libcosmic/cosmic/widget/canvas/path/lyon_path/iterator/index.html
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<!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="Tools to iterate over paths."><title>cosmic::widget::canvas::path::lyon_path::iterator - 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="../sidebar-items.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"><!--[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"><section id="rustdoc-toc"><h2 class="location"><a href="#">Module iterator</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#lyon-path-iterators" title="Lyon path iterators">Lyon path iterators</a><ul><li><a href="#overview" title="Overview">Overview</a></li><li><a href="#examples" title="Examples">Examples</a></li></ul></li></ul><h3><a href="#structs">Module Items</a></h3><ul class="block"><li><a href="#structs" title="Structs">Structs</a></li><li><a href="#traits" title="Traits">Traits</a></li></ul></section><div id="rustdoc-modnav"><h2><a href="../index.html">In cosmic::<wbr>widget::<wbr>canvas::<wbr>path::<wbr>lyon_<wbr>path</a></h2></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>::<wbr><a href="../../../../index.html">widget</a>::<wbr><a href="../../../index.html">canvas</a>::<wbr><a href="../../index.html">path</a>::<wbr><a href="../index.html">lyon_path</a></div><h1>Module <span>iterator</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>Tools to iterate over paths.</p>
<h2 id="lyon-path-iterators"><a class="doc-anchor" href="#lyon-path-iterators">§</a>Lyon path iterators</h2><h3 id="overview"><a class="doc-anchor" href="#overview">§</a>Overview</h3>
<p>This module provides a collection of traits to extend the <code>Iterator</code> trait when
iterating over paths.</p>
<h3 id="examples"><a class="doc-anchor" href="#examples">§</a>Examples</h3>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>lyon_path::iterator::<span class="kw-2">*</span>;
<span class="kw">use </span>lyon_path::math::{point, vector};
<span class="kw">use </span>lyon_path::{Path, PathEvent};
<span class="comment">// Start with a path.
</span><span class="kw">let </span><span class="kw-2">mut </span>builder = Path::builder();
builder.begin(point(<span class="number">0.0</span>, <span class="number">0.0</span>));
builder.line_to(point(<span class="number">10.0</span>, <span class="number">0.0</span>));
builder.cubic_bezier_to(point(<span class="number">10.0</span>, <span class="number">10.0</span>), point(<span class="number">0.0</span>, <span class="number">10.0</span>), point(<span class="number">0.0</span>, <span class="number">5.0</span>));
builder.end(<span class="bool-val">true</span>);
<span class="kw">let </span>path = builder.build();
<span class="comment">// A simple std::iter::Iterator&lt;PathEvent&gt;,
</span><span class="kw">let </span>simple_iter = path.iter();
<span class="comment">// Make it an iterator over simpler primitives flattened events,
// which do not contain any curve. To do so we approximate each curve
// linear segments according to a tolerance threshold which controls
// the tradeoff between fidelity of the approximation and amount of
// generated events. Let's use a tolerance threshold of 0.01.
// The beauty of this approach is that the flattening happens lazily
// while iterating without allocating memory for the path.
</span><span class="kw">let </span>flattened_iter = path.iter().flattened(<span class="number">0.01</span>);
<span class="kw">for </span>evt <span class="kw">in </span>flattened_iter {
<span class="kw">match </span>evt {
PathEvent::Begin { at } =&gt; { <span class="macro">println!</span>(<span class="string">" - move to {:?}"</span>, at); }
PathEvent::Line { from, to } =&gt; { <span class="macro">println!</span>(<span class="string">" - line {:?} -&gt; {:?}"</span>, from, to); }
PathEvent::End { last, first, close } =&gt; {
<span class="kw">if </span>close {
<span class="macro">println!</span>(<span class="string">" - close {:?} -&gt; {:?}"</span>, last, first);
} <span class="kw">else </span>{
<span class="macro">println!</span>(<span class="string">" - end"</span>);
}
}
<span class="kw">_ </span>=&gt; { <span class="macro">panic!</span>() }
}
}</code></pre></div>
<p>Chaining the provided iterators allow performing some path manipulations lazily
without allocating actual path objects to hold the result of the transformations.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">extern crate </span>lyon_path;
<span class="kw">use </span>lyon_path::iterator::<span class="kw-2">*</span>;
<span class="kw">use </span>lyon_path::math::{point, Angle, Rotation};
<span class="kw">use </span>lyon_path::Path;
<span class="kw">fn </span>main() {
<span class="comment">// In practice it is more common to iterate over Path objects than vectors
// of SVG commands (the former can be constructed from the latter).
</span><span class="kw">let </span><span class="kw-2">mut </span>builder = Path::builder();
builder.begin(point(<span class="number">1.0</span>, <span class="number">1.0</span>));
builder.line_to(point(<span class="number">2.0</span>, <span class="number">1.0</span>));
builder.quadratic_bezier_to(point(<span class="number">2.0</span>, <span class="number">2.0</span>), point(<span class="number">1.0</span>, <span class="number">2.0</span>));
builder.cubic_bezier_to(point(<span class="number">0.0</span>, <span class="number">2.0</span>), point(<span class="number">0.0</span>, <span class="number">0.0</span>), point(<span class="number">1.0</span>, <span class="number">0.0</span>));
builder.end(<span class="bool-val">true</span>);
<span class="kw">let </span>path = builder.build();
<span class="kw">let </span>transform = Rotation::new(Angle::radians(<span class="number">1.0</span>));
<span class="kw">for </span>evt <span class="kw">in </span>path.iter().transformed(<span class="kw-2">&amp;</span>transform).flattened(<span class="number">0.1</span>) {
<span class="comment">// ...
</span>}
}</code></pre></div>
</div></details><h2 id="structs" class="section-header">Structs<a href="#structs" class="anchor">§</a></h2><dl class="item-table"><dt><a class="struct" href="struct.Flattened.html" title="struct cosmic::widget::canvas::path::lyon_path::iterator::Flattened">Flattened</a></dt><dd>An iterator that consumes <code>Event</code> iterator and yields flattened path events (with no curves).</dd><dt><a class="struct" href="struct.FromPolyline.html" title="struct cosmic::widget::canvas::path::lyon_path::iterator::FromPolyline">From<wbr>Polyline</a></dt><dd>An iterator that consumes an iterator of <code>Point</code>s and produces <code>Event</code>s.</dd><dt><a class="struct" href="struct.NoAttributes.html" title="struct cosmic::widget::canvas::path::lyon_path::iterator::NoAttributes">NoAttributes</a></dt><dt><a class="struct" href="struct.Transformed.html" title="struct cosmic::widget::canvas::path::lyon_path::iterator::Transformed">Transformed</a></dt><dd>Applies a 2D transform to a path iterator and yields the resulting path iterator.</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.PathIterator.html" title="trait cosmic::widget::canvas::path::lyon_path::iterator::PathIterator">Path<wbr>Iterator</a></dt><dd>An extension trait for <code>PathEvent</code> iterators.</dd></dl></section></div></main></body></html>