Merge pull request #777 from jabooth/3drots

convienience constructors for 3D rotations

menpo/transform/homogeneous/affine.py

@@ -62,8 +62,8 @@ def init_from_2d_shear(cls, phi, psi, degrees=True):
             A 2D shear transform.
         """
         if degrees:
-            phi = phi * np.pi / 180.
-            psi = psi * np.pi / 180.
+            phi = np.deg2rad(phi)
+            psi = np.deg2rad(psi)
         # Create shear matrix
         h_matrix = np.eye(3)
         h_matrix[0, 1] = np.tan(phi)

menpo/transform/homogeneous/rotation.py

@@ -127,8 +127,7 @@ def init_from_2d_ccw_angle(cls, theta, degrees=True):
             A 2D rotation transform.
         """
         if degrees:
-            # convert to radians
-            theta = theta * np.pi / 180.0
+            theta = np.deg2rad(theta)
         return Rotation(np.array([[np.cos(theta), -np.sin(theta)],
                                   [np.sin(theta),  np.cos(theta)]]),
                         skip_checks=True)
@@ -151,6 +150,81 @@ def init_3d_from_quaternion(cls, q):
         r = cls.init_identity(n_dims=3)
         return r.from_vector(q)
 
+    @classmethod
+    def init_from_3d_ccw_angle_around_x(cls, theta, degrees=True):
+        r"""
+        Convenience constructor for 3D CCW rotations around the x axis
+
+        Parameters
+        ----------
+        theta : `float`
+            The angle of rotation about the origin
+        degrees : `bool`, optional
+            If ``True`` theta is interpreted as a degree. If ``False``, theta is
+            interpreted as radians.
+
+        Returns
+        -------
+        rotation : :map:`Rotation`
+            A 3D rotation transform.
+        """
+        if degrees:
+            theta = np.deg2rad(theta)
+        return Rotation(np.array([[ 1,             0,              0],
+                                  [ 0, np.cos(theta), -np.sin(theta)],
+                                  [ 0, np.sin(theta), np.cos(theta)]]),
+                        skip_checks=True)
+
+    @classmethod
+    def init_from_3d_ccw_angle_around_y(cls, theta, degrees=True):
+        r"""
+        Convenience constructor for 3D CCW rotations around the y axis
+
+        Parameters
+        ----------
+        theta : `float`
+            The angle of rotation about the origin
+        degrees : `bool`, optional
+            If ``True`` theta is interpreted as a degree. If ``False``, theta is
+            interpreted as radians.
+
+        Returns
+        -------
+        rotation : :map:`Rotation`
+            A 3D rotation transform.
+        """
+        if degrees:
+            theta = np.deg2rad(theta)
+        return Rotation(np.array([[ np.cos(theta), 0, np.sin(theta)],
+                                  [             0, 1,             0],
+                                  [-np.sin(theta), 0, np.cos(theta)]]),
+                        skip_checks=True)
+
+    @classmethod
+    def init_from_3d_ccw_angle_around_z(cls, theta, degrees=True):
+        r"""
+        Convenience constructor for 3D CCW rotations around the z axis
+
+        Parameters
+        ----------
+        theta : `float`
+            The angle of rotation about the origin
+        degrees : `bool`, optional
+            If ``True`` theta is interpreted as a degree. If ``False``, theta is
+            interpreted as radians.
+
+        Returns
+        -------
+        rotation : :map:`Rotation`
+            A 3D rotation transform.
+        """
+        if degrees:
+            theta = np.deg2rad(theta)
+        return Rotation(np.array([[ np.cos(theta), -np.sin(theta), 0],
+                                  [ np.sin(theta),  np.cos(theta), 0],
+                                  [             0,              0, 1]]),
+                        skip_checks=True)
+
     @property
     def rotation_matrix(self):
         r"""
@@ -184,12 +258,12 @@ def set_rotation_matrix(self, value, skip_checks=False):
         self._h_matrix[:-1, :-1] = value
 
     def _transform_str(self):
-        axis, rad_angle_of_rotation = self.axis_and_angle_of_rotation()
+        axis, radians_of_rotation = self.axis_and_angle_of_rotation()
         if axis is None:
             return "NO OP"
-        angle_of_rot = (rad_angle_of_rotation * 180.0) / np.pi
+        degrees_of_rotation = np.rad2deg(radians_of_rotation)
         message = ('CCW Rotation of {:.1f} degrees '
-                   'about {}'.format(angle_of_rot,axis))
+                   'about {}'.format(degrees_of_rotation, axis))
         return message
 
     def axis_and_angle_of_rotation(self):

menpo/transform/test/h_rotation_test.py

@@ -105,3 +105,21 @@ def test_rotation2d_identity():
 
 def test_rotation3d_identity():
     assert_allclose(Rotation.init_identity(3).h_matrix, np.eye(4))
+
+
+def test_rotation3d_init_from_3d_ccw_angle_around_x():
+    assert_allclose(
+        Rotation.init_from_3d_ccw_angle_around_x(90).apply(np.array([0, 0, 1])),
+        np.array([0, -1, 0]), atol=1e-6)
+
+
+def test_rotation3d_init_from_3d_ccw_angle_around_y():
+    assert_allclose(
+        Rotation.init_from_3d_ccw_angle_around_y(90).apply(np.array([0, 0, 1])),
+        np.array([1, 0, 0]), atol=1e-6)
+
+
+def test_rotation3d_init_from_3d_ccw_angle_around_z():
+    assert_allclose(
+        Rotation.init_from_3d_ccw_angle_around_z(90).apply(np.array([0, 1, 0])),
+        np.array([-1, 0, 0]), atol=1e-6)