From c3b82f77a3884e4e3cbcb42ac84f769f7e9a088e Mon Sep 17 00:00:00 2001
From: Ruth Comer <10599679+rcomer@users.noreply.github.com>
Date: Fri, 13 Dec 2024 15:00:01 +0000
Subject: [PATCH] FIX: zero width lines need no pattern

---
 lib/matplotlib/lines.py                  |  2 +-
 lib/matplotlib/tests/test_collections.py | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/matplotlib/lines.py b/lib/matplotlib/lines.py
index 65a4ccb6d950..a26ac72e2c1a 100644
--- a/lib/matplotlib/lines.py
+++ b/lib/matplotlib/lines.py
@@ -77,7 +77,7 @@ def _scale_dashes(offset, dashes, lw):
         return offset, dashes
     scaled_offset = offset * lw
     scaled_dashes = ([x * lw if x is not None else None for x in dashes]
-                     if dashes is not None else None)
+                     if dashes is not None and lw > 0 else None)
     return scaled_offset, scaled_dashes
 
 
diff --git a/lib/matplotlib/tests/test_collections.py b/lib/matplotlib/tests/test_collections.py
index 11934cfca2c3..10631120c54b 100644
--- a/lib/matplotlib/tests/test_collections.py
+++ b/lib/matplotlib/tests/test_collections.py
@@ -680,6 +680,16 @@ def test_set_wrong_linestyle():
         c.set_linestyle('fuzzy')
 
 
+@mpl.style.context('default')
+def test_zero_linewidth_scaling():
+    c = Collection()
+    c.set_linestyle('dashed')
+    c.set_linewidth(0)
+
+    # With a zero linewidth, there can be no pattern
+    assert c.get_linestyle() == [(0, None)]
+
+
 @mpl.style.context('default')
 def test_capstyle():
     col = mcollections.PathCollection([])