# $Id$
# simple matrix class for affine transforms

import math

##
# Simple 3x3 matrix class.  This class is useful for calculating affine
# transforms for PIL and aggdraw, and not much else.

class Matrix:

    def __init__(self, matrix=None):
        if matrix is None:
            self.setidentity()
        else:
            self.setmatrix(matrix)

    def setidentity(self):
        self.a = 1; self.b = 0; self.c = 0
        self.d = 0; self.e = 1; self.f = 0

    def setmatrix(self, m):
        if isinstance(m, Matrix):
            self.a = m.a; self.b = m.b; self.c = m.c
            self.d = m.d; self.e = m.e; self.f = m.f
        else:
            # assume it's a matrix
            self.a = m[0]; self.b = m[1]; self.c = m[2]
            self.d = m[3]; self.e = m[4]; self.f = m[5]

    def getmatrix(self):
        return self.a, self.b, self.c, self.d, self.e, self.f

    def transform(self, x, y):
        X = self.a*x + self.b*y + self.c
        Y = self.d*x + self.e*y + self.f
        return X, Y

    def multiply(self, a, b, c, d, e, f):
        _a=self.a; _b=self.b; _c=self.c
        _d=self.d; _e=self.e; _f=self.f
        self.a = _a*a + _d*b;
        self.b = _b*a + _e*b;
        self.c = _c*a + _f*b + c;
        self.d = _a*d + _d*e;
        self.e = _b*d + _e*e;
        self.f = _c*d + _f*e + f;

    def rotate(self, a):
        a = a * math.pi / 180.0
        c = math.cos(a)
        s = math.sin(a)
        self.multiply(c, -s, 0, s, c, 0)

    def scale(self, x, y):
        self.multiply(x, 0, 0, 0, y, 0)

    def translate(self, x, y):
        self.multiply(1, 0, x, 0, 1, y)