<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="A temporary state of an application. There’s a stack of these, with the most recent being the active one."><metaname="keywords"content="rust, rustlang, rust-lang, State"><title>State in widgetry::app_state - Rust</title><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../SourceSerif4-Regular.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../FiraSans-Regular.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../FiraSans-Medium.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../SourceCodePro-Regular.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../SourceSerif4-Bold.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../SourceCodePro-Semibold.ttf.woff2"><linkrel="stylesheet"type="text/css"href="../../normalize.css"><linkrel="stylesheet"type="text/css"href="../../rustdoc.css"id="mainThemeStyle"><linkrel="stylesheet"type="text/css"href="../../ayu.css"disabled><linkrel="stylesheet"type="text/css"href="../../dark.css"disabled><linkrel="stylesheet"type="text/css"href="../../light.css"id="themeStyle"><scriptid="default-settings"></script><scriptsrc="../../storage.js"></script><scriptsrc="../../crates.js"></script><scriptdefersrc="../../main.js"></script>
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</a><h2class="location"><ahref="#">State</a></h2><divclass="sidebar-elems"><section><divclass="block"><h3class="sidebar-title"><ahref="#required-methods">Required Methods</a></h3><ul><li><ahref="#tymethod.draw">draw</a></li><li><ahref="#tymethod.event">event</a></li></ul></div><divclass="block"><h3class="sidebar-title"><ahref="#provided-methods">Provided Methods</a></h3><ul><li><ahref="#method.draw_baselayer">draw_baselayer</a></li><li><ahref="#method.on_destroy">on_destroy</a></li><li><ahref="#method.recreate">recreate</a></li></ul></div><divclass="block"><h3class="sidebar-title"><ahref="#implementations">Methods</a></h3><ul><li><ahref="#method.downcast">downcast</a></li><li><ahref="#method.downcast_mut">downcast_mut</a></li><li><ahref="#method.downcast_rc">downcast_rc</a></li><li><ahref="#method.downcast_ref">downcast_ref</a></li><li><ahref="#method.is">is</a></li></ul></div><divclass="block"><h3class="sidebar-title"><ahref="#implementors">Implementors</a></h3></div></section><h2class="location"><ahref="index.html">In widgetry::app_state</a></h2><divid="sidebar-vars"data-name="State"data-ty="trait"data-relpath=""></div><scriptdefersrc="sidebar-items.js"></script></div></nav><main><divclass="width-limiter"><divclass="sub-container"><aclass="sub-logo-container"href="../../widgetry/index.html"><imgclass="rust-logo"src="../../rust-logo.svg"alt="logo"></a><navclass="sub"><divclass="theme-picker hidden"><buttonid="theme-picker"aria-label="Pick another theme!"aria-haspopup="menu"title="themes"><imgwidth="22"height="22"alt="Pick another theme!"src="../../brush.svg"></button><divid="theme-choices"role="menu"></div></div><formclass="search-form"><divclass="search-container"><span></span><inputclass="search-input"name="search"autocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"><buttontype="button"id="help-button"title="help">?</button><aid="settings-menu"href="../../settings.html"title="settings"><imgwidth="22"height="22"alt="Change settings"src="../../wheel.svg"></a></div></form></nav></div><sectionid="main-content"class="content"><divclass="main-heading">
<h1class="fqn"><spanclass="in-band">Trait <ahref="../index.html">widgetry</a>::<wbr><ahref="index.html">app_state</a>::<wbr><aclass="trait"href="#">State</a><buttonid="copy-path"onclick="copy_path(this)"title="Copy item path to clipboard"><imgsrc="../../clipboard.svg"width="19"height="18"alt="Copy item path"></button></span></h1><spanclass="out-of-band"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#178-198">source</a> · <aid="toggle-all-docs"href="javascript:void(0)"title="collapse all docs">[<spanclass="inner">−</span>]</a></span></div><divclass="docblock item-decl"><preclass="rust trait"><code>pub trait State<A>: Downcast {
}</code></pre></div><detailsclass="rustdoc-toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>A temporary state of an application. There’s a stack of these, with the most recent being the
</div></details><h2id="required-methods"class="small-section-header">Required methods<ahref="#required-methods"class="anchor"></a></h2><divclass="methods"><detailsclass="rustdoc-toggle"open><summary><divid="tymethod.event"class="method has-srclink"><divclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#180">source</a></div><h4class="code-header">fn <ahref="#tymethod.event"class="fnname">event</a>(<br> &mut self, <br> ctx: &mut <aclass="struct"href="../event_ctx/struct.EventCtx.html"title="struct widgetry::event_ctx::EventCtx">EventCtx</a><'_>, <br> shared_app_state: <aclass="primitive"href="https://doc.rust-lang.org/1.61.0/std/primitive.reference.html">&mut </a>A<br>) -><aclass="enum"href="enum.Transition.html"title="enum widgetry::app_state::Transition">Transition</a><A></h4></div></summary><divclass="docblock"><p>Respond to a UI event, such as input or time passing.</p>
</div></details></div><h2id="provided-methods"class="small-section-header">Provided methods<ahref="#provided-methods"class="anchor"></a></h2><divclass="methods"><detailsclass="rustdoc-toggle"open><summary><divid="method.draw_baselayer"class="method has-srclink"><divclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#185-187">source</a></div><h4class="code-header">fn <ahref="#method.draw_baselayer"class="fnname">draw_baselayer</a>(&self) -><aclass="enum"href="enum.DrawBaselayer.html"title="enum widgetry::app_state::DrawBaselayer">DrawBaselayer</a></h4></div></summary><divclass="docblock"><p>Specifies what to draw before draw()</p>
</div></details><detailsclass="rustdoc-toggle"open><summary><divid="method.on_destroy"class="method has-srclink"><divclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#190">source</a></div><h4class="code-header">fn <ahref="#method.on_destroy"class="fnname">on_destroy</a>(&mut self, _: &mut <aclass="struct"href="../event_ctx/struct.EventCtx.html"title="struct widgetry::event_ctx::EventCtx">EventCtx</a><'_>, _: <aclass="primitive"href="https://doc.rust-lang.org/1.61.0/std/primitive.reference.html">&mut </a>A)</h4></div></summary><divclass="docblock"><p>Before this state is popped or replaced, call this.</p>
</div></details><detailsclass="rustdoc-toggle"open><summary><divid="method.recreate"class="method has-srclink"><divclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#195-197">source</a></div><h4class="code-header">fn <ahref="#method.recreate"class="fnname">recreate</a>(&mut self, _: &mut <aclass="struct"href="../event_ctx/struct.EventCtx.html"title="struct widgetry::event_ctx::EventCtx">EventCtx</a><'_>, _: <aclass="primitive"href="https://doc.rust-lang.org/1.61.0/std/primitive.reference.html">&mut </a>A) -><aclass="struct"href="https://doc.rust-lang.org/1.61.0/alloc/boxed/struct.Box.html"title="struct alloc::boxed::Box">Box</a><dyn <aclass="trait"href="trait.State.html"title="trait widgetry::app_state::State">State</a><A>></h4></div></summary><divclass="docblock"><p>Respond to <code>Transition::Recreate</code> by assuming state in the app has changed, but preserving
</div></details></div><h2id="implementations"class="small-section-header">Implementations<ahref="#implementations"class="anchor"></a></h2><divid="implementations-list"><detailsclass="rustdoc-toggle implementors-toggle"open><summary><sectionid="impl"class="impl has-srclink"><spanclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#200">source</a></span><ahref="#impl"class="anchor"></a><h3class="code-header in-band">impl<A> dyn <aclass="trait"href="trait.State.html"title="trait widgetry::app_state::State">State</a><A><spanclass="where fmt-newline">where<br> A: <aclass="trait"href="https://doc.rust-lang.org/1.61.0/core/any/trait.Any.html"title="trait core::any::Any">Any</a> + 'static, </span></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.is"class="method has-srclink"><spanclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#200">source</a></span><ahref="#method.is"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.is"class="fnname">is</a><__T: <aclass="trait"href="trait.State.html"title="trait widgetry::app_state::State">State</a><A>>(&self) -><aclass="primitive"href="https://doc.rust-lang.org/1.61.0/std/primitive.bool.html">bool</a></h4></section></summary><divclass="docblock"><p>Returns true if the trait object wraps an object of type <code>__T</code>.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.downcast"class="method has-srclink"><spanclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#200">source</a></span><ahref="#method.downcast"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.downcast"class="fnname">downcast</a><__T: <aclass="trait"href="trait.State.html"title="trait widgetry::app_state::State">State</a><A>>(self: <aclass="struct"href="https://doc.rust-lang.org/1.61.0/alloc/boxed/struct.Box.html"title="struct alloc::boxed::Box">Box</a><Self>) -><aclass="enum"href="https://doc.rust-lang.org/1.61.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><<aclass="struct"href="https://doc.rust-lang.org/1.61.0/alloc/boxed/struct.Box.html"title="struct alloc::boxed::Box">Box</a><__T>, <aclass="struct"href="https://doc.rust-lang.org/1.61.0/alloc/boxed/struct.Box.html"title="struct alloc::boxed::Box">Box</a><Self>></h4></section></summary><divclass="docblock"><p>Returns a boxed object from a boxed trait object if the underlying object is of type
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.downcast_rc"class="method has-srclink"><spanclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#200">source</a></span><ahref="#method.downcast_rc"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.downcast_rc"class="fnname">downcast_rc</a><__T: <aclass="trait"href="trait.State.html"title="trait widgetry::app_state::State">State</a><A>>(self: <aclass="struct"href="https://doc.rust-lang.org/1.61.0/alloc/rc/struct.Rc.html"title="struct alloc::rc::Rc">Rc</a><Self>) -><aclass="enum"href="https://doc.rust-lang.org/1.61.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><<aclass="struct"href="https://doc.rust-lang.org/1.61.0/alloc/rc/struct.Rc.html"title="struct alloc::rc::Rc">Rc</a><__T>, <aclass="struct"href="https://doc.rust-lang.org/1.61.0/alloc/rc/struct.Rc.html"title="struct alloc::rc::Rc">Rc</a><Self>></h4></section></summary><divclass="docblock"><p>Returns an <code>Rc</code>-ed object from an <code>Rc</code>-ed trait object if the underlying object is of
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.downcast_ref"class="method has-srclink"><spanclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#200">source</a></span><ahref="#method.downcast_ref"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.downcast_ref"class="fnname">downcast_ref</a><__T: <aclass="trait"href="trait.State.html"title="trait widgetry::app_state::State">State</a><A>>(&self) -><aclass="enum"href="https://doc.rust-lang.org/1.61.0/core/option/enum.Option.html"title="enum core::option::Option">Option</a><<aclass="primitive"href="https://doc.rust-lang.org/1.61.0/std/primitive.reference.html">&</a>__T></h4></section></summary><divclass="docblock"><p>Returns a reference to the object within the trait object if it is of type <code>__T</code>, or
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.downcast_mut"class="method has-srclink"><spanclass="rightside"><aclass="srclink"href="../../src/widgetry/app_state.rs.html#200">source</a></span><ahref="#method.downcast_mut"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.downcast_mut"class="fnname">downcast_mut</a><__T: <aclass="trait"href="trait.State.html"title="trait widgetry::app_state::State">State</a><A>>(&mut self) -><aclass="enum"href="https://doc.rust-lang.org/1.61.0/core/option/enum.Option.html"title="enum core::option::Option">Option</a><<aclass="primitive"href="https://doc.rust-lang.org/1.61.0/std/primitive.reference.html">&mut </a>__T></h4></section></summary><divclass="docblock"><p>Returns a mutable reference to the object within the trait object if it is of type
