From 76a405c9dcd337c0e1b7168d6ea2ce425f0ae784 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Fri, 17 Apr 2020 16:23:03 +0200
Subject: [PATCH] Convert SubplotZero example into centered-spines-with-arrows
 recipe.

---
 examples/axisartist/demo_axisline_style.py    | 32 ----------
 .../recipes/centered_spines_with_arrows.py    | 58 +++++++++++++++++++
 2 files changed, 58 insertions(+), 32 deletions(-)
 delete mode 100644 examples/axisartist/demo_axisline_style.py
 create mode 100644 examples/recipes/centered_spines_with_arrows.py

diff --git a/examples/axisartist/demo_axisline_style.py b/examples/axisartist/demo_axisline_style.py
deleted file mode 100644
index fc61375147e4..000000000000
--- a/examples/axisartist/demo_axisline_style.py
+++ /dev/null
@@ -1,32 +0,0 @@
-"""
-================
-Axis line styles
-================
-
-This example shows some configurations for axis style.
-"""
-
-from mpl_toolkits.axisartist.axislines import SubplotZero
-import matplotlib.pyplot as plt
-import numpy as np
-
-
-fig = plt.figure()
-ax = SubplotZero(fig, 111)
-fig.add_subplot(ax)
-
-for direction in ["xzero", "yzero"]:
-    # adds arrows at the ends of each axis
-    ax.axis[direction].set_axisline_style("-|>")
-
-    # adds X and Y-axis from the origin
-    ax.axis[direction].set_visible(True)
-
-for direction in ["left", "right", "bottom", "top"]:
-    # hides borders
-    ax.axis[direction].set_visible(False)
-
-x = np.linspace(-0.5, 1., 100)
-ax.plot(x, np.sin(x*np.pi))
-
-plt.show()
diff --git a/examples/recipes/centered_spines_with_arrows.py b/examples/recipes/centered_spines_with_arrows.py
new file mode 100644
index 000000000000..c1ab69842e55
--- /dev/null
+++ b/examples/recipes/centered_spines_with_arrows.py
@@ -0,0 +1,58 @@
+"""
+===========================
+Centered spines with arrows
+===========================
+
+This examples shows two ways to draw a "math textbook" style plot, where the
+spines ("axes lines") are drawn at ``x = 0`` and ``y = 0``, and have arrows at
+their ends.
+"""
+
+import matplotlib.pyplot as plt
+from mpl_toolkits.axisartist.axislines import SubplotZero
+import numpy as np
+
+
+fig, ax = plt.subplots()
+# Move the left and bottom spines to x = 0 and y = 0, respectively.
+ax.spines["left"].set_position(("data", 0))
+ax.spines["bottom"].set_position(("data", 0))
+# Hide the top and right spines.
+ax.spines["top"].set_visible(False)
+ax.spines["right"].set_visible(False)
+
+# Draw arrows (as black triangles: ">k"/"^k") at the end of the axes.  In each
+# case, one of the coordinates (0) is a data coordinate (i.e., y = 0 or x = 0,
+# respectively) and the other one (1) is an axes coordinate (i.e., at the very
+# right/top of the axes).  Also, disable clipping (clip_on=False) as the marker
+# actually spills out of the axes.
+ax.plot(1, 0, ">k", transform=ax.get_yaxis_transform(), clip_on=False)
+ax.plot(0, 1, "^k", transform=ax.get_xaxis_transform(), clip_on=False)
+
+# Some sample data.
+x = np.linspace(-0.5, 1., 100)
+ax.plot(x, np.sin(x*np.pi))
+
+###############################################################################
+# Alternatively, one can use mpl_toolkit's SubplotZero, but note that many
+# standard Matplotlib options (e.g. rcParams) have no effect.
+
+fig = plt.figure()
+ax = SubplotZero(fig, 111)
+fig.add_subplot(ax)
+
+for direction in ["xzero", "yzero"]:
+    # adds arrows at the ends of each axis
+    ax.axis[direction].set_axisline_style("-|>")
+    # adds X and Y-axis from the origin
+    ax.axis[direction].set_visible(True)
+
+for direction in ["left", "right", "bottom", "top"]:
+    # hides borders
+    ax.axis[direction].set_visible(False)
+
+x = np.linspace(-0.5, 1., 100)
+ax.plot(x, np.sin(x*np.pi))
+
+
+plt.show()