From 8e681524a0857db45c9b4c10827a0dbd2c8c376f Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Tue, 13 Feb 2018 17:10:33 +0100
Subject: [PATCH] Make the filternorm prop of Images a boolean rather than a
 {0,1} scalar.

This seems a bit more pythonic and the C-API handles bools just as well.
Also filternorm and filterrad are always defined (as bool and float,
respectively, so no need to add `... or 0.0` when passing them to the
C-API.
---
 lib/matplotlib/axes/_axes.py |  6 +++---
 lib/matplotlib/image.py      | 23 ++++++++++-------------
 2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
index 0292ccb64218..65f66e35c90e 100644
--- a/lib/matplotlib/axes/_axes.py
+++ b/lib/matplotlib/axes/_axes.py
@@ -5170,9 +5170,9 @@ def imshow(self, X, cmap=None, norm=None, aspect=None,
         shape : scalars (columns, rows), optional, default: None
             For raw buffer images
 
-        filternorm : scalar, optional, default: 1
-            A parameter for the antigrain image resize filter.  From the
-            antigrain documentation, if `filternorm` = 1, the filter
+        filternorm : bool, optional, default: True
+            A parameter for the antigrain image resize filter (see the
+            antigrain documentation).  If *filternorm* is set, the filter
             normalizes integer values and corrects the rounding errors. It
             doesn't do anything with the source floating point values, it
             corrects only integers according to the rule of 1.0 which means
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
index bb47d804699f..81357ecb2cc4 100644
--- a/lib/matplotlib/image.py
+++ b/lib/matplotlib/image.py
@@ -188,7 +188,7 @@ def __init__(self, ax,
                  norm=None,
                  interpolation=None,
                  origin=None,
-                 filternorm=1,
+                 filternorm=True,
                  filterrad=4.0,
                  resample=False,
                  **kwargs
@@ -424,7 +424,7 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                                 _interpd_[self.get_interpolation()],
                                 self.get_resample(), 1.0,
                                 self.get_filternorm(),
-                                self.get_filterrad() or 0.0)
+                                self.get_filterrad())
 
                 # we are done with A_scaled now, remove from namespace
                 # to be sure!
@@ -459,7 +459,7 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                                 _interpd_[self.get_interpolation()],
                                 True, 1,
                                 self.get_filternorm(),
-                                self.get_filterrad() or 0.0)
+                                self.get_filterrad())
                 # we are done with the mask, delete from namespace to be sure!
                 del mask
                 # Agg updates the out_mask in place.  If the pixel has
@@ -492,7 +492,7 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                 _image.resample(
                     A, output, t, _interpd_[self.get_interpolation()],
                     self.get_resample(), alpha,
-                    self.get_filternorm(), self.get_filterrad() or 0.0)
+                    self.get_filternorm(), self.get_filterrad())
 
             # at this point output is either a 2D array of normed data
             # (of int or float)
@@ -735,20 +735,17 @@ def get_resample(self):
 
     def set_filternorm(self, filternorm):
         """
-        Set whether the resize filter norms the weights -- see
-        help for imshow
+        Set whether the resize filter normalizes the weights.
 
-        ACCEPTS: 0 or 1
-        """
-        if filternorm:
-            self._filternorm = 1
-        else:
-            self._filternorm = 0
+        See help for `~.Axes.imshow`.
 
+        .. ACCEPTS: bool
+        """
+        self._filternorm = bool(filternorm)
         self.stale = True
 
     def get_filternorm(self):
-        """Return the filternorm setting."""
+        """Return whether the resize filter normalizes the weights."""
         return self._filternorm
 
     def set_filterrad(self, filterrad):