<!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="Source of the Rust file `geom/src/circle.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>circle.rs - source</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../light.css"  id="themeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../../ayu.css" disabled ><script id="default-settings"></script><script src="../../storage.js"></script><script src="../../crates.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../../favicon.svg">
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</pre><pre class="rust">
<span class="kw">use</span> <span class="ident">std::fmt</span>;

<span class="kw">use</span> <span class="ident">anyhow::Result</span>;
<span class="kw">use</span> <span class="ident">serde</span>::{<span class="ident">Deserialize</span>, <span class="ident">Serialize</span>};

<span class="kw">use</span> <span class="kw">crate</span>::{<span class="ident">Angle</span>, <span class="ident">Bounds</span>, <span class="ident">Distance</span>, <span class="ident">Polygon</span>, <span class="ident">Pt2D</span>, <span class="ident">Ring</span>};

<span class="kw">const</span> <span class="ident">TRIANGLES_PER_CIRCLE</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">60</span>;

<span class="doccomment">/// A circle, defined by a center and radius.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Serialize</span>, <span class="ident">Deserialize</span>, <span class="ident">Debug</span>, <span class="ident">Clone</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Circle</span> {
    <span class="kw">pub</span> <span class="ident">center</span>: <span class="ident">Pt2D</span>,
    <span class="kw">pub</span> <span class="ident">radius</span>: <span class="ident">Distance</span>,
}

<span class="kw">impl</span> <span class="ident">Circle</span> {
    <span class="doccomment">/// Creates a circle.</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">center</span>: <span class="ident">Pt2D</span>, <span class="ident">radius</span>: <span class="ident">Distance</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Circle</span> {
        <span class="ident">Circle</span> { <span class="ident">center</span>, <span class="ident">radius</span> }
    }

    <span class="doccomment">/// True if the point is inside the circle.</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">contains_pt</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">pt</span>: <span class="ident">Pt2D</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">bool</span> {
        <span class="comment">// avoid sqrt by squaring radius instead</span>
        (<span class="ident">pt</span>.<span class="ident">x</span>() <span class="op">-</span> <span class="self">self</span>.<span class="ident">center</span>.<span class="ident">x</span>()).<span class="ident">powi</span>(<span class="number">2</span>) <span class="op">+</span> (<span class="ident">pt</span>.<span class="ident">y</span>() <span class="op">-</span> <span class="self">self</span>.<span class="ident">center</span>.<span class="ident">y</span>()).<span class="ident">powi</span>(<span class="number">2</span>)
            <span class="op">&lt;</span> <span class="self">self</span>.<span class="ident">radius</span>.<span class="ident">inner_meters</span>().<span class="ident">powi</span>(<span class="number">2</span>)
    }

    <span class="doccomment">/// Get the boundary containing this circle.</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_bounds</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Bounds</span> {
        <span class="ident">Bounds</span> {
            <span class="ident">min_x</span>: <span class="self">self</span>.<span class="ident">center</span>.<span class="ident">x</span>() <span class="op">-</span> <span class="self">self</span>.<span class="ident">radius</span>.<span class="ident">inner_meters</span>(),
            <span class="ident">max_x</span>: <span class="self">self</span>.<span class="ident">center</span>.<span class="ident">x</span>() <span class="op">+</span> <span class="self">self</span>.<span class="ident">radius</span>.<span class="ident">inner_meters</span>(),
            <span class="ident">min_y</span>: <span class="self">self</span>.<span class="ident">center</span>.<span class="ident">y</span>() <span class="op">-</span> <span class="self">self</span>.<span class="ident">radius</span>.<span class="ident">inner_meters</span>(),
            <span class="ident">max_y</span>: <span class="self">self</span>.<span class="ident">center</span>.<span class="ident">y</span>() <span class="op">+</span> <span class="self">self</span>.<span class="ident">radius</span>.<span class="ident">inner_meters</span>(),
        }
    }

    <span class="doccomment">/// Renders the circle as a polygon.</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">to_polygon</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Polygon</span> {
        <span class="self">self</span>.<span class="ident">to_ring</span>().<span class="ident">into_polygon</span>()
    }

    <span class="doccomment">/// Renders some percent, between [0, 1], of the circle as a polygon. The polygon starts from 0</span>
    <span class="doccomment">/// degrees. Be warned the resulting polygon doesn&#39;t have a ring as its boundary!</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">to_partial_polygon</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">percent_full</span>: <span class="ident">f64</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Polygon</span> {
        <span class="attribute">#![<span class="ident">allow</span>(<span class="ident">clippy::float_cmp</span>)]</span>
        <span class="macro">assert!</span>((<span class="number">0.</span> ..<span class="op">=</span><span class="number">1.</span>).<span class="ident">contains</span>(<span class="kw-2">&amp;</span><span class="ident">percent_full</span>));
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">pts</span> <span class="op">=</span> <span class="macro">vec!</span>[<span class="self">self</span>.<span class="ident">center</span>];
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">indices</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
        <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">TRIANGLES_PER_CIRCLE</span> {
            <span class="ident">pts</span>.<span class="ident">push</span>(<span class="self">self</span>.<span class="ident">center</span>.<span class="ident">project_away</span>(
                <span class="self">self</span>.<span class="ident">radius</span>,
                <span class="ident">Angle::degrees</span>((<span class="ident">i</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">/</span> (<span class="ident">TRIANGLES_PER_CIRCLE</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">*</span> <span class="ident">percent_full</span> <span class="op">*</span> <span class="number">360.0</span>),
            ));
            <span class="ident">indices</span>.<span class="ident">push</span>(<span class="number">0</span>);
            <span class="ident">indices</span>.<span class="ident">push</span>(<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>);
            <span class="kw">if</span> <span class="ident">i</span> <span class="op">!</span><span class="op">=</span> <span class="ident">TRIANGLES_PER_CIRCLE</span> <span class="op">-</span> <span class="number">1</span> {
                <span class="ident">indices</span>.<span class="ident">push</span>(<span class="ident">i</span> <span class="op">+</span> <span class="number">2</span>);
            } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">percent_full</span> <span class="op">=</span><span class="op">=</span> <span class="number">1.0</span> {
                <span class="ident">indices</span>.<span class="ident">push</span>(<span class="number">1</span>);
            } <span class="kw">else</span> {
                <span class="ident">indices</span>.<span class="ident">pop</span>();
                <span class="ident">indices</span>.<span class="ident">pop</span>();
            }
        }
        <span class="ident">Polygon::precomputed</span>(<span class="ident">pts</span>, <span class="ident">indices</span>)
    }

    <span class="doccomment">/// Returns the ring around the circle.</span>
    <span class="kw">fn</span> <span class="ident">to_ring</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Ring</span> {
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">pts</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">Pt2D</span><span class="op">&gt;</span> <span class="op">=</span> (<span class="number">0</span>..<span class="op">=</span><span class="ident">TRIANGLES_PER_CIRCLE</span>)
            .<span class="ident">map</span>(<span class="op">|</span><span class="ident">i</span><span class="op">|</span> {
                <span class="self">self</span>.<span class="ident">center</span>.<span class="ident">project_away</span>(
                    <span class="self">self</span>.<span class="ident">radius</span>,
                    <span class="ident">Angle::degrees</span>((<span class="ident">i</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">/</span> (<span class="ident">TRIANGLES_PER_CIRCLE</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">*</span> <span class="number">360.0</span>),
                )
            })
            .<span class="ident">collect</span>();
        <span class="comment">// With some radii, we get duplicate adjacent points</span>
        <span class="ident">pts</span>.<span class="ident">dedup</span>();
        <span class="ident">Ring::must_new</span>(<span class="ident">pts</span>)
    }

    <span class="doccomment">/// Creates an outline around the circle, strictly contained with the circle&#39;s original radius.</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">to_outline</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">thickness</span>: <span class="ident">Distance</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="prelude-ty">Result</span><span class="op">&lt;</span><span class="ident">Polygon</span><span class="op">&gt;</span> {
        <span class="kw">if</span> <span class="self">self</span>.<span class="ident">radius</span> <span class="op">&lt;</span><span class="op">=</span> <span class="ident">thickness</span> {
            <span class="macro">bail!</span>(
                <span class="string">&quot;Can&#39;t make Circle outline with radius {} and thickness {}&quot;</span>,
                <span class="self">self</span>.<span class="ident">radius</span>,
                <span class="ident">thickness</span>
            );
        }

        <span class="kw">let</span> <span class="ident">bigger</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">to_ring</span>();
        <span class="kw">let</span> <span class="ident">smaller</span> <span class="op">=</span> <span class="ident">Circle::new</span>(<span class="self">self</span>.<span class="ident">center</span>, <span class="self">self</span>.<span class="ident">radius</span> <span class="op">-</span> <span class="ident">thickness</span>).<span class="ident">to_ring</span>();
        <span class="prelude-val">Ok</span>(<span class="ident">Polygon::with_holes</span>(<span class="ident">bigger</span>, <span class="macro">vec!</span>[<span class="ident">smaller</span>]))
    }
}

<span class="kw">impl</span> <span class="ident">fmt::Display</span> <span class="kw">for</span> <span class="ident">Circle</span> {
    <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">fmt::Formatter</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">fmt::Result</span> {
        <span class="macro">write!</span>(<span class="ident">f</span>, <span class="string">&quot;Circle({}, {})&quot;</span>, <span class="self">self</span>.<span class="ident">center</span>, <span class="self">self</span>.<span class="ident">radius</span>)
    }
}
</pre></div>
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