alpaca/dist/lib/blueimp-canvas-to-blob/js/canvas-to-blob.js

Alpaca provides the easiest and fastest way to generate interactive forms for the web and mobile devices. It runs simply as HTML5 or more elaborately using Bootstrap, jQuery Mobile or jQuery UI. Alpaca uses Handlebars to process JSON schema and provide

/*
 * JavaScript Canvas to Blob 2.0.5
 * https://github.com/blueimp/JavaScript-Canvas-to-Blob
 *
 * Copyright 2012, Sebastian Tschan
 * https://blueimp.net
 *
 * Licensed under the MIT license:
 * http://www.opensource.org/licenses/MIT
 *
 * Based on stackoverflow user Stoive's code snippet:
 * http://stackoverflow.com/q/4998908
 */

/*jslint nomen: true, regexp: true */
/*global window, atob, Blob, ArrayBuffer, Uint8Array, define */

(function (window) {
    'use strict';
    var CanvasPrototype = window.HTMLCanvasElement &&
            window.HTMLCanvasElement.prototype,
        hasBlobConstructor = window.Blob && (function () {
            try {
                return Boolean(new Blob());
            } catch (e) {
                return false;
            }
        }()),
        hasArrayBufferViewSupport = hasBlobConstructor && window.Uint8Array &&
            (function () {
                try {
                    return new Blob([new Uint8Array(100)]).size === 100;
                } catch (e) {
                    return false;
                }
            }()),
        BlobBuilder = window.BlobBuilder || window.WebKitBlobBuilder ||
            window.MozBlobBuilder || window.MSBlobBuilder,
        dataURLtoBlob = (hasBlobConstructor || BlobBuilder) && window.atob &&
            window.ArrayBuffer && window.Uint8Array && function (dataURI) {
                var byteString,
                    arrayBuffer,
                    intArray,
                    i,
                    mimeString,
                    bb;
                if (dataURI.split(',')[0].indexOf('base64') >= 0) {
                    // Convert base64 to raw binary data held in a string:
                    byteString = atob(dataURI.split(',')[1]);
                } else {
                    // Convert base64/URLEncoded data component to raw binary data:
                    byteString = decodeURIComponent(dataURI.split(',')[1]);
                }
                // Write the bytes of the string to an ArrayBuffer:
                arrayBuffer = new ArrayBuffer(byteString.length);
                intArray = new Uint8Array(arrayBuffer);
                for (i = 0; i < byteString.length; i += 1) {
                    intArray[i] = byteString.charCodeAt(i);
                }
                // Separate out the mime component:
                mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];
                // Write the ArrayBuffer (or ArrayBufferView) to a blob:
                if (hasBlobConstructor) {
                    return new Blob(
                        [hasArrayBufferViewSupport ? intArray : arrayBuffer],
                        {type: mimeString}
                    );
                }
                bb = new BlobBuilder();
                bb.append(arrayBuffer);
                return bb.getBlob(mimeString);
            };
    if (window.HTMLCanvasElement && !CanvasPrototype.toBlob) {
        if (CanvasPrototype.mozGetAsFile) {
            CanvasPrototype.toBlob = function (callback, type, quality) {
                if (quality && CanvasPrototype.toDataURL && dataURLtoBlob) {
                    callback(dataURLtoBlob(this.toDataURL(type, quality)));
                } else {
                    callback(this.mozGetAsFile('blob', type));
                }
            };
        } else if (CanvasPrototype.toDataURL && dataURLtoBlob) {
            CanvasPrototype.toBlob = function (callback, type, quality) {
                callback(dataURLtoBlob(this.toDataURL(type, quality)));
            };
        }
    }
    if (typeof define === 'function' && define.amd) {
        define(function () {
            return dataURLtoBlob;
        });
    } else {
        window.dataURLtoBlob = dataURLtoBlob;
    }
}(this));