Move Axes.images into hidden children attribute.

The images can still be accessed via a read-only property, but now are
combined with lines, patches, tables and texts for sorting and drawing
purposes.

Author: QuLogic

lib/matplotlib/axes/_base.py

@@ -1233,7 +1233,6 @@ def cla(self):
         self._gridOn = mpl.rcParams['axes.grid']
         self._children = []
         self.artists = []
-        self.images = []
         self._mouseover_set = _OrderedSet()
         self.child_axes = []
         self._current_image = None  # strictly for pyplot via _sci, _gci
@@ -1307,6 +1306,11 @@ def cla(self):
 
         self.stale = True
 
+    @property
+    def images(self):
+        return tuple(a for a in self._children
+                     if isinstance(a, mimage.AxesImage))
+
     @property
     def lines(self):
         return tuple(a for a in self._children if isinstance(a, mlines.Line2D))
@@ -2097,13 +2101,13 @@ def add_collection(self, collection, autolim=True):
 
     def add_image(self, image):
         """
-        Add an `~.AxesImage` to the axes' images; return the image.
+        Add an `~.AxesImage` to the Axes; return the image.
         """
         self._set_artist_props(image)
         if not image.get_label():
-            image.set_label('_image%d' % len(self.images))
-        self.images.append(image)
-        image._remove_method = self.images.remove
+            image.set_label(f'_child{len(self._children)}')
+        self._children.append(image)
+        image._remove_method = self._children.remove
         self.stale = True
         return image
 
@@ -2911,8 +2915,9 @@ def draw(self, renderer=None, inframe=False):
             artists.remove(self._right_title)
 
         if not self.figure.canvas.is_saving():
-            artists = [a for a in artists
-                       if not a.get_animated() or a in self.images]
+            artists = [
+                a for a in artists
+                if not a.get_animated() or isinstance(a, mimage.AxesImage)]
         artists = sorted(artists, key=attrgetter('zorder'))
 
         # rasterize artists with negative zorder
@@ -4347,7 +4352,6 @@ def get_children(self):
             *self.spines.values(),
             *self._get_axis_list(),
             self.title, self._left_title, self._right_title,
-            *self.images,
             *self.child_axes,
             *([self.legend_] if self.legend_ is not None else []),
             self.patch,

lib/mpl_toolkits/axes_grid1/parasite_axes.py

@@ -2,6 +2,7 @@
 
 from matplotlib import _api
 import matplotlib.artist as martist
+import matplotlib.image as mimage
 import matplotlib.transforms as mtransforms
 from matplotlib.axes import subplot_class_factory
 from matplotlib.transforms import Bbox
@@ -24,9 +25,18 @@ def cla(self):
         self._get_lines = self._parent_axes._get_lines
 
     def get_images_artists(self):
-        artists = {a for a in self.get_children() if a.get_visible()}
-        images = {a for a in self.images if a.get_visible()}
-        return list(images), list(artists - images)
+        artists = []
+        images = []
+
+        for a in self.get_children():
+            if not a.get_visible():
+                continue
+            if isinstance(a, mimage.AxesImage):
+                images.append(a)
+            else:
+                artists.append(a)
+
+        return images, artists
 
     def pick(self, mouseevent):
         # This most likely goes to Artist.pick (depending on axes_class given
@@ -204,7 +214,7 @@ def _get_legend_handles(self, legend_handler_map=None):
     def draw(self, renderer):
 
         orig_artists = list(self.artists)
-        orig_images = list(self.images)
+        orig_children_len = len(self._children)
 
         if hasattr(self, "get_axes_locator"):
             locator = self.get_axes_locator()
@@ -222,12 +232,12 @@ def draw(self, renderer):
         for ax in self.parasites:
             ax.apply_aspect(rect)
             images, artists = ax.get_images_artists()
-            self.images.extend(images)
+            self._children.extend(images)
             self.artists.extend(artists)
 
         super().draw(renderer)
         self.artists = orig_artists
-        self.images = orig_images
+        self._children = self._children[:orig_children_len]
 
     def cla(self):
         for ax in self.parasites: