3D plot roll angle flake8, tests, and whats new

scottshambaugh · scottshambaugh · commit e1770bc6e284 · 2021-10-22T13:42:05.000-06:00
diff --git a/doc/users/next_whats_new/3d_plot_roll_angle.rst b/doc/users/next_whats_new/3d_plot_roll_angle.rst
@@ -0,0 +1,21 @@
+3D plots have now have a 3rd "roll" viewing angle
+-------------------------------------------------
+
+3D plots can now be viewed from any orientation with the addition of a 3rd roll
+angle, which rotates the plot about the viewing axis. Interactive rotation
+using the mouse still only controls elevation and azimuth, meaning that this
+feature is only really relevant to users who want to create more complex camera
+angles programmatically. The default roll angle of 0 is backwards-compatible 
+with existing 3D plots. 
+
+.. plot::
+    :include-source: true
+    
+    from mpl_toolkits.mplot3d import axes3d
+    import matplotlib.pyplot as plt
+    fig = plt.figure()
+    ax = fig.add_subplot(projection='3d')
+    X, Y, Z = axes3d.get_test_data(0.05)
+    ax.plot_wireframe(X, Y, Z, rstride=10, cstride=10)
+    ax.view_init(elev=0, azim=0, roll=30)
+    plt.show()
diff --git a/lib/mpl_toolkits/mplot3d/axes3d.py b/lib/mpl_toolkits/mplot3d/axes3d.py
@@ -1270,7 +1270,7 @@ def _on_move(self, event):
             roll = np.deg2rad(self.roll)
             if dx == 0 and dy == 0:
                 return
-            delev =  (dy/h)*180*np.cos(roll) + (dx/w)*180*np.sin(roll)
+            delev = +(dy/h)*180*np.cos(roll) + (dx/w)*180*np.sin(roll)
             dazim = -(dy/h)*180*np.sin(roll) + (dx/w)*180*np.cos(roll)
             self.elev = art3d._norm_angle(self.elev - delev)
             self.azim = art3d._norm_angle(self.azim - dazim)
diff --git a/lib/mpl_toolkits/mplot3d/proj3d.py b/lib/mpl_toolkits/mplot3d/proj3d.py
@@ -52,7 +52,9 @@ def world_transformation(xmin, xmax,
 
 
 def rotation_about_vector(v, angle):
-    '''Produce a rotation matrix for an angle in radians about a vector.'''
+    """
+    Produce a rotation matrix for an angle in radians about a vector.
+    """
     v /= np.linalg.norm(v)
     s = np.sin(angle)
     c = np.cos(angle)
@@ -61,26 +63,27 @@ def rotation_about_vector(v, angle):
     R = np.array([
         [t*v[0]*v[0] + c,      t*v[0]*v[1] - v[2]*s, t*v[0]*v[2] + v[1]*s],
         [t*v[1]*v[0] + v[2]*s, t*v[1]*v[1] + c,      t*v[1]*v[2] - v[0]*s],
-        [t*v[2]*v[0] - v[1]*s, t*v[2]*v[1] + v[0]*s, t*v[2]*v[2] + c     ]])
+        [t*v[2]*v[0] - v[1]*s, t*v[2]*v[1] + v[0]*s, t*v[2]*v[2] + c]])
 
     return R
 
 
 def view_transformation(E, R, V, roll):
     n = (E - R)
-    n /= np.linalg.norm(n)
+    n = n/np.linalg.norm(n)
     u = np.cross(V, n)
-    u /= np.linalg.norm(u)
+    u = u/np.linalg.norm(u)
     v = np.cross(n, u)
+    v = v/np.linalg.norm(v)
 
     Rroll = rotation_about_vector(n, roll)
     u = np.dot(Rroll, u)
     v = np.dot(Rroll, v)
 
     Mr = np.diag([1.] * 4)
     Mt = np.diag([1.] * 4)
-    Mr[:3,:3] = u, v, n
-    Mt[:3,-1] = -E
+    Mr[:3, :3] = [u, v, n]
+    Mt[:3, -1] = -E
 
     return np.dot(Mr, Mt)
 
diff --git a/lib/mpl_toolkits/tests/baseline_images/test_mplot3d/bar3d_shaded.png b/lib/mpl_toolkits/tests/baseline_images/test_mplot3d/bar3d_shaded.png
diff --git a/lib/mpl_toolkits/tests/baseline_images/test_mplot3d/tricontour.png b/lib/mpl_toolkits/tests/baseline_images/test_mplot3d/tricontour.png
diff --git a/lib/mpl_toolkits/tests/test_mplot3d.py b/lib/mpl_toolkits/tests/test_mplot3d.py
@@ -62,7 +62,7 @@ def test_bar3d_shaded():
     x2d, y2d = x2d.ravel(), y2d.ravel()
     z = x2d + y2d + 1  # Avoid triggering bug with zero-depth boxes.
 
-    views = [(-60, 30, 0), (30, 30, 0), (30, -30, 0), (120, -30, 0)]
+    views = [(-60, 30, 0), (30, 30, 30), (30, -30, -90), (120, -30, 0)]
     fig = plt.figure(figsize=plt.figaspect(1 / len(views)))
     axs = fig.subplots(
         1, len(views),
@@ -414,7 +414,7 @@ def test_marker_draw_order_view_rotated(fig_test, fig_ref):
     ax = fig_ref.add_subplot(projection='3d')
     ax.set_axis_off()
     ax.scatter(x, y, z, s=3500, c=color[::-1])  # color reversed
-    ax.view_init(elev=0, azim=azim - 180, roll=0)  # view rotated by 180 degrees
+    ax.view_init(elev=0, azim=azim - 180, roll=0)  # view rotated by 180 deg
 
 
 @mpl3d_image_comparison(['plot_3d_from_2d.png'], tol=0.015)
@@ -860,7 +860,8 @@ def _test_proj_make_M():
     E = np.array([1000, -1000, 2000])
     R = np.array([100, 100, 100])
     V = np.array([0, 0, 1])
-    viewM = proj3d.view_transformation(E, R, V)
+    roll = 0
+    viewM = proj3d.view_transformation(E, R, V, roll)
     perspM = proj3d.persp_transformation(100, -100)
     M = np.dot(perspM, viewM)
     return M
@@ -925,7 +926,8 @@ def test_proj_axes_cube_ortho():
     E = np.array([200, 100, 100])
     R = np.array([0, 0, 0])
     V = np.array([0, 0, 1])
-    viewM = proj3d.view_transformation(E, R, V)
+    roll = 0
+    viewM = proj3d.view_transformation(E, R, V, roll)
     orthoM = proj3d.ortho_transformation(-1, 1)
     M = np.dot(orthoM, viewM)
 
