Backport PR #15453: Improve example for tick locators

jklymak · MeeseeksDev[bot] · commit 2b5e044127d9 · 2019-10-20T22:51:34.000Z
diff --git a/examples/ticks_and_spines/tick-locators.py b/examples/ticks_and_spines/tick-locators.py
@@ -3,99 +3,76 @@
 Tick locators
 =============
 
-Show the different tick locators.
+Tick locators define the position of the ticks.
+
+This example illustrates the usage and effect of the most common locators.
 """
 
 import numpy as np
 import matplotlib.pyplot as plt
 import matplotlib.ticker as ticker
 
 
-# Setup a plot such that only the bottom spine is shown
-def setup(ax):
+def setup(ax, title):
+    """Set up common parameters for the Axes in the example."""
+    # only show the bottom spine
+    ax.yaxis.set_major_locator(ticker.NullLocator())
     ax.spines['right'].set_color('none')
     ax.spines['left'].set_color('none')
-    ax.yaxis.set_major_locator(ticker.NullLocator())
     ax.spines['top'].set_color('none')
+
     ax.xaxis.set_ticks_position('bottom')
-    ax.tick_params(which='major', width=1.00)
-    ax.tick_params(which='major', length=5)
-    ax.tick_params(which='minor', width=0.75)
-    ax.tick_params(which='minor', length=2.5)
+    ax.tick_params(which='major', width=1.00, length=5)
+    ax.tick_params(which='major', )
+    ax.tick_params(which='minor', width=0.75, length=2.5)
     ax.set_xlim(0, 5)
     ax.set_ylim(0, 1)
-    ax.patch.set_alpha(0.0)
+    ax.text(0.0, 0.2, title, transform=ax.transAxes,
+            fontsize=14, fontname='Monospace', color='tab:blue')
 
 
-plt.figure(figsize=(8, 6))
-n = 8
+fig, axs = plt.subplots(8, 1, figsize=(8, 6))
 
 # Null Locator
-ax = plt.subplot(n, 1, 1)
-setup(ax)
-ax.xaxis.set_major_locator(ticker.NullLocator())
-ax.xaxis.set_minor_locator(ticker.NullLocator())
-ax.text(0.0, 0.1, "NullLocator()", fontsize=14, transform=ax.transAxes)
+setup(axs[0], title="NullLocator()")
+axs[0].xaxis.set_major_locator(ticker.NullLocator())
+axs[0].xaxis.set_minor_locator(ticker.NullLocator())
 
 # Multiple Locator
-ax = plt.subplot(n, 1, 2)
-setup(ax)
-ax.xaxis.set_major_locator(ticker.MultipleLocator(0.5))
-ax.xaxis.set_minor_locator(ticker.MultipleLocator(0.1))
-ax.text(0.0, 0.1, "MultipleLocator(0.5)", fontsize=14,
-        transform=ax.transAxes)
+setup(axs[1], title="MultipleLocator(0.5)")
+axs[1].xaxis.set_major_locator(ticker.MultipleLocator(0.5))
+axs[1].xaxis.set_minor_locator(ticker.MultipleLocator(0.1))
 
 # Fixed Locator
-ax = plt.subplot(n, 1, 3)
-setup(ax)
-majors = [0, 1, 5]
-ax.xaxis.set_major_locator(ticker.FixedLocator(majors))
-minors = np.linspace(0, 1, 11)[1:-1]
-ax.xaxis.set_minor_locator(ticker.FixedLocator(minors))
-ax.text(0.0, 0.1, "FixedLocator([0, 1, 5])", fontsize=14,
-        transform=ax.transAxes)
+setup(axs[2], title="FixedLocator([0, 1, 5])")
+axs[2].xaxis.set_major_locator(ticker.FixedLocator([0, 1, 5]))
+axs[2].xaxis.set_minor_locator(ticker.FixedLocator(np.linspace(0.2, 0.8, 4)))
 
 # Linear Locator
-ax = plt.subplot(n, 1, 4)
-setup(ax)
-ax.xaxis.set_major_locator(ticker.LinearLocator(3))
-ax.xaxis.set_minor_locator(ticker.LinearLocator(31))
-ax.text(0.0, 0.1, "LinearLocator(numticks=3)",
-        fontsize=14, transform=ax.transAxes)
+setup(axs[3], title="LinearLocator(numticks=3)")
+axs[3].xaxis.set_major_locator(ticker.LinearLocator(3))
+axs[3].xaxis.set_minor_locator(ticker.LinearLocator(31))
 
 # Index Locator
-ax = plt.subplot(n, 1, 5)
-setup(ax)
-ax.plot(range(0, 5), [0]*5, color='white')
-ax.xaxis.set_major_locator(ticker.IndexLocator(base=.5, offset=.25))
-ax.text(0.0, 0.1, "IndexLocator(base=0.5, offset=0.25)",
-        fontsize=14, transform=ax.transAxes)
+setup(axs[4], title="IndexLocator(base=0.5, offset=0.25)")
+axs[4].plot(range(0, 5), [0]*5, color='white')
+axs[4].xaxis.set_major_locator(ticker.IndexLocator(base=0.5, offset=0.25))
 
 # Auto Locator
-ax = plt.subplot(n, 1, 6)
-setup(ax)
-ax.xaxis.set_major_locator(ticker.AutoLocator())
-ax.xaxis.set_minor_locator(ticker.AutoMinorLocator())
-ax.text(0.0, 0.1, "AutoLocator()", fontsize=14, transform=ax.transAxes)
+setup(axs[5], title="AutoLocator()")
+axs[5].xaxis.set_major_locator(ticker.AutoLocator())
+axs[5].xaxis.set_minor_locator(ticker.AutoMinorLocator())
 
 # MaxN Locator
-ax = plt.subplot(n, 1, 7)
-setup(ax)
-ax.xaxis.set_major_locator(ticker.MaxNLocator(4))
-ax.xaxis.set_minor_locator(ticker.MaxNLocator(40))
-ax.text(0.0, 0.1, "MaxNLocator(n=4)", fontsize=14, transform=ax.transAxes)
+setup(axs[6], title="MaxNLocator(n=4)")
+axs[6].xaxis.set_major_locator(ticker.MaxNLocator(4))
+axs[6].xaxis.set_minor_locator(ticker.MaxNLocator(40))
 
 # Log Locator
-ax = plt.subplot(n, 1, 8)
-setup(ax)
-ax.set_xlim(10**3, 10**10)
-ax.set_xscale('log')
-ax.xaxis.set_major_locator(ticker.LogLocator(base=10.0, numticks=15))
-ax.text(0.0, 0.1, "LogLocator(base=10, numticks=15)",
-        fontsize=15, transform=ax.transAxes)
-
-# Push the top of the top axes outside the figure because we only show the
-# bottom spine.
-plt.subplots_adjust(left=0.05, right=0.95, bottom=0.05, top=1.05)
+setup(axs[7], title="LogLocator(base=10, numticks=15)")
+axs[7].set_xlim(10**3, 10**10)
+axs[7].set_xscale('log')
+axs[7].xaxis.set_major_locator(ticker.LogLocator(base=10, numticks=15))
 
+plt.tight_layout()
 plt.show()
