| <!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 `/root/.cargo/git/checkouts/incubator-teaclave-crates-c8106113f74feefc/ede1f68/image/./src/math/utils.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>utils.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../image/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../image/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="doccomment">//! Shared mathematical utility functions. |
| |
| /// Cut value to be inside given range |
| /// |
| /// ``` |
| /// use image::math::utils; |
| /// |
| /// assert_eq!(utils::clamp(-5, 0, 10), 0); |
| /// assert_eq!(utils::clamp( 6, 0, 10), 6); |
| /// assert_eq!(utils::clamp(15, 0, 10), 10); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| #[deprecated] |
| </span><span class="kw">pub fn </span>clamp<N>(a: N, min: N, max: N) -> N |
| <span class="kw">where |
| </span>N: PartialOrd, |
| { |
| <span class="kw">if </span>a < min { |
| <span class="kw">return </span>min; |
| } |
| <span class="kw">if </span>a > max { |
| <span class="kw">return </span>max; |
| } |
| a |
| } |
| |
| <span class="doccomment">/// Calculates the width and height an image should be resized to. |
| /// This preserves aspect ratio, and based on the `fill` parameter |
| /// will either fill the dimensions to fit inside the smaller constraint |
| /// (will overflow the specified bounds on one axis to preserve |
| /// aspect ratio), or will shrink so that both dimensions are |
| /// completely contained with in the given `width` and `height`, |
| /// with empty space on one axis. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>resize_dimensions(width: u32, height: u32, nwidth: u32, nheight: u32, fill: bool) -> (u32, u32) { |
| <span class="kw">let </span>ratio = u64::from(width) * u64::from(nheight); |
| <span class="kw">let </span>nratio = u64::from(nwidth) * u64::from(height); |
| |
| <span class="kw">let </span>use_width = <span class="kw">if </span>fill { |
| nratio > ratio |
| } <span class="kw">else </span>{ |
| nratio <= ratio |
| }; |
| <span class="kw">let </span>intermediate = <span class="kw">if </span>use_width { |
| u64::from(height) * u64::from(nwidth) / u64::from(width) |
| } <span class="kw">else </span>{ |
| u64::from(width) * u64::from(nheight) / u64::from(height) |
| }; |
| <span class="kw">let </span>intermediate = std::cmp::max(<span class="number">1</span>, intermediate); |
| <span class="kw">if </span>use_width { |
| <span class="kw">if </span>intermediate <= u64::from(::std::u32::MAX) { |
| (nwidth, intermediate <span class="kw">as </span>u32) |
| } <span class="kw">else </span>{ |
| ( |
| (u64::from(nwidth) * u64::from(::std::u32::MAX) / intermediate) <span class="kw">as </span>u32, |
| ::std::u32::MAX, |
| ) |
| } |
| } <span class="kw">else if </span>intermediate <= u64::from(::std::u32::MAX) { |
| (intermediate <span class="kw">as </span>u32, nheight) |
| } <span class="kw">else </span>{ |
| ( |
| ::std::u32::MAX, |
| (u64::from(nheight) * u64::from(::std::u32::MAX) / intermediate) <span class="kw">as </span>u32, |
| ) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>test { |
| <span class="macro">quickcheck! </span>{ |
| <span class="kw">fn </span>resize_bounds_correctly_width(old_w: u32, new_w: u32) -> bool { |
| <span class="kw">if </span>old_w == <span class="number">0 </span>|| new_w == <span class="number">0 </span>{ <span class="kw">return </span><span class="bool-val">true</span>; } |
| <span class="kw">let </span>result = <span class="kw">super</span>::resize_dimensions(old_w, <span class="number">400</span>, new_w, ::std::u32::MAX, <span class="bool-val">false</span>); |
| result.<span class="number">0 </span>== new_w && result.<span class="number">1 </span>== (<span class="number">400 </span><span class="kw">as </span>f64 * new_w <span class="kw">as </span>f64 / old_w <span class="kw">as </span>f64) <span class="kw">as </span>u32 |
| } |
| } |
| |
| <span class="macro">quickcheck! </span>{ |
| <span class="kw">fn </span>resize_bounds_correctly_height(old_h: u32, new_h: u32) -> bool { |
| <span class="kw">if </span>old_h == <span class="number">0 </span>|| new_h == <span class="number">0 </span>{ <span class="kw">return </span><span class="bool-val">true</span>; } |
| <span class="kw">let </span>result = <span class="kw">super</span>::resize_dimensions(<span class="number">400</span>, old_h, ::std::u32::MAX, new_h, <span class="bool-val">false</span>); |
| result.<span class="number">1 </span>== new_h && result.<span class="number">0 </span>== (<span class="number">400 </span><span class="kw">as </span>f64 * new_h <span class="kw">as </span>f64 / old_h <span class="kw">as </span>f64) <span class="kw">as </span>u32 |
| } |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>resize_handles_fill() { |
| <span class="kw">let </span>result = <span class="kw">super</span>::resize_dimensions(<span class="number">100</span>, <span class="number">200</span>, <span class="number">200</span>, <span class="number">500</span>, <span class="bool-val">true</span>); |
| <span class="macro">assert!</span>(result.<span class="number">0 </span>== <span class="number">250</span>); |
| <span class="macro">assert!</span>(result.<span class="number">1 </span>== <span class="number">500</span>); |
| |
| <span class="kw">let </span>result = <span class="kw">super</span>::resize_dimensions(<span class="number">200</span>, <span class="number">100</span>, <span class="number">500</span>, <span class="number">200</span>, <span class="bool-val">true</span>); |
| <span class="macro">assert!</span>(result.<span class="number">0 </span>== <span class="number">500</span>); |
| <span class="macro">assert!</span>(result.<span class="number">1 </span>== <span class="number">250</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>resize_never_rounds_to_zero() { |
| <span class="kw">let </span>result = <span class="kw">super</span>::resize_dimensions(<span class="number">1</span>, <span class="number">150</span>, <span class="number">128</span>, <span class="number">128</span>, <span class="bool-val">false</span>); |
| <span class="macro">assert!</span>(result.<span class="number">0 </span>> <span class="number">0</span>); |
| <span class="macro">assert!</span>(result.<span class="number">1 </span>> <span class="number">0</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>resize_handles_overflow() { |
| <span class="kw">let </span>result = <span class="kw">super</span>::resize_dimensions(<span class="number">100</span>, ::std::u32::MAX, <span class="number">200</span>, ::std::u32::MAX, <span class="bool-val">true</span>); |
| <span class="macro">assert!</span>(result.<span class="number">0 </span>== <span class="number">100</span>); |
| <span class="macro">assert!</span>(result.<span class="number">1 </span>== ::std::u32::MAX); |
| |
| <span class="kw">let </span>result = <span class="kw">super</span>::resize_dimensions(::std::u32::MAX, <span class="number">100</span>, ::std::u32::MAX, <span class="number">200</span>, <span class="bool-val">true</span>); |
| <span class="macro">assert!</span>(result.<span class="number">0 </span>== ::std::u32::MAX); |
| <span class="macro">assert!</span>(result.<span class="number">1 </span>== <span class="number">100</span>); |
| } |
| } |
| </code></pre></div> |
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