void GfxState::concatCTM(double a, double b, double c, double d, double e, double f)
{
    double a1 = ctm[0];
    double b1 = ctm[1];
    double c1 = ctm[2];
    double d1 = ctm[3];

    ctm[0] = a * a1 + b * c1;
    ctm[1] = a * b1 + b * d1;
    ctm[2] = c * a1 + d * c1;
    ctm[3] = c * b1 + d * d1;
    ctm[4] = e * a1 + f * c1 + ctm[4];
    ctm[5] = e * b1 + f * d1 + ctm[5];
}
Unknown