/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview A one dimensional linear interpolator.
*/
goog.provide('goog.math.interpolator.Linear1');
goog.require('goog.array');
goog.require('goog.asserts');
goog.require('goog.math');
goog.require('goog.math.interpolator.Interpolator1');
/**
* A one dimensional linear interpolator.
* @implements {goog.math.interpolator.Interpolator1}
* @constructor
* @final
*/
goog.math.interpolator.Linear1 = function() {
'use strict';
/**
* The abscissa of the data points.
* @type {!Array<number>}
* @private
*/
this.x_ = [];
/**
* The ordinate of the data points.
* @type {!Array<number>}
* @private
*/
this.y_ = [];
};
/** @override */
goog.math.interpolator.Linear1.prototype.setData = function(x, y) {
'use strict';
goog.asserts.assert(
x.length == y.length,
'input arrays to setData should have the same length');
if (x.length == 1) {
this.x_ = [x[0], x[0] + 1];
this.y_ = [y[0], y[0]];
} else {
this.x_ = x.slice();
this.y_ = y.slice();
}
};
/** @override */
goog.math.interpolator.Linear1.prototype.interpolate = function(x) {
'use strict';
let pos = goog.array.binarySearch(this.x_, x);
if (pos < 0) {
pos = -pos - 2;
}
pos = goog.math.clamp(pos, 0, this.x_.length - 2);
const progress = (x - this.x_[pos]) / (this.x_[pos + 1] - this.x_[pos]);
return goog.math.lerp(this.y_[pos], this.y_[pos + 1], progress);
};
/** @override */
goog.math.interpolator.Linear1.prototype.getInverse = function() {
'use strict';
const interpolator = new goog.math.interpolator.Linear1();
interpolator.setData(this.y_, this.x_);
return interpolator;
};