<!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 to the Rust file `/home/mrh/.cargo/registry/src/github.com-1ecc6299db9ec823/png-0.14.1/src/encoder.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>encoder.rs.html -- 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="../../dark.css"><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><script src="../../storage.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="shortcut icon" href="../../favicon.ico"><style type="text/css">#crate-search{background-image:url("../../down-arrow.svg");}</style></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../png/index.html'><div class='logo-container'><img src='../../rust-logo.png' alt='logo'></div></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../../settings.html"><img src="../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span>
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</pre><div class="example-wrap"><pre class="rust ">
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">deflate</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">borrow</span>::<span class="ident">Cow</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">error</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">fmt</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>::{<span class="self">self</span>, <span class="ident">Write</span>};
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">mem</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">result</span>;
<span class="kw">use</span> <span class="ident">chunk</span>;
<span class="kw">use</span> <span class="ident">crc</span>::<span class="ident">Crc32</span>;
<span class="kw">use</span> <span class="ident">common</span>::{<span class="ident">Info</span>, <span class="ident">ColorType</span>, <span class="ident">BitDepth</span>, <span class="ident">Compression</span>};
<span class="kw">use</span> <span class="ident">filter</span>::{<span class="ident">FilterType</span>, <span class="ident">filter</span>};
<span class="kw">use</span> <span class="ident">traits</span>::{<span class="ident">WriteBytesExt</span>, <span class="ident">HasParameters</span>, <span class="ident">Parameter</span>};
<span class="kw">pub</span> <span class="kw">type</span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="op">=</span> <span class="ident">result</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">EncodingError</span><span class="op">></span>;
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">EncodingError</span> {
<span class="ident">IoError</span>(<span class="ident">io</span>::<span class="ident">Error</span>),
<span class="ident">Format</span>(<span class="ident">Cow</span><span class="op"><</span><span class="lifetime">'static</span>, <span class="ident">str</span><span class="op">></span>),
}
<span class="kw">impl</span> <span class="ident">error</span>::<span class="ident">Error</span> <span class="kw">for</span> <span class="ident">EncodingError</span> {
<span class="kw">fn</span> <span class="ident">description</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">str</span> {
<span class="kw">use</span> <span class="self">self</span>::<span class="ident">EncodingError</span>::<span class="kw-2">*</span>;
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">IoError</span>(<span class="kw-2">ref</span> <span class="ident">err</span>) <span class="op">=</span><span class="op">></span> <span class="ident">err</span>.<span class="ident">description</span>(),
<span class="ident">Format</span>(<span class="kw-2">ref</span> <span class="ident">desc</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">desc</span>,
}
}
}
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Display</span> <span class="kw">for</span> <span class="ident">EncodingError</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">fmt</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-</span><span class="op">></span> <span class="ident">result</span>::<span class="prelude-ty">Result</span><span class="op"><</span>(), <span class="ident">fmt</span>::<span class="ident">Error</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">fmt</span>, <span class="string">"{}"</span>, (<span class="self">self</span> <span class="kw">as</span> <span class="kw-2">&</span><span class="ident">error</span>::<span class="ident">Error</span>).<span class="ident">description</span>())
}
}
<span class="kw">impl</span> <span class="ident">From</span><span class="op"><</span><span class="ident">io</span>::<span class="ident">Error</span><span class="op">></span> <span class="kw">for</span> <span class="ident">EncodingError</span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">err</span>: <span class="ident">io</span>::<span class="ident">Error</span>) <span class="op">-</span><span class="op">></span> <span class="ident">EncodingError</span> {
<span class="ident">EncodingError</span>::<span class="ident">IoError</span>(<span class="ident">err</span>)
}
}
<span class="kw">impl</span> <span class="ident">From</span><span class="op"><</span><span class="ident">EncodingError</span><span class="op">></span> <span class="kw">for</span> <span class="ident">io</span>::<span class="ident">Error</span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">err</span>: <span class="ident">EncodingError</span>) <span class="op">-</span><span class="op">></span> <span class="ident">io</span>::<span class="ident">Error</span> {
<span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">io</span>::<span class="ident">ErrorKind</span>::<span class="ident">Other</span>, (<span class="kw-2">&</span><span class="ident">err</span> <span class="kw">as</span> <span class="kw-2">&</span><span class="ident">error</span>::<span class="ident">Error</span>).<span class="ident">description</span>())
}
}
<span class="doccomment">/// PNG Encoder</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> {
<span class="ident">w</span>: <span class="ident">W</span>,
<span class="ident">info</span>: <span class="ident">Info</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> {
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">w</span>: <span class="ident">W</span>, <span class="ident">width</span>: <span class="ident">u32</span>, <span class="ident">height</span>: <span class="ident">u32</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">info</span> <span class="op">=</span> <span class="ident">Info</span>::<span class="ident">default</span>();
<span class="ident">info</span>.<span class="ident">width</span> <span class="op">=</span> <span class="ident">width</span>;
<span class="ident">info</span>.<span class="ident">height</span> <span class="op">=</span> <span class="ident">height</span>;
<span class="ident">Encoder</span> { <span class="ident">w</span>: <span class="ident">w</span>, <span class="ident">info</span>: <span class="ident">info</span> }
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">write_header</span>(<span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Writer</span><span class="op"><</span><span class="ident">W</span><span class="op">></span><span class="op">></span> {
<span class="ident">Writer</span>::<span class="ident">new</span>(<span class="self">self</span>.<span class="ident">w</span>, <span class="self">self</span>.<span class="ident">info</span>).<span class="ident">init</span>()
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">HasParameters</span> <span class="kw">for</span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> {}
<span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Parameter</span><span class="op"><</span><span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span><span class="op">></span> <span class="kw">for</span> <span class="ident">ColorType</span> {
<span class="kw">fn</span> <span class="ident">set_param</span>(<span class="self">self</span>, <span class="ident">this</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>) {
<span class="ident">this</span>.<span class="ident">info</span>.<span class="ident">color_type</span> <span class="op">=</span> <span class="self">self</span>
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Parameter</span><span class="op"><</span><span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span><span class="op">></span> <span class="kw">for</span> <span class="ident">BitDepth</span> {
<span class="kw">fn</span> <span class="ident">set_param</span>(<span class="self">self</span>, <span class="ident">this</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>) {
<span class="ident">this</span>.<span class="ident">info</span>.<span class="ident">bit_depth</span> <span class="op">=</span> <span class="self">self</span>
}
}
<span class="doccomment">/// Set compression param for a ```Compression``` or any type that can transform </span>
<span class="doccomment">/// into a ```Compression```, notably ```deflate::Compression``` and </span>
<span class="doccomment">/// ```deflate::CompressionOptions``` which "just work".</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span>, <span class="ident">C</span>: <span class="ident">Into</span><span class="op"><</span><span class="ident">Compression</span><span class="op">></span><span class="op">></span> <span class="ident">Parameter</span><span class="op"><</span><span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span><span class="op">></span> <span class="kw">for</span> <span class="ident">C</span> {
<span class="kw">fn</span> <span class="ident">set_param</span>(<span class="self">self</span>, <span class="ident">this</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>) {
<span class="ident">this</span>.<span class="ident">info</span>.<span class="ident">compression</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">into</span>()
}
}
<span class="kw">impl</span> <span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Parameter</span><span class="op"><</span><span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span><span class="op">></span> <span class="kw">for</span> <span class="ident">FilterType</span> {
<span class="kw">fn</span> <span class="ident">set_param</span>(<span class="self">self</span>, <span class="ident">this</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Encoder</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>) {
<span class="ident">this</span>.<span class="ident">info</span>.<span class="ident">filter</span> <span class="op">=</span> <span class="self">self</span>
}
}
<span class="doccomment">/// PNG writer</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Writer</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> {
<span class="ident">w</span>: <span class="ident">W</span>,
<span class="ident">info</span>: <span class="ident">Info</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Writer</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">w</span>: <span class="ident">W</span>, <span class="ident">info</span>: <span class="ident">Info</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Writer</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">w</span> <span class="op">=</span> <span class="ident">Writer</span> { <span class="ident">w</span>: <span class="ident">w</span>, <span class="ident">info</span>: <span class="ident">info</span> };
<span class="ident">w</span>
}
<span class="kw">fn</span> <span class="ident">init</span>(<span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="self">Self</span><span class="op">></span> {
<span class="macro">try</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span>[<span class="number">137</span>, <span class="number">80</span>, <span class="number">78</span>, <span class="number">71</span>, <span class="number">13</span>, <span class="number">10</span>, <span class="number">26</span>, <span class="number">10</span>]));
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">data</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">13</span>];
<span class="macro">try</span><span class="macro">!</span>((<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">data</span>[..]).<span class="ident">write_be</span>(<span class="self">self</span>.<span class="ident">info</span>.<span class="ident">width</span>));
<span class="macro">try</span><span class="macro">!</span>((<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">data</span>[<span class="number">4</span>..]).<span class="ident">write_be</span>(<span class="self">self</span>.<span class="ident">info</span>.<span class="ident">height</span>));
<span class="ident">data</span>[<span class="number">8</span>] <span class="op">=</span> <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">bit_depth</span> <span class="kw">as</span> <span class="ident">u8</span>;
<span class="ident">data</span>[<span class="number">9</span>] <span class="op">=</span> <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">color_type</span> <span class="kw">as</span> <span class="ident">u8</span>;
<span class="ident">data</span>[<span class="number">12</span>] <span class="op">=</span> <span class="kw">if</span> <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">interlaced</span> { <span class="number">1</span> } <span class="kw">else</span> { <span class="number">0</span> };
<span class="macro">try</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">write_chunk</span>(<span class="ident">chunk</span>::<span class="ident">IHDR</span>, <span class="kw-2">&</span><span class="ident">data</span>));
<span class="prelude-val">Ok</span>(<span class="self">self</span>)
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">write_chunk</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">name</span>: [<span class="ident">u8</span>; <span class="number">4</span>], <span class="ident">data</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> {
<span class="macro">try</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">write_be</span>(<span class="ident">data</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">u32</span>));
<span class="macro">try</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span><span class="ident">name</span>));
<span class="macro">try</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">write_all</span>(<span class="ident">data</span>));
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">crc</span> <span class="op">=</span> <span class="ident">Crc32</span>::<span class="ident">new</span>();
<span class="ident">crc</span>.<span class="ident">update</span>(<span class="kw-2">&</span><span class="ident">name</span>);
<span class="ident">crc</span>.<span class="ident">update</span>(<span class="ident">data</span>);
<span class="macro">try</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">write_be</span>(<span class="ident">crc</span>.<span class="ident">checksum</span>()));
<span class="prelude-val">Ok</span>(())
}
<span class="doccomment">/// Writes the image data.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">write_image_data</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">data</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> {
<span class="kw">let</span> <span class="ident">bpp</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">bytes_per_pixel</span>();
<span class="kw">let</span> <span class="ident">in_len</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">raw_row_length</span>() <span class="op">-</span> <span class="number">1</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">prev</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0</span>; <span class="ident">in_len</span>];
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">current</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0</span>; <span class="ident">in_len</span>];
<span class="kw">let</span> <span class="ident">data_size</span> <span class="op">=</span> <span class="ident">in_len</span> <span class="op">*</span> <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">height</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">if</span> <span class="ident">data_size</span> <span class="op">!</span><span class="op">=</span> <span class="ident">data</span>.<span class="ident">len</span>() {
<span class="kw">let</span> <span class="ident">message</span> <span class="op">=</span> <span class="macro">format</span><span class="macro">!</span>(<span class="string">"wrong data size, expected {} got {}"</span>, <span class="ident">data_size</span>, <span class="ident">data</span>.<span class="ident">len</span>());
<span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">EncodingError</span>::<span class="ident">Format</span>(<span class="ident">message</span>.<span class="ident">into</span>()));
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">zlib</span> <span class="op">=</span> <span class="ident">deflate</span>::<span class="ident">write</span>::<span class="ident">ZlibEncoder</span>::<span class="ident">new</span>(<span class="ident">Vec</span>::<span class="ident">new</span>(), <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">compression</span>.<span class="ident">clone</span>());
<span class="kw">let</span> <span class="ident">filter_method</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">info</span>.<span class="ident">filter</span>;
<span class="kw">for</span> <span class="ident">line</span> <span class="kw">in</span> <span class="ident">data</span>.<span class="ident">chunks</span>(<span class="ident">in_len</span>) {
<span class="ident">current</span>.<span class="ident">copy_from_slice</span>(<span class="kw-2">&</span><span class="ident">line</span>);
<span class="macro">try</span><span class="macro">!</span>(<span class="ident">zlib</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span>[<span class="ident">filter_method</span> <span class="kw">as</span> <span class="ident">u8</span>]));
<span class="ident">filter</span>(<span class="ident">filter_method</span>, <span class="ident">bpp</span>, <span class="kw-2">&</span><span class="ident">prev</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">current</span>);
<span class="macro">try</span><span class="macro">!</span>(<span class="ident">zlib</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span><span class="ident">current</span>));
<span class="ident">mem</span>::<span class="ident">swap</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">prev</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">current</span>);
}
<span class="self">self</span>.<span class="ident">write_chunk</span>(<span class="ident">chunk</span>::<span class="ident">IDAT</span>, <span class="kw-2">&</span><span class="macro">try</span><span class="macro">!</span>(<span class="ident">zlib</span>.<span class="ident">finish</span>()))
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Writer</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">let</span> <span class="kw">_</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">write_chunk</span>(<span class="ident">chunk</span>::<span class="ident">IEND</span>, <span class="kw-2">&</span>[]);
}
}
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span>
<span class="kw">mod</span> <span class="ident">tests</span> {
<span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>;
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">rand</span>;
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">glob</span>;
<span class="kw">use</span> <span class="self">self</span>::<span class="ident">rand</span>::<span class="ident">Rng</span>;
<span class="kw">use</span> <span class="ident">std</span>::{<span class="ident">io</span>, <span class="ident">cmp</span>};
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>::<span class="ident">Write</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">fs</span>::<span class="ident">File</span>;
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">roundtrip</span>() {
<span class="comment">// More loops = more random testing, but also more test wait time</span>
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">10</span> {
<span class="kw">for</span> <span class="ident">path</span> <span class="kw">in</span> <span class="ident">glob</span>::<span class="ident">glob</span>(<span class="string">"tests/pngsuite/*.png"</span>).<span class="ident">unwrap</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">r</span><span class="op">|</span> <span class="ident">r</span>.<span class="ident">unwrap</span>()) {
<span class="kw">if</span> <span class="ident">path</span>.<span class="ident">file_name</span>().<span class="ident">unwrap</span>().<span class="ident">to_str</span>().<span class="ident">unwrap</span>().<span class="ident">starts_with</span>(<span class="string">"x"</span>) {
<span class="comment">// x* files are expected to fail to decode</span>
<span class="kw">continue</span>;
}
<span class="comment">// Decode image</span>
<span class="kw">let</span> <span class="ident">decoder</span> <span class="op">=</span> ::<span class="ident">Decoder</span>::<span class="ident">new</span>(<span class="ident">File</span>::<span class="ident">open</span>(<span class="ident">path</span>).<span class="ident">unwrap</span>());
<span class="kw">let</span> (<span class="ident">info</span>, <span class="kw-2">mut</span> <span class="ident">reader</span>) <span class="op">=</span> <span class="ident">decoder</span>.<span class="ident">read_info</span>().<span class="ident">unwrap</span>();
<span class="kw">if</span> <span class="ident">info</span>.<span class="ident">line_size</span> <span class="op">!</span><span class="op">=</span> <span class="number">32</span> {
<span class="comment">// TODO encoding only works with line size 32?</span>
<span class="kw">continue</span>;
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0</span>; <span class="ident">info</span>.<span class="ident">buffer_size</span>()];
<span class="ident">reader</span>.<span class="ident">next_frame</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>();
<span class="comment">// Encode decoded image</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">out</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">new</span>();
{
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">wrapper</span> <span class="op">=</span> <span class="ident">RandomChunkWriter</span> {
<span class="ident">rng</span>: <span class="self">self</span>::<span class="ident">rand</span>::<span class="ident">thread_rng</span>(),
<span class="ident">w</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">out</span>
};
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">encoder</span> <span class="op">=</span> <span class="ident">Encoder</span>::<span class="ident">new</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">wrapper</span>, <span class="ident">info</span>.<span class="ident">width</span>, <span class="ident">info</span>.<span class="ident">height</span>).<span class="ident">write_header</span>().<span class="ident">unwrap</span>();
<span class="ident">encoder</span>.<span class="ident">write_image_data</span>(<span class="kw-2">&</span><span class="ident">buf</span>).<span class="ident">unwrap</span>();
}
<span class="comment">// Decode encoded decoded image</span>
<span class="kw">let</span> <span class="ident">decoder</span> <span class="op">=</span> ::<span class="ident">Decoder</span>::<span class="ident">new</span>(<span class="kw-2">&</span><span class="kw-2">*</span><span class="ident">out</span>);
<span class="kw">let</span> (<span class="ident">info</span>, <span class="kw-2">mut</span> <span class="ident">reader</span>) <span class="op">=</span> <span class="ident">decoder</span>.<span class="ident">read_info</span>().<span class="ident">unwrap</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf2</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0</span>; <span class="ident">info</span>.<span class="ident">buffer_size</span>()];
<span class="ident">reader</span>.<span class="ident">next_frame</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf2</span>).<span class="ident">unwrap</span>();
<span class="comment">// check if the encoded image is ok:</span>
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">buf</span>, <span class="ident">buf2</span>);
}
}
}
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">expect_error_on_wrong_image_len</span>() <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> {
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>::<span class="ident">Cursor</span>;
<span class="kw">let</span> <span class="ident">width</span> <span class="op">=</span> <span class="number">10</span>;
<span class="kw">let</span> <span class="ident">height</span> <span class="op">=</span> <span class="number">10</span>;
<span class="kw">let</span> <span class="ident">output</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0u8</span>; <span class="number">1024</span>];
<span class="kw">let</span> <span class="ident">writer</span> <span class="op">=</span> <span class="ident">Cursor</span>::<span class="ident">new</span>(<span class="ident">output</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">encoder</span> <span class="op">=</span> <span class="ident">Encoder</span>::<span class="ident">new</span>(<span class="ident">writer</span>, <span class="ident">width</span> <span class="kw">as</span> <span class="ident">u32</span>, <span class="ident">height</span> <span class="kw">as</span> <span class="ident">u32</span>);
<span class="ident">encoder</span>.<span class="ident">set</span>(<span class="ident">BitDepth</span>::<span class="ident">Eight</span>);
<span class="ident">encoder</span>.<span class="ident">set</span>(<span class="ident">ColorType</span>::<span class="ident">RGB</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">png_writer</span> <span class="op">=</span> <span class="ident">encoder</span>.<span class="ident">write_header</span>()<span class="question-mark">?</span>;
<span class="kw">let</span> <span class="ident">correct_image_size</span> <span class="op">=</span> <span class="ident">width</span> <span class="op">*</span> <span class="ident">height</span> <span class="op">*</span> <span class="number">3</span>;
<span class="kw">let</span> <span class="ident">image</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0u8</span>; <span class="ident">correct_image_size</span> <span class="op">+</span> <span class="number">1</span>];
<span class="kw">let</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">png_writer</span>.<span class="ident">write_image_data</span>(<span class="ident">image</span>.<span class="ident">as_ref</span>());
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">result</span>.<span class="ident">is_err</span>());
<span class="prelude-val">Ok</span>(())
}
<span class="doccomment">/// A Writer that only writes a few bytes at a time</span>
<span class="kw">struct</span> <span class="ident">RandomChunkWriter</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">R</span>: <span class="ident">Rng</span>, <span class="ident">W</span>: <span class="ident">Write</span> <span class="op">+</span> <span class="lifetime">'a</span><span class="op">></span> {
<span class="ident">rng</span>: <span class="ident">R</span>,
<span class="ident">w</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="kw-2">mut</span> <span class="ident">W</span>
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">R</span>: <span class="ident">Rng</span>, <span class="ident">W</span>: <span class="ident">Write</span> <span class="op">+</span> <span class="lifetime">'a</span><span class="op">></span> <span class="ident">Write</span> <span class="kw">for</span> <span class="ident">RandomChunkWriter</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">R</span>, <span class="ident">W</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-</span><span class="op">></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> {
<span class="comment">// choose a random length to write</span>
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">cmp</span>::<span class="ident">min</span>(<span class="self">self</span>.<span class="ident">rng</span>.<span class="ident">gen_range</span>(<span class="number">1</span>, <span class="number">50</span>), <span class="ident">buf</span>.<span class="ident">len</span>());
<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">write</span>(<span class="kw-2">&</span><span class="ident">buf</span>[<span class="number">0</span>..<span class="ident">len</span>])
}
<span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> {
<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">flush</span>()
}
}
}</pre></div>
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