@poupe/material-color-utilities
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Algorithms and utilities that power the Material Design 3 (M3) color system, including choosing theme colors from images and creating tones of colors; all in a new color space.
51 lines • 1.83 kB
JavaScript
/**
* @license
* Copyright 2021 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import * as utils from '../utils/color_utils.js';
/**
* Provides conversions needed for K-Means quantization. Converting input to
* points, and converting the final state of the K-Means algorithm to colors.
*/
export class LabPointProvider {
/**
* Convert a color represented in ARGB to a 3-element array of L*a*b*
* coordinates of the color.
*/
fromInt(argb) {
return utils.labFromArgb(argb);
}
/**
* Convert a 3-element array to a color represented in ARGB.
*/
toInt(point) {
return utils.argbFromLab(point[0], point[1], point[2]);
}
/**
* Standard CIE 1976 delta E formula also takes the square root, unneeded
* here. This method is used by quantization algorithms to compare distance,
* and the relative ordering is the same, with or without a square root.
*
* This relatively minor optimization is helpful because this method is
* called at least once for each pixel in an image.
*/
distance(from, to) {
const dL = from[0] - to[0];
const dA = from[1] - to[1];
const dB = from[2] - to[2];
return dL * dL + dA * dA + dB * dB;
}
}
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