FIX: savefig)...,transparent=True) now makes inset_axes transparent as well

sramesh750 · anntzer · commit cc70a86b02dc · 2022-04-17T00:26:56.000+02:00
FIX: Indented child axes to be inside previous loop to fix local variable error

Added test for setting transparent inset axes in savefig function, added code to savefig to ensure that subfigures also made transparent + corresponding test

Added baseline images corresponding to newly added tests for figure.py

Changed test_savefig_transparent_subfigure to add subplots to subfigures created so that baseline image is not completely blank

Combined test_savefig_transparent_inset_axes and test_savefig_transparent_subfigure into one test: test_savefig_transparent and added remove_text=True to image_comparison wrapper function

Removed older baseline images that we no longer need

Fixed flake8 issues with test_figure.py
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -3061,10 +3061,18 @@ def savefig(self, fname, *, transparent=None, **kwargs):
             if transparent:
                 kwargs.setdefault('facecolor', 'none')
                 kwargs.setdefault('edgecolor', 'none')
+                for subfig in self.subfigs:
+                    subfig.set_facecolor('none')
+                    subfig.set_edgecolor('none')
+                # set axes to be transparent
                 for ax in self.axes:
                     stack.enter_context(
                         ax.patch._cm_set(facecolor='none', edgecolor='none'))
-
+                    # set inset axes to be transparent as well
+                    for child_ax in ax.child_axes:
+                        stack.enter_context(
+                            child_ax.patch._cm_set(
+                                facecolor='none', edgecolor='none'))
             self.canvas.print_figure(fname, **kwargs)
 
     def ginput(self, n=1, timeout=30, show_clicks=True,
diff --git a/lib/matplotlib/tests/baseline_images/test_figure/transparent_background.png b/lib/matplotlib/tests/baseline_images/test_figure/transparent_background.png
diff --git a/lib/matplotlib/tests/test_figure.py b/lib/matplotlib/tests/test_figure.py
@@ -557,6 +557,24 @@ def test_savefig_pixel_ratio(backend):
     assert ratio1 == ratio2
 
 
+@image_comparison(['transparent_background'],
+                    extensions=['png'], savefig_kwarg={'transparent': True},
+                    remove_text=True)
+def test_savefig_transparent():
+    # create two transparent subfigures with corresponding transparent inset
+    # axes. the entire background of the image should be transparent.
+    fig = plt.gcf()
+    gs = fig.add_gridspec(3, 3)
+    fig.add_subfigure(gs[0, 0])
+    fig.add_subplot(gs[0, 0])
+    ax = plt.gca()
+    ax.inset_axes([.1, .2, .3, .4])
+    fig.add_subfigure(gs[0:2, 1])
+    fig.add_subplot(gs[0:2, 1])
+    ax2 = plt.gca()
+    ax2.inset_axes([.1, .2, .3, .4])
+
+
 def test_figure_repr():
     fig = plt.figure(figsize=(10, 20), dpi=10)
     assert repr(fig) == "<Figure size 100x200 with 0 Axes>"
