| <!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/animation.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>animation.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="kw">use </span>std::iter::Iterator; |
| <span class="kw">use </span>std::time::Duration; |
| |
| <span class="kw">use </span>num_rational::Ratio; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::RgbaImage; |
| <span class="kw">use </span><span class="kw">crate</span>::error::ImageResult; |
| |
| <span class="doccomment">/// An implementation dependent iterator, reading the frames as requested |
| </span><span class="kw">pub struct </span>Frames<<span class="lifetime">'a</span>> { |
| iterator: Box<<span class="kw">dyn </span>Iterator<Item = ImageResult<Frame>> + <span class="lifetime">'a</span>> |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> Frames<<span class="lifetime">'a</span>> { |
| <span class="doccomment">/// Creates a new `Frames` from an implementation specific iterator. |
| </span><span class="kw">pub fn </span>new(iterator: Box<<span class="kw">dyn </span>Iterator<Item = ImageResult<Frame>> + <span class="lifetime">'a</span>>) -> <span class="self">Self </span>{ |
| Frames { iterator } |
| } |
| |
| <span class="doccomment">/// Steps through the iterator from the current frame until the end and pushes each frame into |
| /// a `Vec`. |
| /// If en error is encountered that error is returned instead. |
| /// |
| /// Note: This is equivalent to `Frames::collect::<ImageResult<Vec<Frame>>>()` |
| </span><span class="kw">pub fn </span>collect_frames(<span class="self">self</span>) -> ImageResult<Vec<Frame>> { |
| <span class="self">self</span>.collect() |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> Iterator <span class="kw">for </span>Frames<<span class="lifetime">'a</span>> { |
| <span class="kw">type </span>Item = ImageResult<Frame>; |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><ImageResult<Frame>> { |
| <span class="self">self</span>.iterator.next() |
| } |
| } |
| |
| <span class="doccomment">/// A single animation frame |
| </span><span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>Frame { |
| <span class="doccomment">/// Delay between the frames in milliseconds |
| </span>delay: Delay, |
| <span class="doccomment">/// x offset |
| </span>left: u32, |
| <span class="doccomment">/// y offset |
| </span>top: u32, |
| buffer: RgbaImage, |
| } |
| |
| <span class="doccomment">/// The delay of a frame relative to the previous one. |
| </span><span class="attribute">#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd)] |
| </span><span class="kw">pub struct </span>Delay { |
| ratio: Ratio<u32>, |
| } |
| |
| <span class="kw">impl </span>Frame { |
| <span class="doccomment">/// Contructs a new frame without any delay. |
| </span><span class="kw">pub fn </span>new(buffer: RgbaImage) -> Frame { |
| Frame { |
| delay: Delay::from_ratio(Ratio::from_integer(<span class="number">0</span>)), |
| left: <span class="number">0</span>, |
| top: <span class="number">0</span>, |
| buffer, |
| } |
| } |
| |
| <span class="doccomment">/// Contructs a new frame |
| </span><span class="kw">pub fn </span>from_parts(buffer: RgbaImage, left: u32, top: u32, delay: Delay) -> Frame { |
| Frame { |
| delay, |
| left, |
| top, |
| buffer, |
| } |
| } |
| |
| <span class="doccomment">/// Delay of this frame |
| </span><span class="kw">pub fn </span>delay(<span class="kw-2">&</span><span class="self">self</span>) -> Delay { |
| <span class="self">self</span>.delay |
| } |
| |
| <span class="doccomment">/// Returns the image buffer |
| </span><span class="kw">pub fn </span>buffer(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>RgbaImage { |
| <span class="kw-2">&</span><span class="self">self</span>.buffer |
| } |
| |
| <span class="doccomment">/// Returns a mutable image buffer |
| </span><span class="kw">pub fn </span>buffer_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>RgbaImage { |
| <span class="kw-2">&mut </span><span class="self">self</span>.buffer |
| } |
| |
| <span class="doccomment">/// Returns the image buffer |
| </span><span class="kw">pub fn </span>into_buffer(<span class="self">self</span>) -> RgbaImage { |
| <span class="self">self</span>.buffer |
| } |
| |
| <span class="doccomment">/// Returns the x offset |
| </span><span class="kw">pub fn </span>left(<span class="kw-2">&</span><span class="self">self</span>) -> u32 { |
| <span class="self">self</span>.left |
| } |
| |
| <span class="doccomment">/// Returns the y offset |
| </span><span class="kw">pub fn </span>top(<span class="kw-2">&</span><span class="self">self</span>) -> u32 { |
| <span class="self">self</span>.top |
| } |
| } |
| |
| <span class="kw">impl </span>Delay { |
| <span class="doccomment">/// Create a delay from a ratio of milliseconds. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use image::Delay; |
| /// let delay_10ms = Delay::from_numer_denom_ms(10, 1); |
| /// ``` |
| </span><span class="kw">pub fn </span>from_numer_denom_ms(numerator: u32, denominator: u32) -> <span class="self">Self </span>{ |
| Delay { ratio: Ratio::new_raw(numerator, denominator) } |
| } |
| |
| <span class="doccomment">/// Convert from a duration, clamped between 0 and an implemented defined maximum. |
| /// |
| /// The maximum is *at least* `i32::MAX` milliseconds. It should be noted that the accuracy of |
| /// the result may be relative and very large delays have a coarse resolution. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::time::Duration; |
| /// use image::Delay; |
| /// |
| /// let duration = Duration::from_millis(20); |
| /// let delay = Delay::from_saturating_duration(duration); |
| /// ``` |
| </span><span class="kw">pub fn </span>from_saturating_duration(duration: Duration) -> <span class="self">Self </span>{ |
| <span class="comment">// A few notes: The largest number we can represent as a ratio is u32::MAX but we can |
| // sometimes represent much smaller numbers. |
| // |
| // We can represent duration as `millis+a/b` (where a < b, b > 0). |
| // We must thus bound b with `b·millis + (b-1) <= u32::MAX` or |
| // > `0 < b <= (u32::MAX + 1)/(millis + 1)` |
| // Corollary: millis <= u32::MAX |
| |
| </span><span class="kw">const </span>MILLIS_BOUND: u128 = u32::max_value() <span class="kw">as </span>u128; |
| |
| <span class="kw">let </span>millis = duration.as_millis().min(MILLIS_BOUND); |
| <span class="kw">let </span>submillis = (duration.as_nanos() % <span class="number">1_000_000</span>) <span class="kw">as </span>u32; |
| |
| <span class="kw">let </span>max_b = <span class="kw">if </span>millis > <span class="number">0 </span>{ |
| ((MILLIS_BOUND + <span class="number">1</span>)/(millis + <span class="number">1</span>)) <span class="kw">as </span>u32 |
| } <span class="kw">else </span>{ |
| MILLIS_BOUND <span class="kw">as </span>u32 |
| }; |
| <span class="kw">let </span>millis = millis <span class="kw">as </span>u32; |
| |
| <span class="kw">let </span>(a, b) = <span class="self">Self</span>::closest_bounded_fraction(max_b, submillis, <span class="number">1_000_000</span>); |
| <span class="self">Self</span>::from_numer_denom_ms(a + b<span class="kw-2">*</span>millis, b) |
| } |
| |
| <span class="doccomment">/// The numerator and denominator of the delay in milliseconds. |
| /// |
| /// This is guaranteed to be an exact conversion if the `Delay` was previously created with the |
| /// `from_numer_denom_ms` constructor. |
| </span><span class="kw">pub fn </span>numer_denom_ms(<span class="self">self</span>) -> (u32, u32) { |
| (<span class="kw-2">*</span><span class="self">self</span>.ratio.numer(), <span class="kw-2">*</span><span class="self">self</span>.ratio.denom()) |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>from_ratio(ratio: Ratio<u32>) -> <span class="self">Self </span>{ |
| Delay { ratio } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>into_ratio(<span class="self">self</span>) -> Ratio<u32> { |
| <span class="self">self</span>.ratio |
| } |
| |
| <span class="doccomment">/// Given some fraction, compute an approximation with denominator bounded. |
| /// |
| /// Note that `denom_bound` bounds nominator and denominator of all intermediate |
| /// approximations and the end result. |
| </span><span class="kw">fn </span>closest_bounded_fraction(denom_bound: u32, nom: u32, denom: u32) -> (u32, u32) { |
| <span class="kw">use </span>std::cmp::Ordering::{<span class="self">self</span>, <span class="kw-2">*</span>}; |
| <span class="macro">assert!</span>(<span class="number">0 </span>< denom); |
| <span class="macro">assert!</span>(<span class="number">0 </span>< denom_bound); |
| <span class="macro">assert!</span>(nom < denom); |
| |
| <span class="comment">// Avoid a few type troubles. All intermediate results are bounded by `denom_bound` which |
| // is in turn bounded by u32::MAX. Representing with u64 allows multiplication of any two |
| // values without fears of overflow. |
| |
| // Compare two fractions whose parts fit into a u32. |
| </span><span class="kw">fn </span>compare_fraction((an, ad): (u64, u64), (bn, bd): (u64, u64)) -> Ordering { |
| (an<span class="kw-2">*</span>bd).cmp(<span class="kw-2">&</span>(bn<span class="kw-2">*</span>ad)) |
| } |
| |
| <span class="comment">// Computes the nominator of the absolute difference between two such fractions. |
| </span><span class="kw">fn </span>abs_diff_nom((an, ad): (u64, u64), (bn, bd): (u64, u64)) -> u64 { |
| <span class="kw">let </span>c0 = an<span class="kw-2">*</span>bd; |
| <span class="kw">let </span>c1 = ad<span class="kw-2">*</span>bn; |
| |
| <span class="kw">let </span>d0 = c0.max(c1); |
| <span class="kw">let </span>d1 = c0.min(c1); |
| d0 - d1 |
| } |
| |
| <span class="kw">let </span>exact = (u64::from(nom), u64::from(denom)); |
| <span class="comment">// The lower bound fraction, numerator and denominator. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>lower = (<span class="number">0u64</span>, <span class="number">1u64</span>); |
| <span class="comment">// The upper bound fraction, numerator and denominator. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>upper = (<span class="number">1u64</span>, <span class="number">1u64</span>); |
| <span class="comment">// The closest approximation for now. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>guess = (u64::from(nom<span class="kw-2">*</span><span class="number">2 </span>> denom), <span class="number">1u64</span>); |
| |
| <span class="comment">// loop invariant: ad, bd <= denom_bound |
| // iterates the Farey sequence. |
| </span><span class="kw">loop </span>{ |
| <span class="comment">// Break if we are done. |
| </span><span class="kw">if </span>compare_fraction(guess, exact) == Equal { |
| <span class="kw">break</span>; |
| } |
| |
| <span class="comment">// Break if next Farey number is out-of-range. |
| </span><span class="kw">if </span>u64::from(denom_bound) - lower.<span class="number">1 </span>< upper.<span class="number">1 </span>{ |
| <span class="kw">break</span>; |
| } |
| |
| <span class="comment">// Next Farey approximation n between a and b |
| </span><span class="kw">let </span>next = (lower.<span class="number">0 </span>+ upper.<span class="number">0</span>, lower.<span class="number">1 </span>+ upper.<span class="number">1</span>); |
| <span class="comment">// if F < n then replace the upper bound, else replace lower. |
| </span><span class="kw">if </span>compare_fraction(exact, next) == Less { |
| upper = next; |
| } <span class="kw">else </span>{ |
| lower = next; |
| } |
| |
| <span class="comment">// Now correct the closest guess. |
| // In other words, if |c - f| > |n - f| then replace it with the new guess. |
| // This favors the guess with smaller denominator on equality. |
| |
| // |g - f| = |g_diff_nom|/(gd*fd); |
| </span><span class="kw">let </span>g_diff_nom = abs_diff_nom(guess, exact); |
| <span class="comment">// |n - f| = |n_diff_nom|/(nd*fd); |
| </span><span class="kw">let </span>n_diff_nom = abs_diff_nom(next, exact); |
| |
| <span class="comment">// The difference |n - f| is smaller than |g - f| if either the integral part of the |
| // fraction |n_diff_nom|/nd is smaller than the one of |g_diff_nom|/gd or if they are |
| // the same but the fractional part is larger. |
| </span><span class="kw">if match </span>(n_diff_nom/next.<span class="number">1</span>).cmp(<span class="kw-2">&</span>(g_diff_nom/guess.<span class="number">1</span>)) { |
| Less => <span class="bool-val">true</span>, |
| Greater => <span class="bool-val">false</span>, |
| <span class="comment">// Note that the nominator for the fractional part is smaller than its denominator |
| // which is smaller than u32 and can't overflow the multiplication with the other |
| // denominator, that is we can compare these fractions by multiplication with the |
| // respective other denominator. |
| </span>Equal => compare_fraction((n_diff_nom%next.<span class="number">1</span>, next.<span class="number">1</span>), (g_diff_nom%guess.<span class="number">1</span>, guess.<span class="number">1</span>)) == Less, |
| } { |
| guess = next; |
| } |
| } |
| |
| (guess.<span class="number">0 </span><span class="kw">as </span>u32, guess.<span class="number">1 </span><span class="kw">as </span>u32) |
| } |
| } |
| |
| <span class="kw">impl </span>From<Delay> <span class="kw">for </span>Duration { |
| <span class="kw">fn </span>from(delay: Delay) -> <span class="self">Self </span>{ |
| <span class="kw">let </span>ratio = delay.into_ratio(); |
| <span class="kw">let </span>ms = ratio.to_integer(); |
| <span class="kw">let </span>rest = ratio.numer() % ratio.denom(); |
| <span class="kw">let </span>nanos = (u64::from(rest) * <span class="number">1_000_000</span>) / u64::from(<span class="kw-2">*</span>ratio.denom()); |
| Duration::from_millis(ms.into()) + Duration::from_nanos(nanos) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use super</span>::{Delay, Duration, Ratio}; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>simple() { |
| <span class="kw">let </span>second = Delay::from_numer_denom_ms(<span class="number">1000</span>, <span class="number">1</span>); |
| <span class="macro">assert_eq!</span>(Duration::from(second), Duration::from_secs(<span class="number">1</span>)); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>fps_30() { |
| <span class="kw">let </span>thirtieth = Delay::from_numer_denom_ms(<span class="number">1000</span>, <span class="number">30</span>); |
| <span class="kw">let </span>duration = Duration::from(thirtieth); |
| <span class="macro">assert_eq!</span>(duration.as_secs(), <span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(duration.subsec_millis(), <span class="number">33</span>); |
| <span class="macro">assert_eq!</span>(duration.subsec_nanos(), <span class="number">33_333_333</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>duration_outlier() { |
| <span class="kw">let </span>oob = Duration::from_secs(<span class="number">0xFFFF_FFFF</span>); |
| <span class="kw">let </span>delay = Delay::from_saturating_duration(oob); |
| <span class="macro">assert_eq!</span>(delay.numer_denom_ms(), (<span class="number">0xFFFF_FFFF</span>, <span class="number">1</span>)); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>duration_approx() { |
| <span class="kw">let </span>oob = Duration::from_millis(<span class="number">0xFFFF_FFFF</span>) + Duration::from_micros(<span class="number">1</span>); |
| <span class="kw">let </span>delay = Delay::from_saturating_duration(oob); |
| <span class="macro">assert_eq!</span>(delay.numer_denom_ms(), (<span class="number">0xFFFF_FFFF</span>, <span class="number">1</span>)); |
| |
| <span class="kw">let </span>inbounds = Duration::from_millis(<span class="number">0xFFFF_FFFF</span>) - Duration::from_micros(<span class="number">1</span>); |
| <span class="kw">let </span>delay = Delay::from_saturating_duration(inbounds); |
| <span class="macro">assert_eq!</span>(delay.numer_denom_ms(), (<span class="number">0xFFFF_FFFF</span>, <span class="number">1</span>)); |
| |
| <span class="kw">let </span>fine = Duration::from_millis(<span class="number">0xFFFF_FFFF</span>/<span class="number">1000</span>) + Duration::from_micros(<span class="number">0xFFFF_FFFF</span>%<span class="number">1000</span>); |
| <span class="kw">let </span>delay = Delay::from_saturating_duration(fine); |
| <span class="comment">// Funnily, 0xFFFF_FFFF is divisble by 5, thus we compare with a `Ratio`. |
| </span><span class="macro">assert_eq!</span>(delay.into_ratio(), Ratio::new(<span class="number">0xFFFF_FFFF</span>, <span class="number">1000</span>)); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>precise() { |
| <span class="comment">// The ratio has only 32 bits in the numerator, too imprecise to get more than 11 digits |
| // correct. But it may be expressed as 1_000_000/3 instead. |
| </span><span class="kw">let </span>exceed = Duration::from_secs(<span class="number">333</span>) + Duration::from_nanos(<span class="number">333_333_333</span>); |
| <span class="kw">let </span>delay = Delay::from_saturating_duration(exceed); |
| <span class="macro">assert_eq!</span>(Duration::from(delay), exceed); |
| } |
| |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>small() { |
| <span class="comment">// Not quite a delay of `1 ms`. |
| </span><span class="kw">let </span>delay = Delay::from_numer_denom_ms(<span class="number">1 </span><< <span class="number">16</span>, (<span class="number">1 </span><< <span class="number">16</span>) + <span class="number">1</span>); |
| <span class="kw">let </span>duration = Duration::from(delay); |
| <span class="macro">assert_eq!</span>(duration.as_millis(), <span class="number">0</span>); |
| <span class="comment">// Not precisely the original but should be smaller than 0. |
| </span><span class="kw">let </span>delay = Delay::from_saturating_duration(duration); |
| <span class="macro">assert_eq!</span>(delay.into_ratio().to_integer(), <span class="number">0</span>); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="image" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |