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302 lines
10 KiB
JavaScript
302 lines
10 KiB
JavaScript
/*
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* JavaScript Load Image 1.10.0
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* https://github.com/blueimp/JavaScript-Load-Image
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*
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* Copyright 2011, Sebastian Tschan
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* https://blueimp.net
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*
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* Licensed under the MIT license:
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* http://www.opensource.org/licenses/MIT
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*/
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/*jslint nomen: true */
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/*global define, window, document, URL, webkitURL, Blob, File, FileReader */
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(function ($) {
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'use strict';
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// Loads an image for a given File object.
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// Invokes the callback with an img or optional canvas
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// element (if supported by the browser) as parameter:
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var loadImage = function (file, callback, options) {
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var img = document.createElement('img'),
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url,
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oUrl;
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img.onerror = callback;
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img.onload = function () {
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if (oUrl && !(options && options.noRevoke)) {
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loadImage.revokeObjectURL(oUrl);
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}
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if (callback) {
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callback(loadImage.scale(img, options));
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}
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};
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if (loadImage.isInstanceOf('Blob', file) ||
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// Files are also Blob instances, but some browsers
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// (Firefox 3.6) support the File API but not Blobs:
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loadImage.isInstanceOf('File', file)) {
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url = oUrl = loadImage.createObjectURL(file);
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// Store the file type for resize processing:
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img._type = file.type;
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} else if (typeof file === 'string') {
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url = file;
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if (options && options.crossOrigin) {
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img.crossOrigin = options.crossOrigin;
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}
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} else {
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return false;
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}
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if (url) {
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img.src = url;
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return img;
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}
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return loadImage.readFile(file, function (e) {
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var target = e.target;
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if (target && target.result) {
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img.src = target.result;
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} else {
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if (callback) {
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callback(e);
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}
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}
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});
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},
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// The check for URL.revokeObjectURL fixes an issue with Opera 12,
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// which provides URL.createObjectURL but doesn't properly implement it:
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urlAPI = (window.createObjectURL && window) ||
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(window.URL && URL.revokeObjectURL && URL) ||
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(window.webkitURL && webkitURL);
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loadImage.isInstanceOf = function (type, obj) {
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// Cross-frame instanceof check
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return Object.prototype.toString.call(obj) === '[object ' + type + ']';
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};
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// Transform image coordinates, allows to override e.g.
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// the canvas orientation based on the orientation option,
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// gets canvas, options passed as arguments:
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loadImage.transformCoordinates = function () {
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return;
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};
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// Returns transformed options, allows to override e.g.
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// maxWidth, maxHeight and crop options based on the aspectRatio.
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// gets img, options passed as arguments:
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loadImage.getTransformedOptions = function (img, options) {
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var aspectRatio = options.aspectRatio,
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newOptions,
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i,
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width,
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height;
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if (!aspectRatio) {
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return options;
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}
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newOptions = {};
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for (i in options) {
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if (options.hasOwnProperty(i)) {
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newOptions[i] = options[i];
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}
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}
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newOptions.crop = true;
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width = img.naturalWidth || img.width;
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height = img.naturalHeight || img.height;
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if (width / height > aspectRatio) {
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newOptions.maxWidth = height * aspectRatio;
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newOptions.maxHeight = height;
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} else {
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newOptions.maxWidth = width;
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newOptions.maxHeight = width / aspectRatio;
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}
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return newOptions;
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};
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// Canvas render method, allows to override the
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// rendering e.g. to work around issues on iOS:
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loadImage.renderImageToCanvas = function (
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canvas,
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img,
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sourceX,
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sourceY,
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sourceWidth,
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sourceHeight,
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destX,
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destY,
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destWidth,
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destHeight
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) {
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canvas.getContext('2d').drawImage(
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img,
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sourceX,
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sourceY,
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sourceWidth,
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sourceHeight,
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destX,
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destY,
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destWidth,
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destHeight
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);
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return canvas;
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};
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// This method is used to determine if the target image
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// should be a canvas element:
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loadImage.hasCanvasOption = function (options) {
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return options.canvas || options.crop || options.aspectRatio;
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};
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// Scales and/or crops the given image (img or canvas HTML element)
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// using the given options.
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// Returns a canvas object if the browser supports canvas
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// and the hasCanvasOption method returns true or a canvas
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// object is passed as image, else the scaled image:
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loadImage.scale = function (img, options) {
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options = options || {};
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var canvas = document.createElement('canvas'),
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useCanvas = img.getContext ||
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(loadImage.hasCanvasOption(options) && canvas.getContext),
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width = img.naturalWidth || img.width,
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height = img.naturalHeight || img.height,
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destWidth = width,
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destHeight = height,
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maxWidth,
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maxHeight,
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minWidth,
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minHeight,
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sourceWidth,
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sourceHeight,
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sourceX,
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sourceY,
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tmp,
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scaleUp = function () {
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var scale = Math.max(
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(minWidth || destWidth) / destWidth,
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(minHeight || destHeight) / destHeight
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);
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if (scale > 1) {
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destWidth = destWidth * scale;
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destHeight = destHeight * scale;
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}
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},
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scaleDown = function () {
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var scale = Math.min(
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(maxWidth || destWidth) / destWidth,
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(maxHeight || destHeight) / destHeight
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);
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if (scale < 1) {
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destWidth = destWidth * scale;
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destHeight = destHeight * scale;
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}
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};
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if (useCanvas) {
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options = loadImage.getTransformedOptions(img, options);
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sourceX = options.left || 0;
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sourceY = options.top || 0;
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if (options.sourceWidth) {
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sourceWidth = options.sourceWidth;
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if (options.right !== undefined && options.left === undefined) {
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sourceX = width - sourceWidth - options.right;
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}
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} else {
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sourceWidth = width - sourceX - (options.right || 0);
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}
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if (options.sourceHeight) {
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sourceHeight = options.sourceHeight;
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if (options.bottom !== undefined && options.top === undefined) {
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sourceY = height - sourceHeight - options.bottom;
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}
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} else {
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sourceHeight = height - sourceY - (options.bottom || 0);
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}
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destWidth = sourceWidth;
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destHeight = sourceHeight;
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}
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maxWidth = options.maxWidth;
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maxHeight = options.maxHeight;
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minWidth = options.minWidth;
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minHeight = options.minHeight;
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if (useCanvas && maxWidth && maxHeight && options.crop) {
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destWidth = maxWidth;
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destHeight = maxHeight;
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tmp = sourceWidth / sourceHeight - maxWidth / maxHeight;
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if (tmp < 0) {
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sourceHeight = maxHeight * sourceWidth / maxWidth;
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if (options.top === undefined && options.bottom === undefined) {
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sourceY = (height - sourceHeight) / 2;
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}
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} else if (tmp > 0) {
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sourceWidth = maxWidth * sourceHeight / maxHeight;
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if (options.left === undefined && options.right === undefined) {
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sourceX = (width - sourceWidth) / 2;
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}
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}
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} else {
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if (options.contain || options.cover) {
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minWidth = maxWidth = maxWidth || minWidth;
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minHeight = maxHeight = maxHeight || minHeight;
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}
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if (options.cover) {
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scaleDown();
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scaleUp();
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} else {
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scaleUp();
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scaleDown();
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}
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}
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if (useCanvas) {
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canvas.width = destWidth;
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canvas.height = destHeight;
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loadImage.transformCoordinates(
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canvas,
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options
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);
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return loadImage.renderImageToCanvas(
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canvas,
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img,
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sourceX,
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sourceY,
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sourceWidth,
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sourceHeight,
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0,
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0,
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destWidth,
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destHeight
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);
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}
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img.width = destWidth;
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img.height = destHeight;
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return img;
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};
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loadImage.createObjectURL = function (file) {
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return urlAPI ? urlAPI.createObjectURL(file) : false;
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};
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loadImage.revokeObjectURL = function (url) {
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return urlAPI ? urlAPI.revokeObjectURL(url) : false;
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};
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// Loads a given File object via FileReader interface,
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// invokes the callback with the event object (load or error).
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// The result can be read via event.target.result:
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loadImage.readFile = function (file, callback, method) {
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if (window.FileReader) {
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var fileReader = new FileReader();
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fileReader.onload = fileReader.onerror = callback;
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method = method || 'readAsDataURL';
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if (fileReader[method]) {
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fileReader[method](file);
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return fileReader;
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}
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}
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return false;
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};
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if (typeof define === 'function' && define.amd) {
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define(function () {
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return loadImage;
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});
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} else {
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$.loadImage = loadImage;
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}
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}(this));
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