Merge pull request matplotlib#18646 from anntzer/figure

Support activating figures with plt.figure(figure_instance).

Author: jklymak

lib/matplotlib/pyplot.py

@@ -657,7 +657,7 @@ def figure(num=None,  # autoincrement if None, else integer from 1-N
 
     Parameters
     ----------
-    num : int or str, optional
+    num : int or str or `.Figure`, optional
         A unique identifier for the figure.
 
         If a figure with that identifier already exists, this figure is made
@@ -728,6 +728,11 @@ def figure(num=None,  # autoincrement if None, else integer from 1-N
     `~matplotlib.rcParams` defines the default values, which can be modified
     in the matplotlibrc file.
     """
+    if isinstance(num, Figure):
+        if num.canvas.manager is None:
+            raise ValueError("The passed figure is not managed by pyplot")
+        _pylab_helpers.Gcf.set_active(num.canvas.manager)
+        return num
 
     allnums = get_fignums()
     next_num = max(allnums) + 1 if allnums else 1
@@ -1055,9 +1060,7 @@ def sca(ax):
     """
     Set the current Axes to *ax* and the current Figure to the parent of *ax*.
     """
-    if not hasattr(ax.figure.canvas, "manager"):
-        raise ValueError("Axes parent figure is not managed by pyplot")
-    _pylab_helpers.Gcf.set_active(ax.figure.canvas.manager)
+    figure(ax.figure)
     ax.figure.sca(ax)
 
 

lib/matplotlib/tests/test_figure.py

@@ -10,6 +10,7 @@
 from matplotlib import cbook, rcParams
 from matplotlib.testing.decorators import image_comparison, check_figures_equal
 from matplotlib.axes import Axes
+from matplotlib.figure import Figure
 from matplotlib.ticker import AutoMinorLocator, FixedFormatter, ScalarFormatter
 import matplotlib.pyplot as plt
 import matplotlib.dates as mdates
@@ -60,10 +61,9 @@ def test_align_labels():
 
 
 def test_figure_label():
-    # pyplot figure creation, selection and closing with figure label and
-    # number
+    # pyplot figure creation, selection, and closing with label/number/instance
     plt.close('all')
-    plt.figure('today')
+    fig_today = plt.figure('today')
     plt.figure(3)
     plt.figure('tomorrow')
     plt.figure()
@@ -78,6 +78,10 @@ def test_figure_label():
     plt.close('tomorrow')
     assert plt.get_fignums() == [0, 1]
     assert plt.get_figlabels() == ['', 'today']
+    plt.figure(fig_today)
+    assert plt.gcf() == fig_today
+    with pytest.raises(ValueError):
+        plt.figure(Figure())
 
 
 def test_fignum_exists():