Simplify PolarAxes.can_pan.

anntzer · anntzer · commit 38474719d52a · 2019-03-08T11:18:23.000+01:00
In the modified code, dt0 is always == -dt1 so they have the same
absolute value and the else clause is always triggered.

This is used in polar pan mode, which, when using the left mouse button,
allows one to move the radial tick labels around... (the right mouse
button allows zooming in and out (changing rmax, which seems less
obscure.)
diff --git a/lib/matplotlib/projections/polar.py b/lib/matplotlib/projections/polar.py
@@ -1398,13 +1398,7 @@ def drag_pan(self, button, key, x, y):
             t, r = p.trans_inverse.transform_point((x, y))
 
             # Deal with theta
-            dt0 = t - startt
-            dt1 = startt - t
-            if abs(dt1) < abs(dt0):
-                dt = abs(dt1) * np.sign(dt0) * -1.0
-            else:
-                dt = dt0 * -1.0
-            dt = (dt / np.pi) * 180.0
+            dt = np.rad2deg(startt - t)
             self.set_rlabel_position(p.r_label_angle - dt)
 
             trans, vert1, horiz1 = self.get_yaxis_text1_transform(0.0)
