436 lines
12 KiB
JavaScript
436 lines
12 KiB
JavaScript
// TODO: including these in blob-util.ts causes typedoc to generate docs for them,
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// even with --excludePrivate ¯\_(ツ)_/¯
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/** @private */
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function loadImage(src, crossOrigin) {
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return new Promise(function (resolve, reject) {
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var img = new Image();
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if (crossOrigin) {
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img.crossOrigin = crossOrigin;
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}
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img.onload = function () {
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resolve(img);
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};
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img.onerror = reject;
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img.src = src;
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});
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}
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/** @private */
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function imgToCanvas(img) {
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var canvas = document.createElement('canvas');
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canvas.width = img.width;
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canvas.height = img.height;
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// copy the image contents to the canvas
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var context = canvas.getContext('2d');
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context.drawImage(img, 0, 0, img.width, img.height, 0, 0, img.width, img.height);
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return canvas;
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}
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/* global Promise, Image, Blob, FileReader, atob, btoa,
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BlobBuilder, MSBlobBuilder, MozBlobBuilder, WebKitBlobBuilder, webkitURL */
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/**
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* Shim for
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* [`new Blob()`](https://developer.mozilla.org/en-US/docs/Web/API/Blob.Blob)
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* to support
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* [older browsers that use the deprecated `BlobBuilder` API](http://caniuse.com/blob).
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*
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* Example:
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*
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* ```js
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* var myBlob = blobUtil.createBlob(['hello world'], {type: 'text/plain'});
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* ```
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*
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* @param parts - content of the Blob
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* @param properties - usually `{type: myContentType}`,
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* you can also pass a string for the content type
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* @returns Blob
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*/
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function createBlob(parts, properties) {
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parts = parts || [];
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properties = properties || {};
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if (typeof properties === 'string') {
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properties = { type: properties }; // infer content type
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}
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try {
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return new Blob(parts, properties);
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}
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catch (e) {
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if (e.name !== 'TypeError') {
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throw e;
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}
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var Builder = typeof BlobBuilder !== 'undefined'
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? BlobBuilder : typeof MSBlobBuilder !== 'undefined'
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? MSBlobBuilder : typeof MozBlobBuilder !== 'undefined'
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? MozBlobBuilder : WebKitBlobBuilder;
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var builder = new Builder();
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for (var i = 0; i < parts.length; i += 1) {
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builder.append(parts[i]);
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}
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return builder.getBlob(properties.type);
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}
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}
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/**
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* Shim for
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* [`URL.createObjectURL()`](https://developer.mozilla.org/en-US/docs/Web/API/URL.createObjectURL)
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* to support browsers that only have the prefixed
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* `webkitURL` (e.g. Android <4.4).
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*
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* Example:
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*
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* ```js
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* var myUrl = blobUtil.createObjectURL(blob);
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* ```
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*
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* @param blob
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* @returns url
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*/
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function createObjectURL(blob) {
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return (typeof URL !== 'undefined' ? URL : webkitURL).createObjectURL(blob);
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}
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/**
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* Shim for
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* [`URL.revokeObjectURL()`](https://developer.mozilla.org/en-US/docs/Web/API/URL.revokeObjectURL)
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* to support browsers that only have the prefixed
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* `webkitURL` (e.g. Android <4.4).
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*
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* Example:
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*
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* ```js
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* blobUtil.revokeObjectURL(myUrl);
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* ```
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*
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* @param url
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*/
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function revokeObjectURL(url) {
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return (typeof URL !== 'undefined' ? URL : webkitURL).revokeObjectURL(url);
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}
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/**
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* Convert a `Blob` to a binary string.
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*
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* Example:
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*
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* ```js
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* blobUtil.blobToBinaryString(blob).then(function (binaryString) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* @param blob
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* @returns Promise that resolves with the binary string
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*/
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function blobToBinaryString(blob) {
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return new Promise(function (resolve, reject) {
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var reader = new FileReader();
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var hasBinaryString = typeof reader.readAsBinaryString === 'function';
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reader.onloadend = function () {
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var result = reader.result || '';
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if (hasBinaryString) {
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return resolve(result);
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}
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resolve(arrayBufferToBinaryString(result));
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};
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reader.onerror = reject;
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if (hasBinaryString) {
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reader.readAsBinaryString(blob);
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}
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else {
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reader.readAsArrayBuffer(blob);
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}
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});
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}
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/**
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* Convert a base64-encoded string to a `Blob`.
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*
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* Example:
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*
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* ```js
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* var blob = blobUtil.base64StringToBlob(base64String);
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* ```
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* @param base64 - base64-encoded string
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* @param type - the content type (optional)
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* @returns Blob
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*/
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function base64StringToBlob(base64, type) {
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var parts = [binaryStringToArrayBuffer(atob(base64))];
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return type ? createBlob(parts, { type: type }) : createBlob(parts);
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}
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/**
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* Convert a binary string to a `Blob`.
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*
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* Example:
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*
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* ```js
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* var blob = blobUtil.binaryStringToBlob(binaryString);
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* ```
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*
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* @param binary - binary string
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* @param type - the content type (optional)
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* @returns Blob
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*/
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function binaryStringToBlob(binary, type) {
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return base64StringToBlob(btoa(binary), type);
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}
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/**
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* Convert a `Blob` to a binary string.
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*
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* Example:
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*
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* ```js
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* blobUtil.blobToBase64String(blob).then(function (base64String) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* @param blob
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* @returns Promise that resolves with the binary string
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*/
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function blobToBase64String(blob) {
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return blobToBinaryString(blob).then(btoa);
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}
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/**
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* Convert a data URL string
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* (e.g. `'data:image/png;base64,iVBORw0KG...'`)
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* to a `Blob`.
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*
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* Example:
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*
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* ```js
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* var blob = blobUtil.dataURLToBlob(dataURL);
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* ```
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*
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* @param dataURL - dataURL-encoded string
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* @returns Blob
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*/
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function dataURLToBlob(dataURL) {
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var type = dataURL.match(/data:([^;]+)/)[1];
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var base64 = dataURL.replace(/^[^,]+,/, '');
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var buff = binaryStringToArrayBuffer(atob(base64));
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return createBlob([buff], { type: type });
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}
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/**
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* Convert a `Blob` to a data URL string
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* (e.g. `'data:image/png;base64,iVBORw0KG...'`).
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*
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* Example:
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*
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* ```js
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* var dataURL = blobUtil.blobToDataURL(blob);
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* ```
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*
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* @param blob
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* @returns Promise that resolves with the data URL string
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*/
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function blobToDataURL(blob) {
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return blobToBase64String(blob).then(function (base64String) {
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return 'data:' + blob.type + ';base64,' + base64String;
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});
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}
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/**
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* Convert an image's `src` URL to a data URL by loading the image and painting
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* it to a `canvas`.
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*
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* Note: this will coerce the image to the desired content type, and it
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* will only paint the first frame of an animated GIF.
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*
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* Examples:
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*
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* ```js
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* blobUtil.imgSrcToDataURL('http://mysite.com/img.png').then(function (dataURL) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* ```js
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* blobUtil.imgSrcToDataURL('http://some-other-site.com/img.jpg', 'image/jpeg',
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* 'Anonymous', 1.0).then(function (dataURL) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* @param src - image src
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* @param type - the content type (optional, defaults to 'image/png')
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* @param crossOrigin - for CORS-enabled images, set this to
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* 'Anonymous' to avoid "tainted canvas" errors
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* @param quality - a number between 0 and 1 indicating image quality
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* if the requested type is 'image/jpeg' or 'image/webp'
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* @returns Promise that resolves with the data URL string
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*/
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function imgSrcToDataURL(src, type, crossOrigin, quality) {
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type = type || 'image/png';
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return loadImage(src, crossOrigin).then(imgToCanvas).then(function (canvas) {
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return canvas.toDataURL(type, quality);
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});
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}
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/**
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* Convert a `canvas` to a `Blob`.
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*
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* Examples:
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*
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* ```js
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* blobUtil.canvasToBlob(canvas).then(function (blob) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* Most browsers support converting a canvas to both `'image/png'` and `'image/jpeg'`. You may
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* also want to try `'image/webp'`, which will work in some browsers like Chrome (and in other browsers, will just fall back to `'image/png'`):
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*
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* ```js
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* blobUtil.canvasToBlob(canvas, 'image/webp').then(function (blob) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* @param canvas - HTMLCanvasElement
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* @param type - the content type (optional, defaults to 'image/png')
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* @param quality - a number between 0 and 1 indicating image quality
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* if the requested type is 'image/jpeg' or 'image/webp'
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* @returns Promise that resolves with the `Blob`
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*/
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function canvasToBlob(canvas, type, quality) {
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if (typeof canvas.toBlob === 'function') {
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return new Promise(function (resolve) {
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canvas.toBlob(resolve, type, quality);
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});
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}
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return Promise.resolve(dataURLToBlob(canvas.toDataURL(type, quality)));
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}
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/**
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* Convert an image's `src` URL to a `Blob` by loading the image and painting
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* it to a `canvas`.
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*
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* Note: this will coerce the image to the desired content type, and it
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* will only paint the first frame of an animated GIF.
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*
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* Examples:
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*
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* ```js
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* blobUtil.imgSrcToBlob('http://mysite.com/img.png').then(function (blob) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* ```js
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* blobUtil.imgSrcToBlob('http://some-other-site.com/img.jpg', 'image/jpeg',
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* 'Anonymous', 1.0).then(function (blob) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* @param src - image src
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* @param type - the content type (optional, defaults to 'image/png')
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* @param crossOrigin - for CORS-enabled images, set this to
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* 'Anonymous' to avoid "tainted canvas" errors
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* @param quality - a number between 0 and 1 indicating image quality
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* if the requested type is 'image/jpeg' or 'image/webp'
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* @returns Promise that resolves with the `Blob`
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*/
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function imgSrcToBlob(src, type, crossOrigin, quality) {
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type = type || 'image/png';
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return loadImage(src, crossOrigin).then(imgToCanvas).then(function (canvas) {
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return canvasToBlob(canvas, type, quality);
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});
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}
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/**
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* Convert an `ArrayBuffer` to a `Blob`.
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*
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* Example:
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*
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* ```js
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* var blob = blobUtil.arrayBufferToBlob(arrayBuff, 'audio/mpeg');
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* ```
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*
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* @param buffer
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* @param type - the content type (optional)
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* @returns Blob
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*/
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function arrayBufferToBlob(buffer, type) {
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return createBlob([buffer], type);
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}
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/**
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* Convert a `Blob` to an `ArrayBuffer`.
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*
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* Example:
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*
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* ```js
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* blobUtil.blobToArrayBuffer(blob).then(function (arrayBuff) {
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* // success
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* }).catch(function (err) {
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* // error
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* });
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* ```
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*
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* @param blob
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* @returns Promise that resolves with the `ArrayBuffer`
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*/
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function blobToArrayBuffer(blob) {
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return new Promise(function (resolve, reject) {
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var reader = new FileReader();
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reader.onloadend = function () {
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var result = reader.result || new ArrayBuffer(0);
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resolve(result);
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};
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reader.onerror = reject;
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reader.readAsArrayBuffer(blob);
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});
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}
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/**
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* Convert an `ArrayBuffer` to a binary string.
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*
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* Example:
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*
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* ```js
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* var myString = blobUtil.arrayBufferToBinaryString(arrayBuff)
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* ```
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*
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* @param buffer - array buffer
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* @returns binary string
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*/
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function arrayBufferToBinaryString(buffer) {
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var binary = '';
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var bytes = new Uint8Array(buffer);
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var length = bytes.byteLength;
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var i = -1;
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while (++i < length) {
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binary += String.fromCharCode(bytes[i]);
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}
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return binary;
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}
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/**
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* Convert a binary string to an `ArrayBuffer`.
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*
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* ```js
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* var myBuffer = blobUtil.binaryStringToArrayBuffer(binaryString)
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* ```
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*
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* @param binary - binary string
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* @returns array buffer
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*/
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function binaryStringToArrayBuffer(binary) {
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var length = binary.length;
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var buf = new ArrayBuffer(length);
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var arr = new Uint8Array(buf);
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var i = -1;
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while (++i < length) {
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arr[i] = binary.charCodeAt(i);
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}
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return buf;
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}
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export { createBlob, createObjectURL, revokeObjectURL, blobToBinaryString, base64StringToBlob, binaryStringToBlob, blobToBase64String, dataURLToBlob, blobToDataURL, imgSrcToDataURL, canvasToBlob, imgSrcToBlob, arrayBufferToBlob, blobToArrayBuffer, arrayBufferToBinaryString, binaryStringToArrayBuffer };
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