TST/DOC: align collection relim tests and autolim semantics

tinezivic · tinezivic · commit bfdb6c958064 · 2026-04-21T00:14:58.000+02:00
diff --git a/lib/matplotlib/artist.py b/lib/matplotlib/artist.py
@@ -240,9 +240,6 @@ def remove(self):
         with `.FigureCanvasBase.draw_idle`.  Call `~.axes.Axes.relim` to
         update the Axes limits if desired.
 
-        Note: `~.axes.Axes.relim` will not see collections even if the
-        collection was added to the Axes with *autolim* = True.
-
         Note: there is no support for removing the artist's legend entry.
         """
 
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -2384,7 +2384,10 @@ def add_collection(self, collection, autolim=True):
         collection : `.Collection`
             The collection to add.
         autolim : bool
-            Whether to update data and view limits.
+            Whether to update data limits and request autoscaling.
+
+            If *False*, the collection is explicitly excluded from
+            `~.Axes.relim`.
 
             .. versionchanged:: 3.11
 
@@ -2406,17 +2409,17 @@ def add_collection(self, collection, autolim=True):
         if collection.get_clip_path() is None:
             collection.set_clip_path(self.patch)
 
+        # Keep relim() participation aligned with the autolim argument.
+        # autolim can also be the internal sentinel "_datalim_only".
+        collection._set_in_autoscale(bool(autolim))
+
         if autolim:
             # Make sure viewLim is not stale (mostly to match
             # pre-lazy-autoscale behavior, which is not really better).
             self._unstale_viewLim()
             self._update_collection_limits(collection)
             if autolim != "_datalim_only":
                 self._request_autoscale_view()
-            # Mark collection as participating in relim() only when autolim
-            # is enabled.  If autolim=False the caller explicitly opted out,
-            # so relim() must not pick this collection up later.
-            collection._set_in_autoscale(True)
 
         self.stale = True
         return collection
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -6515,65 +6515,56 @@ def test_relim_collection():
     fig, ax = plt.subplots()
     sc = ax.scatter([1, 2, 3], [4, 5, 6])
     ax.relim()
-    ax.autoscale_view()
-    xlim = ax.get_xlim()
-    ylim = ax.get_ylim()
-    assert xlim[0] <= 1 and xlim[1] >= 3
-    assert ylim[0] <= 4 and ylim[1] >= 6
+    expected = sc.get_datalim(ax.transData)
+    assert_allclose(ax.dataLim.get_points(), expected.get_points())
+    assert_allclose(ax.dataLim.minpos, expected.minpos)
 
     # After updating offsets, relim should track the new data.
     sc.set_offsets([[10, 20], [30, 40]])
     ax.relim()
-    ax.autoscale_view()
-    xlim = ax.get_xlim()
-    ylim = ax.get_ylim()
-    assert xlim[0] <= 10 and xlim[1] >= 30
-    assert ylim[0] <= 20 and ylim[1] >= 40
+    expected = sc.get_datalim(ax.transData)
+    assert_allclose(ax.dataLim.get_points(), expected.get_points())
+    assert_allclose(ax.dataLim.minpos, expected.minpos)
 
     # visible_only=True should ignore hidden collections.
     line, = ax.plot([0, 1], [0, 1])
     sc.set_visible(False)
     ax.relim(visible_only=True)
-    ax.autoscale_view()
-    xlim = ax.get_xlim()
-    ylim = ax.get_ylim()
     # With scatter hidden, limits should be driven by the line only.
-    assert xlim[1] < 10
-    assert ylim[1] < 10
+    assert_allclose(ax.dataLim.get_points(), [[0, 0], [1, 1]])
+    assert_array_equal(ax.dataLim.minpos, [np.inf, np.inf])
 
 
 def test_relim_collection_autolim_false():
     # GH#30859 - Collection added with autolim=False must not participate
     # in relim() later.
     import matplotlib.collections as mcollections
     fig, ax = plt.subplots()
-    ax.set_xlim(0, 1)
-    ax.set_ylim(0, 1)
+    ax.plot([0, 1], [0, 1])
+    ax.relim()
+    expected = ax.dataLim.frozen()
     # Build a collection far outside current limits and add it with autolim=False.
     sc = mcollections.PathCollection([])
     sc.set_offsets([[100, 200], [300, 400]])
     ax.add_collection(sc, autolim=False)
     ax.relim()
-    ax.autoscale_view()
-    # Limits must remain unchanged because autolim=False was requested.
-    assert ax.get_xlim() == (0, 1)
-    assert ax.get_ylim() == (0, 1)
+    # dataLim must remain unchanged because autolim=False was requested.
+    assert_allclose(ax.dataLim.get_points(), expected.get_points())
+    assert_allclose(ax.dataLim.minpos, expected.minpos)
 
 
 def test_relim_collection_log_scale():
     # GH#30859 - relim() for Collection on a log-scaled axis should
-    # correctly pick up minpos so that log scaling works properly.
+    # correctly propagate minpos into dataLim.
     fig, ax = plt.subplots()
     ax.set_xscale('log')
     ax.set_yscale('log')
     sc = ax.scatter([1e-3, 1e-2, 1e-1], [1e1, 1e2, 1e3])
     sc.set_offsets([[1e1, 1e4], [1e2, 1e5]])
     ax.relim()
-    ax.autoscale_view()
-    xlim = ax.get_xlim()
-    ylim = ax.get_ylim()
-    assert xlim[0] <= 1e1 and xlim[1] >= 1e2
-    assert ylim[0] <= 1e4 and ylim[1] >= 1e5
+    expected = sc.get_datalim(ax.transData)
+    assert_allclose(ax.dataLim.get_points(), expected.get_points())
+    assert_allclose(ax.dataLim.minpos, expected.minpos)
 
 
 def test_text_labelsize():
