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Diffstat (limited to 'src/2geom/affine.cpp')
| -rw-r--r-- | src/2geom/affine.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/2geom/affine.cpp b/src/2geom/affine.cpp index 2a1f18d77..c31b9ba90 100644 --- a/src/2geom/affine.cpp +++ b/src/2geom/affine.cpp @@ -410,6 +410,9 @@ Affine &Affine::operator*=(Affine const &o) { } //TODO: What's this!?! +/** Given a matrix m such that unit_circle = m*x, this returns the + * quadratic form x*A*x = 1. + * @relates Affine */ Affine elliptic_quadratic_form(Affine const &m) { double od = m[0] * m[1] + m[2] * m[3]; Affine ret (m[0]*m[0] + m[1]*m[1], od, @@ -469,6 +472,15 @@ Eigen::Eigen(double m[2][2]) { vectors[i] = Point(0,0); } +/** @brief Nearness predicate for affine transforms + * @returns True if all entries of matrices are within eps of each other */ +bool are_near(Affine const &a, Affine const &b, Coord eps) +{ + return are_near(a[0], b[0], eps) && are_near(a[1], b[1], eps) && + are_near(a[2], b[2], eps) && are_near(a[3], b[3], eps) && + are_near(a[4], b[4], eps) && are_near(a[5], b[5], eps); +} + } //namespace Geom /* |