Function Mat33TimesVec

jni/stasm/misc.cpp:416–431

// bottom row of a homogeneous mat is constant and is ignored here).

static void Mat33TimesVec(
    VEC&       v,   // io: two element vector
    const MAT& mat) // in: three column matrix
{
    CV_DbgAssert(v.rows == 1 && v.cols == 2);
    CV_DbgAssert(mat.rows >= 2 && mat.cols == 3);
    CV_Assert(mat.isContinuous());

    const double* const data = Buf(mat);

    const double x = v(0, 0);
    const double y = v(0, 1);

    v(0, 0) = data[0] * x + data[1] * y + data[2];
    v(0, 1) = data[3] * x + data[4] * y + data[5];
}

// Transform shape by multiplying it by a homogeneous alignment_mat.
// alignment_mat can be 3x2 or 2x2 (since the bottom row of a homogeneous mat