From 2d9fded786056fcb9bc6e50c727a74c7748a2397 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Wed, 11 Oct 2017 00:28:19 -0700
Subject: [PATCH 1/2] Minor cleanups to Axes._drag_pan.

---
 lib/matplotlib/axes/_base.py | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
index 00cc9ee7aa4a..c1d91781624c 100644
--- a/lib/matplotlib/axes/_base.py
+++ b/lib/matplotlib/axes/_base.py
@@ -3803,7 +3803,7 @@ def format_deltas(key, dx, dy):
                     dy = dy / abs(dy) * abs(dx)
                 else:
                     dx = dx / abs(dx) * abs(dy)
-            return (dx, dy)
+            return dx, dy
 
         p = self._pan_start
         dx = x - p.x
@@ -3812,23 +3812,20 @@ def format_deltas(key, dx, dy):
             return
         if button == 1:
             dx, dy = format_deltas(key, dx, dy)
-            result = p.bbox.translated(-dx, -dy) \
-                .transformed(p.trans_inverse)
+            result = p.bbox.translated(-dx, -dy).transformed(p.trans_inverse)
         elif button == 3:
             try:
-                dx = -dx / float(self.bbox.width)
-                dy = -dy / float(self.bbox.height)
+                dx = -dx / self.bbox.width
+                dy = -dy / self.bbox.height
                 dx, dy = format_deltas(key, dx, dy)
                 if self.get_aspect() != 'auto':
-                    dx = 0.5 * (dx + dy)
-                    dy = dx
-
+                    dx = dy = 0.5 * (dx + dy)
                 alpha = np.power(10.0, (dx, dy))
                 start = np.array([p.x, p.y])
                 oldpoints = p.lim.transformed(p.trans)
                 newpoints = start + alpha * (oldpoints - start)
-                result = mtransforms.Bbox(newpoints) \
-                    .transformed(p.trans_inverse)
+                result = (mtransforms.Bbox(newpoints)
+                          .transformed(p.trans_inverse))
             except OverflowError:
                 warnings.warn('Overflow while panning')
                 return

From b848e8a88b7bfcc354a18b9a01e92da2b80cc568 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Thu, 12 Oct 2017 16:32:15 -0700
Subject: [PATCH 2/2] Ignore invalid limits in pan.

---
 lib/matplotlib/axes/_base.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
index c1d91781624c..08dfb51b0705 100644
--- a/lib/matplotlib/axes/_base.py
+++ b/lib/matplotlib/axes/_base.py
@@ -3830,8 +3830,12 @@ def format_deltas(key, dx, dy):
                 warnings.warn('Overflow while panning')
                 return
 
-        self.set_xlim(*result.intervalx)
-        self.set_ylim(*result.intervaly)
+        valid = np.isfinite(result.transformed(p.trans))
+        points = result.get_points().astype(object)
+        # Just ignore invalid limits (typically, underflow in log-scale).
+        points[~valid] = None
+        self.set_xlim(points[:, 0])
+        self.set_ylim(points[:, 1])
 
     @cbook.deprecated("2.1")
     def get_cursor_props(self):