From 6d4c69dfba182eb46b9361940108ad91dfb491ef Mon Sep 17 00:00:00 2001
From: Charlie Wang <charliewang@MacBook-Pro-3.local>
Date: Sun, 29 Jul 2018 17:41:00 -0700
Subject: [PATCH] Re-factor _parse_args for quiver/barb to handle the case when
 keyword arguements are used instead of positional arguements. If both are
 given at the same time, positional will be chosen by default.

---
 lib/matplotlib/quiver.py | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/matplotlib/quiver.py b/lib/matplotlib/quiver.py
index 9b63e7734198..89f0bc195b68 100644
--- a/lib/matplotlib/quiver.py
+++ b/lib/matplotlib/quiver.py
@@ -381,10 +381,17 @@ def contains(self, mouseevent):
 # This is a helper function that parses out the various combination of
 # arguments for doing colored vector plots.  Pulling it out here
 # allows both Quiver and Barbs to use it
-def _parse_args(*args):
+def _parse_args(*args, **kwargs):
     X, Y, U, V, C = [None] * 5
     args = list(args)
 
+    if len(args) == 0:
+        if kwargs.get("X") != None: args.append(kwargs.pop("X")) 
+        if kwargs.get("Y") != None: args.append(kwargs.pop("Y")) 
+        if kwargs.get("U") != None: args.append(kwargs.pop("U")) 
+        if kwargs.get("V") != None: args.append(kwargs.pop("V")) 
+        if kwargs.get("C") != None: args.append(kwargs.pop("C"))
+
     # The use of atleast_1d allows for handling scalar arguments while also
     # keeping masked arrays
     if len(args) == 3 or len(args) == 5:
@@ -402,7 +409,7 @@ def _parse_args(*args):
     else:
         indexgrid = np.meshgrid(np.arange(nc), np.arange(nr))
         X, Y = [np.ravel(a) for a in indexgrid]
-    return X, Y, U, V, C
+    return X, Y, U, V, C, args, kwargs
 
 
 def _check_consistent_shapes(*arrays):
@@ -443,7 +450,9 @@ def __init__(self, ax, *args,
         %s
         """
         self.ax = ax
-        X, Y, U, V, C = _parse_args(*args)
+        # If **kw is used for input then output a new set of *args, **kw
+        # once it has been parsed out. See _parse_args
+        X, Y, U, V, C, args, kw = _parse_args(*args, **kw)
         self.X = X
         self.Y = Y
         self.XY = np.column_stack((X, Y))
@@ -950,7 +959,9 @@ def __init__(self, ax, *args,
             kw['linewidth'] = 1
 
         # Parse out the data arrays from the various configurations supported
-        x, y, u, v, c = _parse_args(*args)
+        # If **kw is used for input then output a new set of *args, **kw
+        # once it has been parsed out. See _parse_args
+        x, y, u, v, c, args, kw = _parse_args(*args, **kw)
         self.x = x
         self.y = y
         xy = np.column_stack((x, y))