@cleerlycode/cornerstone-wado-image-loader
Version:
Cornerstone ImageLoader for DICOM WADO-URI
142 lines (102 loc) • 5.32 kB
HTML
<html lang="en">
<head>
<meta charset="utf-8">
<title>imageLoader/decodeJPEGBaseline8BitColor.js - Documentation</title>
<script src="scripts/prettify/prettify.js"></script>
<script src="scripts/prettify/lang-css.js"></script>
<!--[if lt IE 9]>
<script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->
<link type="text/css" rel="stylesheet" href="styles/prettify.css">
<link type="text/css" rel="stylesheet" href="styles/jsdoc.css">
</head>
<body>
<input type="checkbox" id="nav-trigger" class="nav-trigger" />
<label for="nav-trigger" class="navicon-button x">
<div class="navicon"></div>
</label>
<label for="nav-trigger" class="overlay"></label>
<nav>
<h2><a href="index.html">Home</a></h2><h3>Global</h3><ul><li><a href="global.html#addTask">addTask</a></li><li><a href="global.html#arrayBufferToString">arrayBufferToString</a></li><li><a href="global.html#cacheSizeInBytes">cacheSizeInBytes</a></li><li><a href="global.html#cancelTask">cancelTask</a></li><li><a href="global.html#framesAreFragmented">framesAreFragmented</a></li><li><a href="global.html#getNumberString">getNumberString</a></li><li><a href="global.html#getNumberValues">getNumberValues</a></li><li><a href="global.html#getStatistics">getStatistics</a></li><li><a href="global.html#getTransferSyntaxForContentType">getTransferSyntaxForContentType</a></li><li><a href="global.html#getUncompressedImageFrame">getUncompressedImageFrame</a></li><li><a href="global.html#getValue">getValue</a></li><li><a href="global.html#handleMessageFromWorker">handleMessageFromWorker</a></li><li><a href="global.html#handler">handler</a></li><li><a href="global.html#initialize">initialize</a></li><li><a href="global.html#loadCodecs">loadCodecs</a></li><li><a href="global.html#loadWebWorkerTask">loadWebWorkerTask</a></li><li><a href="global.html#registerLoaders">registerLoaders</a></li><li><a href="global.html#registerTaskHandler">registerTaskHandler</a></li><li><a href="global.html#setPixelDataType">setPixelDataType</a></li><li><a href="global.html#setTaskPriority">setTaskPriority</a></li><li><a href="global.html#spawnWebWorker">spawnWebWorker</a></li><li><a href="global.html#startTaskOnWebWorker">startTaskOnWebWorker</a></li><li><a href="global.html#unpackBinaryFrame">unpackBinaryFrame</a></li></ul>
</nav>
<div id="main">
<h1 class="page-title">imageLoader/decodeJPEGBaseline8BitColor.js</h1>
<section>
<article>
<pre class="prettyprint source linenums"><code>import getMinMax from '../shared/getMinMax.js';
/**
* Special decoder for 8 bit jpeg that leverages the browser's built in JPEG decoder for increased performance
*/
function arrayBufferToString (buffer) {
return binaryToString(String.fromCharCode.apply(null, Array.prototype.slice.apply(new Uint8Array(buffer))));
}
function binaryToString (binary) {
let error;
try {
return decodeURIComponent(escape(binary));
} catch (_error) {
error = _error;
if (error instanceof URIError) {
return binary;
}
throw error;
}
}
function decodeJPEGBaseline8BitColor (imageFrame, pixelData, canvas) {
const start = new Date().getTime();
const imgBlob = new Blob([pixelData], { type: 'image/jpeg' });
return new Promise((resolve, reject) => {
const fileReader = new FileReader();
if (fileReader.readAsBinaryString === undefined) {
fileReader.readAsArrayBuffer(imgBlob);
} else {
fileReader.readAsBinaryString(imgBlob); // doesn't work on IE11
}
fileReader.onload = function () {
const img = new Image();
img.onload = function () {
canvas.height = img.height;
canvas.width = img.width;
imageFrame.rows = img.height;
imageFrame.columns = img.width;
const context = canvas.getContext('2d');
context.drawImage(this, 0, 0);
const imageData = context.getImageData(0, 0, img.width, img.height);
const end = new Date().getTime();
imageFrame.pixelData = imageData.data;
imageFrame.imageData = imageData;
imageFrame.decodeTimeInMS = end - start;
// calculate smallest and largest PixelValue
const minMax = getMinMax(imageFrame.pixelData);
imageFrame.smallestPixelValue = minMax.min;
imageFrame.largestPixelValue = minMax.max;
resolve(imageFrame);
};
img.onerror = function (error) {
reject(error);
};
if (fileReader.readAsBinaryString === undefined) {
img.src = `data:image/jpeg;base64,${window.btoa(arrayBufferToString(fileReader.result))}`;
} else {
img.src = `data:image/jpeg;base64,${window.btoa(fileReader.result)}`; // doesn't work on IE11
}
};
fileReader.onerror = (e) => {
reject(e);
};
});
}
export default decodeJPEGBaseline8BitColor;
</code></pre>
</article>
</section>
</div>
<br class="clear">
<footer>
Documentation generated by <a href="https://github.com/jsdoc3/jsdoc">JSDoc 3.5.5</a> using the <a href="https://github.com/clenemt/docdash">docdash</a> theme.
</footer>
<script>prettyPrint();</script>
<script src="scripts/linenumber.js"></script>
</body>
</html>