Avoid another Eigen->NumPy conversion

Author: QuLogic

lib/matplotlib/tests/test_transforms.py

@@ -778,8 +778,8 @@ def test_line_extent_compound_coords2(self):
         trans = mtransforms.blended_transform_factory(
             ax.transAxes, mtransforms.Affine2D().scale(10) + ax.transData)
         ax.plot([0.1, 1.2, 0.8], [35, -5, 18], transform=trans)
-        assert_array_equal(ax.dataLim.get_points(),
-                           np.array([[np.inf, -50.], [-np.inf, 350.]]))
+        assert_array_almost_equal(ax.dataLim.get_points(),
+                                  np.array([[np.inf, -50.], [-np.inf, 350.]]))
 
     def test_line_extents_affine(self):
         ax = plt.axes()

lib/matplotlib/transforms.py

@@ -42,7 +42,6 @@
 import math
 
 import numpy as np
-from numpy.linalg import inv
 
 from matplotlib import _api, _eigen
 from matplotlib._path import count_bboxes_overlapping_bbox
@@ -1902,11 +1901,11 @@ def transform_affine(self, values):
     def inverted(self):
         # docstring inherited
         if self._inverted is None or self._invalid:
-            mtx = self.get_matrix()
+            mtx = self._get_eigen_matrix()
             shorthand_name = None
             if self._shorthand_name:
-                shorthand_name = '(%s)-1' % self._shorthand_name
-            self._inverted = Affine2D(inv(mtx), shorthand_name=shorthand_name)
+                shorthand_name = '({self._shorthand_name})-1'
+            self._inverted = Affine2D(mtx.inverse(), shorthand_name=shorthand_name)
             self._invalid = 0
         return self._inverted
 

src/_eigen.cpp

@@ -12,6 +12,10 @@ PYBIND11_MODULE(_eigen, m) {
         .def(py::init([]() {
             return Eigen::Affine2d::Identity();
         }))
+        .def(py::init([](const Eigen::Affine2d& matrix) {
+            return Eigen::Affine2d(matrix);
+        }),
+        "matrix"_a.none(false))
         .def(py::init([](const Eigen::Matrix3d& matrix) {
             return Eigen::Affine2d(matrix);
         }),
@@ -76,6 +80,11 @@ PYBIND11_MODULE(_eigen, m) {
         }, "other"_a,
         "Combines two transforms.")
 
+        .def("inverse", [](const Eigen::Affine2d& self) {
+            return self.inverse();
+        },
+        "Calculate the inverse of this transformation.")
+
         .def("remove_translate", [](Eigen::Affine2d& self) {
             self(0, 2) = 0.0;
             self(1, 2) = 0.0;