@giro3d/giro3d/src/utils/ColorUtils.ts

A JS/WebGL framework for 3D geospatial data visualization

/*
 * Copyright (c) 2015-2018, IGN France.
 * Copyright (c) 2018-2026, Giro3D team.
 * SPDX-License-Identifier: MIT
 */

import type { ColorRepresentation } from 'three';

import { Color } from 'three';

import { isColor } from './predicates';

// See https://www.codeproject.com/Articles/16565/Determining-Ideal-Text-Color-Based-on-Specified-Ba
/**
 * Returns a hex color (including the leading #) that contrasts with the input color.
 */
export function getContrastColor(color: ColorRepresentation): string {
    const c = isColor(color) ? color : new Color(color);
    // Find a text color with enough contrast from the background color
    const nThreshold = 105 / 255;
    const bgDelta = c.r * 0.299 + c.g * 0.587 + c.b * 0.114;

    return 1 - bgDelta < nThreshold ? '#000000' : '#ffffff';
}