request_animation_frame.js

/**
* Copyright 2012-2016, Plotly, Inc.
* All rights reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/

// This code adapted from:
//
// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel

// MIT license


'use strict';

if(!Date.now) {
    Date.now = function() { return new Date().getTime(); };
}

var vendors = ['webkit', 'moz'];
for(var i = 0; i < vendors.length && !window.requestAnimationFrame; ++i) {
    var vp = vendors[i];
    window.requestAnimationFrame = window[vp + 'RequestAnimationFrame'];
    window.cancelAnimationFrame = (window[vp + 'CancelAnimationFrame'] ||
                                   window[vp + 'CancelRequestAnimationFrame']);
}
if(/iP(ad|hone|od).*OS 6/.test(window.navigator.userAgent) || // iOS6 is buggy
    !window.requestAnimationFrame || !window.cancelAnimationFrame) {
    var lastTime = 0;
    window.requestAnimationFrame = function(callback) {
        var now = Date.now();
        var nextTime = Math.max(lastTime + 16, now);
        return setTimeout(function() { callback(lastTime = nextTime); },
                          nextTime - now);
    };
    window.cancelAnimationFrame = clearTimeout;
}