Shadow</a></dt><dd>A shadow.</dd><dt><a class="struct" href="struct.Size.html" title="struct cosmic::iced::Size">Size</a></dt><dd>An amount of space in 2 dimensions.</dd><dt><a class="struct" href="struct.Subscription.html" title="struct cosmic::iced::Subscription">Subscription</a></dt><dd>A request to listen to external events.</dd><dt><a class="struct" href="struct.Task.html" title="struct cosmic::iced::Task">Task</a></dt><dd>A set of concurrent actions to be performed by the iced runtime.</dd><dt><a class="struct" href="struct.Transformation.html" title="struct cosmic::iced::Transformation">Transformation</a></dt><dd>A 2D transformation matrix.</dd><dt><a class="struct" href="struct.Vector.html" title="struct cosmic::iced::Vector">Vector</a></dt><dd>A 2D vector.</dd></dl><h2 id="enums" class="section-header">Enums<a href="#enums" class="anchor">§</a></h2><dl class="item-table"><dt><a class="enum" href="enum.Alignment.html" title="enum cosmic::iced::Alignment">Alignment</a></dt><dd>Alignment on the axis of a container.</dd><dt><a class="enum" href="enum.Background.html" title="enum cosmic::iced::Background">Background</a></dt><dd>The background of some element.</dd><dt><a class="enum" href="enum.ContentFit.html" title="enum cosmic::iced::ContentFit">Content<wbr>Fit</a></dt><dd>The strategy used to fit the contents of a widget to its bounding box.</dd><dt><a class="enum" href="enum.Error.html" title="enum cosmic::iced::Error">Error</a></dt><dd>An error that occurred while running an application.</dd><dt><a class="enum" href="enum.Event.html" title="enum cosmic::iced::Event">Event</a></dt><dd>A user interface event.</dd><dt><a class="enum" href="enum.Gradient.html" title="enum cosmic::iced::Gradient">Gradient</a></dt><dd>A fill which transitions colors progressively along a direction, either linearly, radially (TBD),
or conically (TBD).</dd><dt><a class="enum" href="enum.Length.html" title="enum cosmic::iced::Length">Length</a></dt><dd>The strategy used to fill space in a specific dimension.</dd><dt><a class="enum" href="enum.Never.html" title="enum cosmic::iced::Never">Never</a></dt><dd>The error type for errors that can never happen.</dd><dt><a class="enum" href="enum.Rotation.html" title="enum cosmic::iced::Rotation">Rotation</a></dt><dd>The strategy used to rotate the content.</dd><dt><a class="enum" href="enum.Theme.html" title="enum cosmic::iced::Theme">Theme</a></dt><dd>A built-in theme.</dd></dl><h2 id="traits" class="section-header">Traits<a href="#traits" class="anchor">§</a></h2><dl class="item-table"><dt><a class="trait" href="trait.Executor.html" title="trait cosmic::iced::Executor">Executor</a></dt><dd>A type that can run futures.</dd><dt><a class="trait" href="trait.Function.html" title="trait cosmic::iced::Function">Function</a></dt><dd>A trait extension for binary functions (<code>Fn(A, B) -&gt; O</code>).</dd><dt><a class="trait" href="trait.Program.html" title="trait cosmic::iced::Program">Program</a></dt><dd>The internal definition of a <a href="trait.Program.html" title="trait cosmic::iced::Program"><code>Program</code></a>.</dd><dt><a class="trait" href="trait.Window.html" title="trait cosmic::iced::Window">Window</a></dt><dd>A window managed by iced.</dd></dl><h2 id="functions" class="section-header">Functions<a href="#functions" class="anchor">§</a></h2><dl class="item-table"><dt><a class="fn" href="fn.application.html" title="fn cosmic::iced::application">application</a></dt><dd>Creates an iced <a href="struct.Application.html" title="struct cosmic::iced::Application"><code>Application</code></a> given its boot, update, and view logic.</dd><dt><a class="fn" href="fn.daemon.html" title="fn cosmic::iced::daemon">daemon</a></dt><dd>Creates an iced <a href="struct.Daemon.html" title="struct cosmic::iced::Daemon"><code>Daemon</code></a> given its title, update, and view logic.</dd><dt><a class="fn" href="fn.exit.html" title="fn cosmic::iced::exit">exit</a></dt><dd>Creates a <a href="../struct.Task.html" title="struct cosmic::Task"><code>Task</code></a> that exits the iced runtime.</dd><dt><a class="fn" href="fn.never.html" title="fn cosmic::iced::never">never</a></dt><dd>A function that can <em>never</em> be called.</dd><dt><a class="fn" href="fn.run.html" title="fn cosmic::iced::run">run</a></dt><dd>Runs a basic iced application with default <a href="struct.Settings.html" title="struct cosmic::iced::Settings"><code>Settings</code></a> given its title,
update, and view logic.</dd></dl><h2 id="types" class="section-header">Type Aliases<a href="#types" class="anchor">§</a></h2><dl class="item-table"><dt><a class="type" href="type.Element.html" title="type cosmic::iced::Element">Element</a></dt><dd>A generic widget.</dd><dt><a class="type" href="type.Renderer.html" title="type cosmic::iced::Renderer">Renderer</a></dt><dd>The default graphics renderer for <a href="https://github.com/iced-rs/iced"><code>iced</code></a>.</dd><dt><a class="type" href="type.Result.html" title="type cosmic::iced::Result">Result</a></dt><dd>The result of running an iced program.</dd></dl></section></div></main></body></html>
Reference in a new issue View git blame Copy permalink