From e2679d7a15595e200ce948ef63cc943b58ab716e Mon Sep 17 00:00:00 2001
From: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
Date: Sat, 28 Mar 2026 03:14:52 +0100
Subject: [PATCH] MNT: Minor cleanup of label formatting in
 PathCollection.legend_elements

---
 lib/matplotlib/collections.py | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
index 27b3789a3105..b2f8255367e8 100644
--- a/lib/matplotlib/collections.py
+++ b/lib/matplotlib/collections.py
@@ -1271,7 +1271,15 @@ def legend_elements(self, prop="colors", num="auto",
               "alpha": self.get_alpha(),
               **kwargs}
 
-        for val, lab in zip(values, label_values):
+        # Pre-format all labels
+        # TODO: check whether we can switch to
+        #       formatted_labels = fmt.format_ticks(label_values)
+        #       There are subtle differences for some formatters as that passes the
+        #       indices to __call__ as well.
+        fmt.set_locs(label_values)
+        formatted_labels = [fmt(lab) for lab in label_values]
+
+        for val, formatted in zip(values, formatted_labels):
             if prop == "colors":
                 color = self.cmap(self.norm(val))
             elif prop == "sizes":
@@ -1281,10 +1289,7 @@ def legend_elements(self, prop="colors", num="auto",
             h = mlines.Line2D([0], [0], ls="", color=color, ms=size,
                               marker=self.get_paths()[0], **kw)
             handles.append(h)
-            if hasattr(fmt, "set_locs"):
-                fmt.set_locs(label_values)
-            l = fmt(lab)
-            labels.append(l)
+            labels.append(formatted)
 
         return handles, labels