@future-grid/fgp-graph/src/services/colorService.ts

fgp-graph is a chart lib based on Dygraphs

export const RGB_COLOR_REGEX = /\((\d+),\s*(\d+),\s*(\d+)(,\s*(\d*.\d*))?\)/;

export class FgpColor {
    public r: number = 0;
    public g: number = 0;
    public b: number = 0;
    public a: number = 1;

    constructor()
    constructor(r?: string)
    constructor(r?: string | number, g?: number, b?: number)
    constructor(r?: string | number, g?: number, b?: number, a?: number) {
        if (typeof r === 'string') {
            r = r.trim();
            if (r.indexOf('#') === 0) {
                r = r.substr(r.indexOf('#') + 1);
                this.r = parseInt(r.substr(0, 2), 16);
                this.g = parseInt(r.substr(2, 2), 16);
                this.b = parseInt(r.substr(4, 2), 16);
            } else if (r.indexOf('rgb') === 0) {
                const res: RegExpExecArray | null = RGB_COLOR_REGEX.exec(r);
                if (res) {
                    this.r = parseInt(res[1], 10);
                    this.g = parseInt(res[2], 10);
                    this.b = parseInt(res[3], 10);
                    this.a = res[5] ? parseFloat(res[5]) : 1;
                }
            }
        } else {
            this.r = r ? r : 0;
            this.g = g ? g : 0;
            this.b = b ? b : 0;
            this.a = a || 1;
        }
    }

    toHex() {
        return '#' + this.r.toString(16) + this.g.toString(16) + this.b.toString(16);
    }

    toRgb() {
        return `rgb(${this.r}, ${this.g}, ${this.b})`;
    }

    toRgba() {
        return `rgba(${this.r}, ${this.g}, ${this.b}, ${this.a})`;
    }

    toRgbWithAlpha(a: number) {
        return `rgba(${this.r}, ${this.g}, ${this.b}, ${a})`;
    }
}


export function hsvToRGB(hue: number, saturation: number, value: number) {
    let red = 0;
    let green = 0;
    let blue = 0;
    if (saturation === 0) {
        red = value;
        green = value;
        blue = value;
    } else {
        let i = Math.floor(hue * 6);
        let f = (hue * 6) - i;
        let p = value * (1 - saturation);
        let q = value * (1 - (saturation * f));
        let t = value * (1 - (saturation * (1 - f)));
        switch (i) {
            case 1:
                red = q;
                green = value;
                blue = p;
                break;
            case 2:
                red = p;
                green = value;
                blue = t;
                break;
            case 3:
                red = p;
                green = q;
                blue = value;
                break;
            case 4:
                red = t;
                green = p;
                blue = value;
                break;
            case 5:
                red = value;
                green = p;
                blue = q;
                break;
            case 6: // fall through
            case 0:
                red = value;
                green = t;
                blue = p;
                break;
        }
    }
    red = Math.floor(255 * red + 0.5);
    green = Math.floor(255 * green + 0.5);
    blue = Math.floor(255 * blue + 0.5);
    return 'rgb(' + red + ',' + green + ',' + blue + ')';
}