ontRgba) => {
                        const alpha = frontRgba[3] + 1;
                        const invAlpha = 256 - frontRgba[3];
                        return [
                            (alpha * frontRgba[0] + invAlpha * backRgba[0]) >> 8,
                            (alpha * frontRgba[1] + invAlpha * backRgba[1]) >> 8,
                            (alpha * frontRgba[2] + invAlpha * backRgba[2]) >> 8,
                            255
                        ];
                    };

                   