index.js

var Matrix = function() {
    this.reset();
};
Matrix.prototype.reset = function() {
    this.m = [1, 0, 0, 1, 0, 0];
    return this;
};
Matrix.prototype.multiply = function(matrix) {
    var m11 = this.m[0] * matrix.m[0] + this.m[2] * matrix.m[1],
        m12 = this.m[1] * matrix.m[0] + this.m[3] * matrix.m[1],
        m21 = this.m[0] * matrix.m[2] + this.m[2] * matrix.m[3],
        m22 = this.m[1] * matrix.m[2] + this.m[3] * matrix.m[3];

    var dx = this.m[0] * matrix.m[4] + this.m[2] * matrix.m[5] + this.m[4],
        dy = this.m[1] * matrix.m[4] + this.m[3] * matrix.m[5] + this.m[5];
    this.m[0] = m11;
    this.m[1] = m12;
    this.m[2] = m21;
    this.m[3] = m22;
    this.m[4] = dx;
    this.m[5] = dy;
    return this;
};
Matrix.prototype.inverse = function() {
    var inv = new Matrix();
    inv.m = this.m.slice(0);
    var d = 1 / (inv.m[0] * inv.m[3] - inv.m[1] * inv.m[2]),
        m0 = inv.m[3] * d,
        m1 = -inv.m[1] * d,
        m2 = -inv.m[2] * d,
        m3 = inv.m[0] * d,
        m4 = d * (inv.m[2] * inv.m[5] - inv.m[3] * inv.m[4]),
        m5 = d * (inv.m[1] * inv.m[4] - inv.m[0] * inv.m[5]);
    inv.m[0] = m0;
    inv.m[1] = m1;
    inv.m[2] = m2;
    inv.m[3] = m3;
    inv.m[4] = m4;
    inv.m[5] = m5;
    return inv;
};
Matrix.prototype.rotate = function(rad) {
    var c = Math.cos(rad),
        s = Math.sin(rad),
        m11 = this.m[0] * c + this.m[2] * s,
        m12 = this.m[1] * c + this.m[3] * s,
        m21 = this.m[0] * -s + this.m[2] * c,
        m22 = this.m[1] * -s + this.m[3] * c;
    this.m[0] = m11;
    this.m[1] = m12;
    this.m[2] = m21;
    this.m[3] = m22;
    return this;
};
Matrix.prototype.translate = function(x, y) {
    this.m[4] += this.m[0] * x + this.m[2] * y;
    this.m[5] += this.m[1] * x + this.m[3] * y;
    return this;
};
Matrix.prototype.scale = function(sx, sy) {
    this.m[0] *= sx;
    this.m[1] *= sx;
    this.m[2] *= sy;
    this.m[3] *= sy;
    return this;
};
Matrix.prototype.transformPoint = function(px, py) {
    var x = px,
        y = py;
    px = x * this.m[0] + y * this.m[2] + this.m[4];
    py = x * this.m[1] + y * this.m[3] + this.m[5];
    return [px, py];
};
Matrix.prototype.transformVector = function(px, py) {
    var x = px,
        y = py;
    px = x * this.m[0] + y * this.m[2];
    py = x * this.m[1] + y * this.m[3];
    return [px, py];
};
if(typeof module !== "undefined") {
    module.exports = Matrix;
}
else {
    window.Matrix = Matrix;
}