| <!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/registry/src/github.com-1ecc6299db9ec823/jpeg-decoder-0.1.22/src/upsampler.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>upsampler.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="../../jpeg_decoder/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="../../jpeg_decoder/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>error::{Error, <span class="prelude-ty">Result</span>, UnsupportedFeature}; |
| <span class="kw">use </span>parser::Component; |
| |
| <span class="kw">pub struct </span>Upsampler { |
| components: Vec<UpsamplerComponent>, |
| line_buffer_size: usize |
| } |
| |
| <span class="kw">struct </span>UpsamplerComponent { |
| upsampler: Box<<span class="kw">dyn </span>Upsample + Sync>, |
| width: usize, |
| height: usize, |
| row_stride: usize, |
| } |
| |
| <span class="kw">impl </span>Upsampler { |
| <span class="kw">pub fn </span>new(components: <span class="kw-2">&</span>[Component], output_width: u16, output_height: u16) -> <span class="prelude-ty">Result</span><Upsampler> { |
| <span class="kw">let </span>h_max = components.iter().map(|c| c.horizontal_sampling_factor).max().unwrap(); |
| <span class="kw">let </span>v_max = components.iter().map(|c| c.vertical_sampling_factor).max().unwrap(); |
| <span class="kw">let </span><span class="kw-2">mut </span>upsampler_components = Vec::with_capacity(components.len()); |
| |
| <span class="kw">for </span>component <span class="kw">in </span>components { |
| <span class="kw">let </span>upsampler = choose_upsampler((component.horizontal_sampling_factor, |
| component.vertical_sampling_factor), |
| (h_max, v_max), |
| output_width, |
| output_height)<span class="question-mark">?</span>; |
| upsampler_components.push(UpsamplerComponent { |
| upsampler: upsampler, |
| width: component.size.width <span class="kw">as </span>usize, |
| height: component.size.height <span class="kw">as </span>usize, |
| row_stride: component.block_size.width <span class="kw">as </span>usize * component.dct_scale, |
| }); |
| } |
| |
| <span class="kw">let </span>buffer_size = components.iter().map(|c| c.size.width).max().unwrap() <span class="kw">as </span>usize * h_max <span class="kw">as </span>usize; |
| |
| <span class="prelude-val">Ok</span>(Upsampler { |
| components: upsampler_components, |
| line_buffer_size: buffer_size |
| }) |
| } |
| |
| <span class="kw">pub fn </span>upsample_and_interleave_row(<span class="kw-2">&</span><span class="self">self</span>, component_data: <span class="kw-2">&</span>[Vec<u8>], row: usize, output_width: usize, output: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span>component_count = component_data.len(); |
| <span class="kw">let </span><span class="kw-2">mut </span>line_buffer = <span class="macro">vec!</span>[<span class="number">0u8</span>; <span class="self">self</span>.line_buffer_size]; |
| |
| <span class="macro">debug_assert_eq!</span>(component_count, <span class="self">self</span>.components.len()); |
| |
| <span class="kw">for </span>(i, component) <span class="kw">in </span><span class="self">self</span>.components.iter().enumerate() { |
| component.upsampler.upsample_row(<span class="kw-2">&</span>component_data[i], |
| component.width, |
| component.height, |
| component.row_stride, |
| row, |
| output_width, |
| <span class="kw-2">&mut </span>line_buffer); |
| <span class="kw">for </span>x <span class="kw">in </span><span class="number">0 </span>.. output_width { |
| output[x * component_count + i] = line_buffer[x]; |
| } |
| } |
| } |
| } |
| |
| <span class="kw">struct </span>UpsamplerH1V1; |
| <span class="kw">struct </span>UpsamplerH2V1; |
| <span class="kw">struct </span>UpsamplerH1V2; |
| <span class="kw">struct </span>UpsamplerH2V2; |
| |
| <span class="kw">struct </span>UpsamplerGeneric { |
| horizontal_scaling_factor: u8, |
| vertical_scaling_factor: u8 |
| } |
| |
| <span class="kw">fn </span>choose_upsampler(sampling_factors: (u8, u8), |
| max_sampling_factors: (u8, u8), |
| output_width: u16, |
| output_height: u16) -> <span class="prelude-ty">Result</span><Box<<span class="kw">dyn </span>Upsample + Sync>> { |
| <span class="kw">let </span>h1 = sampling_factors.<span class="number">0 </span>== max_sampling_factors.<span class="number">0 </span>|| output_width == <span class="number">1</span>; |
| <span class="kw">let </span>v1 = sampling_factors.<span class="number">1 </span>== max_sampling_factors.<span class="number">1 </span>|| output_height == <span class="number">1</span>; |
| <span class="kw">let </span>h2 = sampling_factors.<span class="number">0 </span>* <span class="number">2 </span>== max_sampling_factors.<span class="number">0</span>; |
| <span class="kw">let </span>v2 = sampling_factors.<span class="number">1 </span>* <span class="number">2 </span>== max_sampling_factors.<span class="number">1</span>; |
| |
| <span class="kw">if </span>h1 && v1 { |
| <span class="prelude-val">Ok</span>(Box::new(UpsamplerH1V1)) |
| } |
| <span class="kw">else if </span>h2 && v1 { |
| <span class="prelude-val">Ok</span>(Box::new(UpsamplerH2V1)) |
| } |
| <span class="kw">else if </span>h1 && v2 { |
| <span class="prelude-val">Ok</span>(Box::new(UpsamplerH1V2)) |
| } |
| <span class="kw">else if </span>h2 && v2 { |
| <span class="prelude-val">Ok</span>(Box::new(UpsamplerH2V2)) |
| } |
| <span class="kw">else </span>{ |
| <span class="kw">if </span>max_sampling_factors.<span class="number">0 </span>% sampling_factors.<span class="number">0 </span>!= <span class="number">0 </span>|| max_sampling_factors.<span class="number">1 </span>% sampling_factors.<span class="number">1 </span>!= <span class="number">0 </span>{ |
| <span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::NonIntegerSubsamplingRatio)) |
| } |
| <span class="kw">else </span>{ |
| <span class="prelude-val">Ok</span>(Box::new(UpsamplerGeneric { |
| horizontal_scaling_factor: max_sampling_factors.<span class="number">0 </span>/ sampling_factors.<span class="number">0</span>, |
| vertical_scaling_factor: max_sampling_factors.<span class="number">1 </span>/ sampling_factors.<span class="number">1 |
| </span>})) |
| } |
| } |
| } |
| |
| <span class="kw">trait </span>Upsample { |
| <span class="kw">fn </span>upsample_row(<span class="kw-2">&</span><span class="self">self</span>, |
| input: <span class="kw-2">&</span>[u8], |
| input_width: usize, |
| input_height: usize, |
| row_stride: usize, |
| row: usize, |
| output_width: usize, |
| output: <span class="kw-2">&mut </span>[u8]); |
| } |
| |
| <span class="kw">impl </span>Upsample <span class="kw">for </span>UpsamplerH1V1 { |
| <span class="kw">fn </span>upsample_row(<span class="kw-2">&</span><span class="self">self</span>, |
| input: <span class="kw-2">&</span>[u8], |
| _input_width: usize, |
| _input_height: usize, |
| row_stride: usize, |
| row: usize, |
| output_width: usize, |
| output: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span>input = <span class="kw-2">&</span>input[row * row_stride ..]; |
| |
| output[..output_width].copy_from_slice(<span class="kw-2">&</span>input[..output_width]); |
| } |
| } |
| |
| <span class="kw">impl </span>Upsample <span class="kw">for </span>UpsamplerH2V1 { |
| <span class="kw">fn </span>upsample_row(<span class="kw-2">&</span><span class="self">self</span>, |
| input: <span class="kw-2">&</span>[u8], |
| input_width: usize, |
| _input_height: usize, |
| row_stride: usize, |
| row: usize, |
| _output_width: usize, |
| output: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span>input = <span class="kw-2">&</span>input[row * row_stride ..]; |
| |
| <span class="kw">if </span>input_width == <span class="number">1 </span>{ |
| output[<span class="number">0</span>] = input[<span class="number">0</span>]; |
| output[<span class="number">1</span>] = input[<span class="number">0</span>]; |
| <span class="kw">return</span>; |
| } |
| |
| output[<span class="number">0</span>] = input[<span class="number">0</span>]; |
| output[<span class="number">1</span>] = ((input[<span class="number">0</span>] <span class="kw">as </span>u32 * <span class="number">3 </span>+ input[<span class="number">1</span>] <span class="kw">as </span>u32 + <span class="number">2</span>) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">1 </span>.. input_width - <span class="number">1 </span>{ |
| <span class="kw">let </span>sample = <span class="number">3 </span>* input[i] <span class="kw">as </span>u32 + <span class="number">2</span>; |
| output[i * <span class="number">2</span>] = ((sample + input[i - <span class="number">1</span>] <span class="kw">as </span>u32) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| output[i * <span class="number">2 </span>+ <span class="number">1</span>] = ((sample + input[i + <span class="number">1</span>] <span class="kw">as </span>u32) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| } |
| |
| output[(input_width - <span class="number">1</span>) * <span class="number">2</span>] = ((input[input_width - <span class="number">1</span>] <span class="kw">as </span>u32 * <span class="number">3 </span>+ input[input_width - <span class="number">2</span>] <span class="kw">as </span>u32 + <span class="number">2</span>) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| output[(input_width - <span class="number">1</span>) * <span class="number">2 </span>+ <span class="number">1</span>] = input[input_width - <span class="number">1</span>]; |
| } |
| } |
| |
| <span class="kw">impl </span>Upsample <span class="kw">for </span>UpsamplerH1V2 { |
| <span class="kw">fn </span>upsample_row(<span class="kw-2">&</span><span class="self">self</span>, |
| input: <span class="kw-2">&</span>[u8], |
| _input_width: usize, |
| input_height: usize, |
| row_stride: usize, |
| row: usize, |
| output_width: usize, |
| output: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span>row_near = row <span class="kw">as </span>f32 / <span class="number">2.0</span>; |
| <span class="comment">// If row_near's fractional is 0.0 we want row_far to be the previous row and if it's 0.5 we |
| // want it to be the next row. |
| </span><span class="kw">let </span>row_far = (row_near + row_near.fract() * <span class="number">3.0 </span>- <span class="number">0.25</span>).min((input_height - <span class="number">1</span>) <span class="kw">as </span>f32); |
| |
| <span class="kw">let </span>input_near = <span class="kw-2">&</span>input[row_near <span class="kw">as </span>usize * row_stride ..]; |
| <span class="kw">let </span>input_far = <span class="kw-2">&</span>input[row_far <span class="kw">as </span>usize * row_stride ..]; |
| |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">0 </span>.. output_width { |
| output[i] = ((<span class="number">3 </span>* input_near[i] <span class="kw">as </span>u32 + input_far[i] <span class="kw">as </span>u32 + <span class="number">2</span>) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>Upsample <span class="kw">for </span>UpsamplerH2V2 { |
| <span class="kw">fn </span>upsample_row(<span class="kw-2">&</span><span class="self">self</span>, |
| input: <span class="kw-2">&</span>[u8], |
| input_width: usize, |
| input_height: usize, |
| row_stride: usize, |
| row: usize, |
| _output_width: usize, |
| output: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span>row_near = row <span class="kw">as </span>f32 / <span class="number">2.0</span>; |
| <span class="comment">// If row_near's fractional is 0.0 we want row_far to be the previous row and if it's 0.5 we |
| // want it to be the next row. |
| </span><span class="kw">let </span>row_far = (row_near + row_near.fract() * <span class="number">3.0 </span>- <span class="number">0.25</span>).min((input_height - <span class="number">1</span>) <span class="kw">as </span>f32); |
| |
| <span class="kw">let </span>input_near = <span class="kw-2">&</span>input[row_near <span class="kw">as </span>usize * row_stride ..]; |
| <span class="kw">let </span>input_far = <span class="kw-2">&</span>input[row_far <span class="kw">as </span>usize * row_stride ..]; |
| |
| <span class="kw">if </span>input_width == <span class="number">1 </span>{ |
| <span class="kw">let </span>value = ((<span class="number">3 </span>* input_near[<span class="number">0</span>] <span class="kw">as </span>u32 + input_far[<span class="number">0</span>] <span class="kw">as </span>u32 + <span class="number">2</span>) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| output[<span class="number">0</span>] = value; |
| output[<span class="number">1</span>] = value; |
| <span class="kw">return</span>; |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>t1 = <span class="number">3 </span>* input_near[<span class="number">0</span>] <span class="kw">as </span>u32 + input_far[<span class="number">0</span>] <span class="kw">as </span>u32; |
| output[<span class="number">0</span>] = ((t1 + <span class="number">2</span>) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">1 </span>.. input_width { |
| <span class="kw">let </span>t0 = t1; |
| t1 = <span class="number">3 </span>* input_near[i] <span class="kw">as </span>u32 + input_far[i] <span class="kw">as </span>u32; |
| |
| output[i * <span class="number">2 </span>- <span class="number">1</span>] = ((<span class="number">3 </span>* t0 + t1 + <span class="number">8</span>) >> <span class="number">4</span>) <span class="kw">as </span>u8; |
| output[i * <span class="number">2</span>] = ((<span class="number">3 </span>* t1 + t0 + <span class="number">8</span>) >> <span class="number">4</span>) <span class="kw">as </span>u8; |
| } |
| |
| output[input_width * <span class="number">2 </span>- <span class="number">1</span>] = ((t1 + <span class="number">2</span>) >> <span class="number">2</span>) <span class="kw">as </span>u8; |
| } |
| } |
| |
| <span class="kw">impl </span>Upsample <span class="kw">for </span>UpsamplerGeneric { |
| <span class="comment">// Uses nearest neighbor sampling |
| </span><span class="kw">fn </span>upsample_row(<span class="kw-2">&</span><span class="self">self</span>, |
| input: <span class="kw-2">&</span>[u8], |
| input_width: usize, |
| _input_height: usize, |
| row_stride: usize, |
| row: usize, |
| _output_width: usize, |
| output: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span><span class="kw-2">mut </span>index = <span class="number">0</span>; |
| <span class="kw">let </span>start = (row / <span class="self">self</span>.vertical_scaling_factor <span class="kw">as </span>usize) * row_stride; |
| <span class="kw">let </span>input = <span class="kw-2">&</span>input[start..(start + input_width)]; |
| <span class="kw">for </span>val <span class="kw">in </span>input { |
| <span class="kw">for _ in </span><span class="number">0</span>..<span class="self">self</span>.horizontal_scaling_factor { |
| output[index] = <span class="kw-2">*</span>val; |
| index += <span class="number">1</span>; |
| } |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="jpeg_decoder" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
