/* * JavaScript Load Image Meta * https://github.com/blueimp/JavaScript-Load-Image * * Copyright 2013, Sebastian Tschan * https://blueimp.net * * Image meta data handling implementation * based on the help and contribution of * Achim Stöhr. * * Licensed under the MIT license: * http://www.opensource.org/licenses/MIT */ /* global define, Blob */ ;(function (factory) { 'use strict' if (typeof define === 'function' && define.amd) { // Register as an anonymous AMD module: define(['./load-image'], factory) } else if (typeof module === 'object' && module.exports) { factory(require('./load-image')) } else { // Browser globals: factory(window.loadImage) } }(function (loadImage) { 'use strict' var hasblobSlice = window.Blob && (Blob.prototype.slice || Blob.prototype.webkitSlice || Blob.prototype.mozSlice) loadImage.blobSlice = hasblobSlice && function () { var slice = this.slice || this.webkitSlice || this.mozSlice return slice.apply(this, arguments) } loadImage.metaDataParsers = { jpeg: { 0xffe1: [] // APP1 marker } } // Parses image meta data and calls the callback with an object argument // with the following properties: // * imageHead: The complete image head as ArrayBuffer (Uint8Array for IE10) // The options arguments accepts an object and supports the following properties: // * maxMetaDataSize: Defines the maximum number of bytes to parse. // * disableImageHead: Disables creating the imageHead property. loadImage.parseMetaData = function (file, callback, options, data) { options = options || {} data = data || {} var that = this // 256 KiB should contain all EXIF/ICC/IPTC segments: var maxMetaDataSize = options.maxMetaDataSize || 262144 var noMetaData = !(window.DataView && file && file.size >= 12 && file.type === 'image/jpeg' && loadImage.blobSlice) if (noMetaData || !loadImage.readFile( loadImage.blobSlice.call(file, 0, maxMetaDataSize), function (e) { if (e.target.error) { // FileReader error console.log(e.target.error) callback(data) return } // Note on endianness: // Since the marker and length bytes in JPEG files are always // stored in big endian order, we can leave the endian parameter // of the DataView methods undefined, defaulting to big endian. var buffer = e.target.result var dataView = new DataView(buffer) var offset = 2 var maxOffset = dataView.byteLength - 4 var headLength = offset var markerBytes var markerLength var parsers var i // Check for the JPEG marker (0xffd8): if (dataView.getUint16(0) === 0xffd8) { while (offset < maxOffset) { markerBytes = dataView.getUint16(offset) // Search for APPn (0xffeN) and COM (0xfffe) markers, // which contain application-specific meta-data like // Exif, ICC and IPTC data and text comments: if ((markerBytes >= 0xffe0 && markerBytes <= 0xffef) || markerBytes === 0xfffe) { // The marker bytes (2) are always followed by // the length bytes (2), indicating the length of the // marker segment, which includes the length bytes, // but not the marker bytes, so we add 2: markerLength = dataView.getUint16(offset + 2) + 2 if (offset + markerLength > dataView.byteLength) { console.log('Invalid meta data: Invalid segment size.') break } parsers = loadImage.metaDataParsers.jpeg[markerBytes] if (parsers) { for (i = 0; i < parsers.length; i += 1) { parsers[i].call( that, dataView, offset, markerLength, data, options ) } } offset += markerLength headLength = offset } else { // Not an APPn or COM marker, probably safe to // assume that this is the end of the meta data break } } // Meta length must be longer than JPEG marker (2) // plus APPn marker (2), followed by length bytes (2): if (!options.disableImageHead && headLength > 6) { if (buffer.slice) { data.imageHead = buffer.slice(0, headLength) } else { // Workaround for IE10, which does not yet // support ArrayBuffer.slice: data.imageHead = new Uint8Array(buffer) .subarray(0, headLength) } } } else { console.log('Invalid JPEG file: Missing JPEG marker.') } callback(data) }, 'readAsArrayBuffer' )) { callback(data) } } // Determines if meta data should be loaded automatically: loadImage.hasMetaOption = function (options) { return options.meta } var originalTransform = loadImage.transform loadImage.transform = function (img, options, callback, file, data) { if (loadImage.hasMetaOption(options || {})) { loadImage.parseMetaData(file, function (data) { originalTransform.call(loadImage, img, options, callback, file, data) }, options, data) } else { originalTransform.apply(loadImage, arguments) } } }))