nystudio107 / craft-webperf

export default class TriColorBlend {

    constructor(clr1 = '#00C800', clr2 = '#FFFF00', clr3 = '#C80000')

    {

        this.clr1 = this.HexToRGB(clr1);

        this.clr2 = this.HexToRGB(clr2);

        this.clr3 = this.HexToRGB(clr3);

    }

    RGBToHex(r, g, b)

    {

        let bin = r << 16 | g << 8 | b;

        return (function (h) {

            return new Array(7 - h.length).join("0") + h

        })(bin.toString(16).toUpperCase())

    }

    HexToRGB(hex)

    {

        let result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);

        return result ? {

            r: parseInt(result[1], 16),

            g: parseInt(result[2], 16),

            b: parseInt(result[3], 16)

        } : null;

    }

    colorFromPercentage(val)

    {

        let startColor = this.clr1;

        let endColor = this.clr2;

        if (val >= 50) {

            startColor = this.clr2;

            endColor = this.clr3;

            val = val - 50;

        }

        const multiplier = (val / 50);

        const r = Math.round(startColor.r + multiplier * (endColor.r - startColor.r));

        const g = Math.round(startColor.g + multiplier * (endColor.g - startColor.g));

        const b = Math.round(startColor.b + multiplier * (endColor.b - startColor.b));

        return '#' + this.RGBToHex(r,g,b);

    }

}