411 lines
12 KiB
JavaScript
411 lines
12 KiB
JavaScript
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/*
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Smooth.js version 0.1.5
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Turn arrays into smooth functions.
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Copyright 2012 Spencer Cohen
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Licensed under MIT license (see "Smooth.js MIT license.txt")
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*/
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/*Constants (these are accessible by Smooth.WHATEVER in user space)
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*/
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(function() {
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var AbstractInterpolator, CubicInterpolator, Enum, LinearInterpolator, NearestInterpolator, PI, SincFilterInterpolator, Smooth, clipClamp, clipMirror, clipPeriodic, defaultConfig, getColumn, getType, isValidNumber, k, makeLanczosWindow, makeScaledFunction, makeSincKernel, normalizeScaleTo, root, shallowCopy, sin, sinc, v, validateNumber, validateVector,
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__hasProp = Object.prototype.hasOwnProperty,
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__extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor; child.__super__ = parent.prototype; return child; };
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Enum = {
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/*Interpolation methods
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*/
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METHOD_NEAREST: 'nearest',
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METHOD_LINEAR: 'linear',
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METHOD_CUBIC: 'cubic',
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METHOD_LANCZOS: 'lanczos',
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METHOD_SINC: 'sinc',
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/*Input clipping modes
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*/
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CLIP_CLAMP: 'clamp',
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CLIP_ZERO: 'zero',
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CLIP_PERIODIC: 'periodic',
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CLIP_MIRROR: 'mirror',
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/* Constants for control over the cubic interpolation tension
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*/
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CUBIC_TENSION_DEFAULT: 0,
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CUBIC_TENSION_CATMULL_ROM: 0
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};
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defaultConfig = {
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method: Enum.METHOD_CUBIC,
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cubicTension: Enum.CUBIC_TENSION_DEFAULT,
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clip: Enum.CLIP_CLAMP,
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scaleTo: 0,
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sincFilterSize: 2,
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sincWindow: void 0
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};
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/*Index clipping functions
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*/
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clipClamp = function(i, n) {
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return Math.max(0, Math.min(i, n - 1));
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};
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clipPeriodic = function(i, n) {
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i = i % n;
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if (i < 0) i += n;
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return i;
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};
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clipMirror = function(i, n) {
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var period;
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period = 2 * (n - 1);
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i = clipPeriodic(i, period);
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if (i > n - 1) i = period - i;
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return i;
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};
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/*
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Abstract scalar interpolation class which provides common functionality for all interpolators
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Subclasses must override interpolate().
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*/
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AbstractInterpolator = (function() {
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function AbstractInterpolator(array, config) {
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var clipHelpers;
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this.array = array.slice(0);
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this.length = this.array.length;
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clipHelpers = {
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clamp: this.clipHelperClamp,
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zero: this.clipHelperZero,
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periodic: this.clipHelperPeriodic,
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mirror: this.clipHelperMirror
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};
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this.clipHelper = clipHelpers[config.clip];
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if (this.clipHelper == null) throw "Invalid clip: " + config.clip;
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}
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AbstractInterpolator.prototype.getClippedInput = function(i) {
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if ((0 <= i && i < this.length)) {
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return this.array[i];
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} else {
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return this.clipHelper(i);
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}
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};
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AbstractInterpolator.prototype.clipHelperClamp = function(i) {
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return this.array[clipClamp(i, this.length)];
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};
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AbstractInterpolator.prototype.clipHelperZero = function(i) {
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return 0;
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};
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AbstractInterpolator.prototype.clipHelperPeriodic = function(i) {
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return this.array[clipPeriodic(i, this.length)];
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};
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AbstractInterpolator.prototype.clipHelperMirror = function(i) {
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return this.array[clipMirror(i, this.length)];
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};
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AbstractInterpolator.prototype.interpolate = function(t) {
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throw 'Subclasses of AbstractInterpolator must override the interpolate() method.';
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};
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return AbstractInterpolator;
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})();
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NearestInterpolator = (function(_super) {
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__extends(NearestInterpolator, _super);
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function NearestInterpolator() {
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NearestInterpolator.__super__.constructor.apply(this, arguments);
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}
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NearestInterpolator.prototype.interpolate = function(t) {
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return this.getClippedInput(Math.round(t));
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};
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return NearestInterpolator;
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})(AbstractInterpolator);
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LinearInterpolator = (function(_super) {
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__extends(LinearInterpolator, _super);
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function LinearInterpolator() {
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LinearInterpolator.__super__.constructor.apply(this, arguments);
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}
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LinearInterpolator.prototype.interpolate = function(t) {
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var a, b, k;
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k = Math.floor(t);
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a = this.getClippedInput(k);
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b = this.getClippedInput(k + 1);
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t -= k;
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return (1 - t) * a + t * b;
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};
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return LinearInterpolator;
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})(AbstractInterpolator);
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CubicInterpolator = (function(_super) {
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__extends(CubicInterpolator, _super);
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function CubicInterpolator(array, config) {
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this.tangentFactor = 1 - Math.max(0, Math.min(1, config.cubicTension));
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CubicInterpolator.__super__.constructor.apply(this, arguments);
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}
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CubicInterpolator.prototype.getTangent = function(k) {
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return this.tangentFactor * (this.getClippedInput(k + 1) - this.getClippedInput(k - 1)) / 2;
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};
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CubicInterpolator.prototype.interpolate = function(t) {
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var k, m, p, t2, t3;
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k = Math.floor(t);
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m = [this.getTangent(k), this.getTangent(k + 1)];
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p = [this.getClippedInput(k), this.getClippedInput(k + 1)];
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t -= k;
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t2 = t * t;
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t3 = t * t2;
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return (2 * t3 - 3 * t2 + 1) * p[0] + (t3 - 2 * t2 + t) * m[0] + (-2 * t3 + 3 * t2) * p[1] + (t3 - t2) * m[1];
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};
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return CubicInterpolator;
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})(AbstractInterpolator);
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sin = Math.sin, PI = Math.PI;
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sinc = function(x) {
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if (x === 0) {
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return 1;
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} else {
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return sin(PI * x) / (PI * x);
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}
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};
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makeLanczosWindow = function(a) {
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return function(x) {
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return sinc(x / a);
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};
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};
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makeSincKernel = function(window) {
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return function(x) {
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return sinc(x) * window(x);
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};
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};
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SincFilterInterpolator = (function(_super) {
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__extends(SincFilterInterpolator, _super);
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function SincFilterInterpolator(array, config) {
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var window;
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SincFilterInterpolator.__super__.constructor.apply(this, arguments);
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this.a = config.sincFilterSize;
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window = config.sincWindow;
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if (window == null) throw 'No sincWindow provided';
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this.kernel = makeSincKernel(window);
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}
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SincFilterInterpolator.prototype.interpolate = function(t) {
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var k, n, sum, _ref, _ref2;
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k = Math.floor(t);
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sum = 0;
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for (n = _ref = k - this.a + 1, _ref2 = k + this.a; _ref <= _ref2 ? n <= _ref2 : n >= _ref2; _ref <= _ref2 ? n++ : n--) {
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sum += this.kernel(t - n) * this.getClippedInput(n);
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}
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return sum;
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};
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return SincFilterInterpolator;
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})(AbstractInterpolator);
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getColumn = function(arr, i) {
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var row, _i, _len, _results;
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_results = [];
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for (_i = 0, _len = arr.length; _i < _len; _i++) {
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row = arr[_i];
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_results.push(row[i]);
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}
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return _results;
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};
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makeScaledFunction = function(f, baseScale, scaleRange) {
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var scaleFactor, translation;
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if (scaleRange.join === '0,1') {
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return f;
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} else {
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scaleFactor = baseScale / (scaleRange[1] - scaleRange[0]);
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translation = scaleRange[0];
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return function(t) {
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return f(scaleFactor * (t - translation));
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};
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}
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};
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getType = function(x) {
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return Object.prototype.toString.call(x).slice('[object '.length, -1);
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};
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validateNumber = function(n) {
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if (isNaN(n)) throw 'NaN in Smooth() input';
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if (getType(n) !== 'Number') throw 'Non-number in Smooth() input';
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if (!isFinite(n)) throw 'Infinity in Smooth() input';
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};
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validateVector = function(v, dimension) {
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var n, _i, _len, _results;
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if (getType(v) !== 'Array') throw 'Non-vector in Smooth() input';
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if (v.length !== dimension) throw 'Inconsistent dimension in Smooth() input';
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_results = [];
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for (_i = 0, _len = v.length; _i < _len; _i++) {
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n = v[_i];
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_results.push(validateNumber(n));
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}
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return _results;
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};
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isValidNumber = function(n) {
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return (getType(n) === 'Number') && isFinite(n) && !isNaN(n);
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};
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normalizeScaleTo = function(s) {
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var invalidErr;
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invalidErr = "scaleTo param must be number or array of two numbers";
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switch (getType(s)) {
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case 'Number':
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if (!isValidNumber(s)) throw invalidErr;
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s = [0, s];
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break;
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case 'Array':
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if (s.length !== 2) throw invalidErr;
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if (!(isValidNumber(s[0]) && isValidNumber(s[1]))) throw invalidErr;
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break;
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default:
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throw invalidErr;
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}
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return s;
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};
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shallowCopy = function(obj) {
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var copy, k, v;
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copy = {};
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for (k in obj) {
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if (!__hasProp.call(obj, k)) continue;
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v = obj[k];
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copy[k] = v;
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}
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return copy;
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};
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Smooth = function(arr, config) {
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var baseScale, dataType, dimension, i, interpolator, interpolatorClass, interpolatorClasses, interpolators, k, n, scaleRange, smoothFunc, v;
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if (config == null) config = {};
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config = shallowCopy(config);
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if (config.scaleTo == null) config.scaleTo = config.period;
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if (config.sincFilterSize == null) {
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config.sincFilterSize = config.lanczosFilterSize;
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}
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for (k in defaultConfig) {
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if (!__hasProp.call(defaultConfig, k)) continue;
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v = defaultConfig[k];
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if (config[k] == null) config[k] = v;
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}
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interpolatorClasses = {
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nearest: NearestInterpolator,
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linear: LinearInterpolator,
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cubic: CubicInterpolator,
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lanczos: SincFilterInterpolator,
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sinc: SincFilterInterpolator
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};
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interpolatorClass = interpolatorClasses[config.method];
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if (interpolatorClass == null) throw "Invalid method: " + config.method;
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if (config.method === 'lanczos') {
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config.sincWindow = makeLanczosWindow(config.sincFilterSize);
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}
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if (arr.length < 2) throw 'Array must have at least two elements';
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dataType = getType(arr[0]);
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smoothFunc = (function() {
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var _i, _j, _len, _len2;
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switch (dataType) {
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case 'Number':
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if (Smooth.deepValidation) {
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for (_i = 0, _len = arr.length; _i < _len; _i++) {
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n = arr[_i];
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validateNumber(n);
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}
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}
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interpolator = new interpolatorClass(arr, config);
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return function(t) {
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return interpolator.interpolate(t);
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};
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case 'Array':
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dimension = arr[0].length;
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if (!dimension) throw 'Vectors must be non-empty';
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if (Smooth.deepValidation) {
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for (_j = 0, _len2 = arr.length; _j < _len2; _j++) {
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v = arr[_j];
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validateVector(v, dimension);
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}
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}
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interpolators = (function() {
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var _results;
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_results = [];
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for (i = 0; 0 <= dimension ? i < dimension : i > dimension; 0 <= dimension ? i++ : i--) {
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_results.push(new interpolatorClass(getColumn(arr, i), config));
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}
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return _results;
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})();
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return function(t) {
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var interpolator, _k, _len3, _results;
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_results = [];
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for (_k = 0, _len3 = interpolators.length; _k < _len3; _k++) {
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interpolator = interpolators[_k];
|
||
|
|
_results.push(interpolator.interpolate(t));
|
||
|
|
}
|
||
|
|
return _results;
|
||
|
|
};
|
||
|
|
default:
|
||
|
|
throw "Invalid element type: " + dataType;
|
||
|
|
}
|
||
|
|
})();
|
||
|
|
if (config.scaleTo) {
|
||
|
|
scaleRange = normalizeScaleTo(config.scaleTo);
|
||
|
|
if (config.clip === Smooth.CLIP_PERIODIC) {
|
||
|
|
baseScale = arr.length;
|
||
|
|
} else {
|
||
|
|
baseScale = arr.length - 1;
|
||
|
|
}
|
||
|
|
smoothFunc = makeScaledFunction(smoothFunc, baseScale, scaleRange);
|
||
|
|
}
|
||
|
|
return smoothFunc;
|
||
|
|
};
|
||
|
|
|
||
|
|
for (k in Enum) {
|
||
|
|
if (!__hasProp.call(Enum, k)) continue;
|
||
|
|
v = Enum[k];
|
||
|
|
Smooth[k] = v;
|
||
|
|
}
|
||
|
|
|
||
|
|
Smooth.deepValidation = true;
|
||
|
|
|
||
|
|
root = typeof exports !== "undefined" && exports !== null ? exports : window;
|
||
|
|
|
||
|
|
root.Smooth = Smooth;
|
||
|
|
|
||
|
|
}).call(this);
|