scaleAndTranslate(sx, sy, tx, ty) {
        const a = this.values;
        const a00 = a[0];
        const a01 = a[1];
        const a02 = a[2];
        const a10 = a[3];
        const a11 = a[4];
        const a12 = a[5];
        return new Mat3([
            sx * a00,
            sx * a01,
            sx * a02,
            sy * a10,
            sy * a11,
            sy * a12,
            tx * a00 + ty * a10,
            tx * a01 + ty * a11,
            tx * a02 + ty * a12,
        ]);
    }
Scaling & translation only changes certain values, no need to compute full matrix multiplication.
@memberof OpenSeadragon.Mat3
@returns {OpenSeadragon.Mat3} The result of matrix multiplication