var MatrixStack = { 
matrixStack: null ,
currentMatrix: null ,
currentMatrixIndex: 0,
initMatrixStack: function (){ 
this.matrixStack = new Float32Array(6000); 
this.currentMatrix = new Float32Array([1, 0, 0, 1, 0, 0] ); 
this.currentMatrixIndex = 0; 
return this; 
} 
,
save: function (){ 
if (this.currentMatrixIndex >= _AN_Read_length('length', this.matrixStack)) { 
return this; 
} 
var matrixStack = this.matrixStack; 
var currentMatrix = this.currentMatrix; 
var currentMatrixIndex = this.currentMatrixIndex; 
this.currentMatrixIndex += 6; 
matrixStack[currentMatrixIndex + 0] = currentMatrix[0]; 
matrixStack[currentMatrixIndex + 1] = currentMatrix[1]; 
matrixStack[currentMatrixIndex + 2] = currentMatrix[2]; 
matrixStack[currentMatrixIndex + 3] = currentMatrix[3]; 
matrixStack[currentMatrixIndex + 4] = currentMatrix[4]; 
matrixStack[currentMatrixIndex + 5] = currentMatrix[5]; 
return this; 
} 
,
restore: function (){ 
if (this.currentMatrixIndex <= 0) { 
return this; 
} 
this.currentMatrixIndex -= 6; 
var matrixStack = this.matrixStack; 
var currentMatrix = this.currentMatrix; 
var currentMatrixIndex = this.currentMatrixIndex; 
currentMatrix[0] = matrixStack[currentMatrixIndex + 0]; 
currentMatrix[1] = matrixStack[currentMatrixIndex + 1]; 
currentMatrix[2] = matrixStack[currentMatrixIndex + 2]; 
currentMatrix[3] = matrixStack[currentMatrixIndex + 3]; 
currentMatrix[4] = matrixStack[currentMatrixIndex + 4]; 
currentMatrix[5] = matrixStack[currentMatrixIndex + 5]; 
return this; 
} 
,
loadIdentity: function (){ 
this.setTransform(1, 0, 0, 1, 0, 0); 
return this; 
} 
,
transform: function (a, b, c, d, tx, ty){ 
var currentMatrix = this.currentMatrix; 
var m0 = currentMatrix[0]; 
var m1 = currentMatrix[1]; 
var m2 = currentMatrix[2]; 
var m3 = currentMatrix[3]; 
var m4 = currentMatrix[4]; 
var m5 = currentMatrix[5]; 
currentMatrix[0] = m0 * a + m2 * b; 
currentMatrix[1] = m1 * a + m3 * b; 
currentMatrix[2] = m0 * c + m2 * d; 
currentMatrix[3] = m1 * c + m3 * d; 
currentMatrix[4] = m0 * tx + m2 * ty + m4; 
currentMatrix[5] = m1 * tx + m3 * ty + m5; 
return this; 
} 
,
setTransform: function (a, b, c, d, tx, ty){ 
var currentMatrix = this.currentMatrix; 
currentMatrix[0] = a; 
currentMatrix[1] = b; 
currentMatrix[2] = c; 
currentMatrix[3] = d; 
currentMatrix[4] = tx; 
currentMatrix[5] = ty; 
return this; 
} 
,
translate: function (x, y){ 
var currentMatrix = this.currentMatrix; 
var m0 = currentMatrix[0]; 
var m1 = currentMatrix[1]; 
var m2 = currentMatrix[2]; 
var m3 = currentMatrix[3]; 
var m4 = currentMatrix[4]; 
var m5 = currentMatrix[5]; 
currentMatrix[4] = m0 * x + m2 * y + m4; 
currentMatrix[5] = m1 * x + m3 * y + m5; 
return this; 
} 
,
scale: function (x, y){ 
var currentMatrix = this.currentMatrix; 
var m0 = currentMatrix[0]; 
var m1 = currentMatrix[1]; 
var m2 = currentMatrix[2]; 
var m3 = currentMatrix[3]; 
currentMatrix[0] = m0 * x; 
currentMatrix[1] = m1 * x; 
currentMatrix[2] = m2 * y; 
currentMatrix[3] = m3 * y; 
return this; 
} 
,
rotate: function (t){ 
var currentMatrix = this.currentMatrix; 
var m0 = currentMatrix[0]; 
var m1 = currentMatrix[1]; 
var m2 = currentMatrix[2]; 
var m3 = currentMatrix[3]; 
var st = Math.sin(t); 
var ct = Math.cos(t); 
currentMatrix[0] = m0 * ct + m2 * st; 
currentMatrix[1] = m1 * ct + m3 * st; 
currentMatrix[2] = m0 * - st + m2 * ct; 
currentMatrix[3] = m1 * - st + m3 * ct; 
return this; 
} 
}
; 
module.exports = MatrixStack;