/
euclidean.ts
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/
euclidean.ts
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/**
* @preserve
* Copyright 2015-2018 Igor Bezkrovnyi
* All rights reserved. (MIT Licensed)
*
* euclidean.ts - part of Image Quantization Library
*/
import { AbstractDistanceCalculator } from './distanceCalculator';
import { Y } from '../constants/bt709';
/**
* Euclidean color distance
*/
export abstract class AbstractEuclidean extends AbstractDistanceCalculator {
protected _kR!: number;
protected _kG!: number;
protected _kB!: number;
protected _kA!: number;
calculateRaw(
r1: number,
g1: number,
b1: number,
a1: number,
r2: number,
g2: number,
b2: number,
a2: number,
) {
const dR = r2 - r1;
const dG = g2 - g1;
const dB = b2 - b1;
const dA = a2 - a1;
return Math.sqrt(
this._kR * dR * dR +
this._kG * dG * dG +
this._kB * dB * dB +
this._kA * dA * dA,
);
}
}
export class Euclidean extends AbstractEuclidean {
protected _setDefaults() {
this._kR = 1;
this._kG = 1;
this._kB = 1;
this._kA = 1;
}
}
/**
* Euclidean color distance (RGBQuant modification w Alpha)
*/
export class EuclideanBT709 extends AbstractEuclidean {
protected _setDefaults() {
this._kR = Y.RED;
this._kG = Y.GREEN;
this._kB = Y.BLUE;
// TODO: what is the best coefficient below?
this._kA = 1;
}
}
/**
* Euclidean color distance (RGBQuant modification w/o Alpha)
*/
export class EuclideanBT709NoAlpha extends AbstractEuclidean {
protected _setDefaults() {
this._kR = Y.RED;
this._kG = Y.GREEN;
this._kB = Y.BLUE;
this._kA = 0;
}
}