Avoid using gca() in examples.

... in favor of more idiomatic approaches.  (Except for examples
specifically about the stateful API.)

Author: anntzer

examples/axes_grid1/simple_anchored_artists.py

@@ -73,7 +73,7 @@ def draw_sizebar(ax):
     ax.add_artist(asb)
 
 
-ax = plt.gca()
+fig, ax = plt.subplots()
 ax.set_aspect(1.)
 
 draw_text(ax)

examples/scales/custom_scale.py

@@ -38,8 +38,8 @@ class MercatorLatitudeScale(mscale.ScaleBase):
     """
 
     # The scale class must have a member ``name`` that defines the string used
-    # to select the scale.  For example, ``gca().set_yscale("mercator")`` would
-    # be used to select this scale.
+    # to select the scale.  For example, ``ax.set_yscale("mercator")`` would be
+    # used to select this scale.
     name = 'mercator'
 
     def __init__(self, axis, *, thresh=np.deg2rad(85), **kwargs):
@@ -159,7 +159,7 @@ def inverted(self):
     s = np.radians(t)/2.
 
     plt.plot(t, s, '-', lw=2)
-    plt.gca().set_yscale('mercator')
+    plt.yscale('mercator')
 
     plt.xlabel('Longitude')
     plt.ylabel('Latitude')

examples/text_labels_and_annotations/text_alignment.py

@@ -9,18 +9,18 @@
 
 import matplotlib.pyplot as plt
 
+fig, ax = plt.subplots()
+
 # Build a rectangle in axes coords
 left, width = .25, .5
 bottom, height = .25, .5
 right = left + width
 top = bottom + height
-ax = plt.gca()
 p = plt.Rectangle((left, bottom), width, height, fill=False)
 p.set_transform(ax.transAxes)
 p.set_clip_on(False)
 ax.add_patch(p)
 
-
 ax.text(left, bottom, 'left top',
         horizontalalignment='left',
         verticalalignment='top',
@@ -75,6 +75,6 @@
         rotation=45,
         transform=ax.transAxes)
 
-plt.axis('off')
+ax.set_axis_off()
 
 plt.show()

examples/user_interfaces/embedding_in_wx5_sgskip.py

@@ -51,9 +51,9 @@ def demo():
     app = wit.InspectableApp()
     frame = wx.Frame(None, -1, 'Plotter')
     plotter = PlotNotebook(frame)
-    axes1 = plotter.add('figure 1').gca()
+    axes1 = plotter.add('figure 1').add_subplot()
     axes1.plot([1, 2, 3], [2, 1, 4])
-    axes2 = plotter.add('figure 2').gca()
+    axes2 = plotter.add('figure 2').add_subplot()
     axes2.plot([1, 2, 3, 4, 5], [2, 1, 4, 2, 3])
     frame.Show()
     app.MainLoop()