<!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 `/home/sangenya/.cargo/registry/src/github.com-1ecc6299db9ec823/png-0.11.0/src/encoder.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>encoder.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">extern</span> <span class="kw">crate</span> <span class="ident">deflate</span>;
<span class="kw">use</span> <span class="ident">std::borrow::Cow</span>;
<span class="kw">use</span> <span class="ident">std::io</span>::{<span class="self">self</span>, <span class="ident">Write</span>};
<span class="kw">use</span> <span class="ident">std::result</span>;
<span class="kw">use</span> <span class="ident">std::fmt</span>;
<span class="kw">use</span> <span class="ident">std::error</span>;
<span class="kw">use</span> <span class="ident">chunk</span>;
<span class="kw">use</span> <span class="ident">crc::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="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::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::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::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::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::Formatter</span>) <span class="op">-</span><span class="op">></span> <span class="ident">result::Result</span><span class="op"><</span>(), <span class="ident">fmt::Error</span><span class="op">></span> {
<span class="macro">write!</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::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::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::Error</span>) <span class="op">-</span><span class="op">></span> <span class="ident">EncodingError</span> {
<span class="ident">EncodingError::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::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::Error</span> {
<span class="ident">io::Error::new</span>(<span class="ident">io::ErrorKind::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::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::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::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">/// 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="self">self</span>.<span class="ident">w</span>.<span class="ident">write</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="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="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="self">self</span>.<span class="ident">write_chunk</span>(<span class="ident">chunk::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="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="self">self</span>.<span class="ident">w</span>.<span class="ident">write</span>(<span class="kw-2">&</span><span class="ident">name</span>));
<span class="macro">try!</span>(<span class="self">self</span>.<span class="ident">w</span>.<span class="ident">write</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::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="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="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="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</span>.<span class="ident">len</span>() <span class="op"><</span> <span class="ident">data_size</span> <span class="op">|</span><span class="op">|</span> <span class="ident">data_size</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">EncodingError::Format</span>(<span class="string">"not enough image data provided"</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::write::ZlibEncoder::new</span>(<span class="ident">Vec::new</span>(), <span class="ident">deflate::Compression::Fast</span>);
<span class="kw">let</span> <span class="ident">filter_method</span> <span class="op">=</span> <span class="ident">FilterType::Sub</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">::utils::copy_memory</span>(<span class="kw-2">&</span><span class="ident">line</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">current</span>);
<span class="macro">try!</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="ident">zlib</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span><span class="ident">current</span>));
<span class="ident">::utils::copy_memory</span>(<span class="kw-2">&</span><span class="ident">current</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">prev</span>);
}
<span class="self">self</span>.<span class="ident">write_chunk</span>(<span class="ident">chunk::IDAT</span>, <span class="kw-2">&</span><span class="macro">try!</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::IEND</span>, <span class="kw-2">&</span>[]);
}
}
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">roundtrip</span>() {
<span class="kw">use</span> <span class="ident">std::fs::File</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::new</span>(<span class="ident">File::open</span>(<span class="string">"tests/pngsuite/basi0g01.png"</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">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> <span class="macro">vec!</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::new</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::new</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">out</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::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="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="ident">buf</span>, <span class="ident">buf2</span>);
}
</pre></div>
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