From 0eed653805124aff8270683a024b6b3dca52c713 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Wed, 10 Apr 2019 06:45:11 +0200
Subject: [PATCH] Backport PR #13835: Improve Conectionstyle Demo

---
 .flake8                                   |  1 +
 examples/userdemo/connectionstyle_demo.py | 33 +++++++++++++++--------
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/.flake8 b/.flake8
index 546c5f39d628..aa7c8e5dd2ed 100644
--- a/.flake8
+++ b/.flake8
@@ -257,6 +257,7 @@ per-file-ignores =
     examples/user_interfaces/mpl_with_glade3_sgskip.py: E402
     examples/user_interfaces/pylab_with_gtk_sgskip.py: E302, E402
     examples/user_interfaces/toolmanager_sgskip.py: E402
+    examples/userdemo/connectionstyle_demo.py: E402
     examples/userdemo/custom_boxstyle01.py: E402
     examples/userdemo/pgf_preamble_sgskip.py: E402
     examples/userdemo/simple_annotate01.py: E501
diff --git a/examples/userdemo/connectionstyle_demo.py b/examples/userdemo/connectionstyle_demo.py
index 1ea2bf5fe8fd..d429822b6965 100644
--- a/examples/userdemo/connectionstyle_demo.py
+++ b/examples/userdemo/connectionstyle_demo.py
@@ -3,17 +3,15 @@
 Connectionstyle Demo
 ====================
 
+When creating an annotation using `~.Axes.annotate`, the arrow shape can be
+controlled via the *connectionstyle* parameter of *arrowprops*. For further
+details see the description of `.FancyArrowPatch`.
 """
 
 import matplotlib.pyplot as plt
 
 
-fig, axs = plt.subplots(3, 5, figsize=(8, 4.8))
-x1, y1 = 0.3, 0.3
-x2, y2 = 0.7, 0.7
-
-
-def demo_con_style(ax, connectionstyle, label=None):
+def demo_con_style(ax, connectionstyle):
     x1, y1 = 0.3, 0.2
     x2, y2 = 0.8, 0.6
 
@@ -21,11 +19,9 @@ def demo_con_style(ax, connectionstyle, label=None):
     ax.annotate("",
                 xy=(x1, y1), xycoords='data',
                 xytext=(x2, y2), textcoords='data',
-                arrowprops=dict(arrowstyle="->",
-                                color="0.5",
+                arrowprops=dict(arrowstyle="->", color="0.5",
                                 shrinkA=5, shrinkB=5,
-                                patchA=None,
-                                patchB=None,
+                                patchA=None, patchB=None,
                                 connectionstyle=connectionstyle,
                                 ),
                 )
@@ -34,6 +30,7 @@ def demo_con_style(ax, connectionstyle, label=None):
             transform=ax.transAxes, ha="left", va="top")
 
 
+fig, axs = plt.subplots(3, 5, figsize=(8, 4.8))
 demo_con_style(axs[0, 0], "angle3,angleA=90,angleB=0")
 demo_con_style(axs[1, 0], "angle3,angleA=0,angleB=90")
 demo_con_style(axs[0, 1], "arc3,rad=0.")
@@ -51,6 +48,20 @@ def demo_con_style(ax, connectionstyle, label=None):
 
 for ax in axs.flat:
     ax.set(xlim=(0, 1), ylim=(0, 1), xticks=[], yticks=[], aspect=1)
-fig.tight_layout(pad=0)
+fig.tight_layout(pad=0.2)
 
 plt.show()
+
+#############################################################################
+#
+# ------------
+#
+# References
+# """"""""""
+#
+# The use of the following functions, methods, classes and modules is shown
+# in this example:
+
+import matplotlib
+matplotlib.axes.Axes.annotate
+matplotlib.patches.FancyArrowPatch