matplotlib · ksunden · Oct 17, 2023 · Sep 26, 2023 · Sep 26, 2023 · Sep 28, 2023
diff --git a/lib/matplotlib/mpl-data/matplotlibrc b/lib/matplotlib/mpl-data/matplotlibrc
@@ -669,14 +669,14 @@
 #path.snap: True  # When True, rectilinear axis-aligned paths will be snapped
                   # to the nearest pixel when certain criteria are met.
                   # When False, paths will never be snapped.
-#path.sketch: None  # May be None, or a 3-tuple of the form:
-                    # (scale, length, randomness).
-                    #     - *scale* is the amplitude of the wiggle
-                    #         perpendicular to the line (in pixels).
-                    #     - *length* is the length of the wiggle along the
-                    #         line (in pixels).
-                    #     - *randomness* is the factor by which the length is
-                    #         randomly scaled.
+#path.sketch: None  # May be None, or a tuple of the form:
+                    #  path.sketch: (scale, length, randomness) 
+                    # - *scale* is the amplitude of the wiggle
+                    #    perpendicular to the line (in pixels).
+                    # - *length* is the length of the wiggle along the
+                    #    line (in pixels).
+                    # - *randomness* is the factor by which the length is
+                    #    randomly scaled.
 #path.effects:
 
 

diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -555,14 +555,17 @@ def validate_bbox(s):
 
 
 def validate_sketch(s):
+
     if isinstance(s, str):
-        s = s.lower()
+        s = s.lower().strip()
+        if s.startswith("(") and s.endswith(")"):
+            s = s[1:-1]
     if s == 'none' or s is None:
         return None
     try:
         return tuple(_listify_validator(validate_float, n=3)(s))
-    except ValueError:
-        raise ValueError("Expected a (scale, length, randomness) triplet")
+    except ValueError as exc:
+        raise ValueError("Expected a (scale, length, randomness) tuple") from exc
 
 
 def _validate_greaterthan_minushalf(s):

diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
@@ -27,6 +27,7 @@
     validate_int,
     validate_markevery,
     validate_stringlist,
+    validate_sketch,
     _validate_linestyle,
     _listify_validator)
 
@@ -628,3 +629,26 @@ def test_rcparams_legend_loc_from_file(tmpdir, value):
 
     with mpl.rc_context(fname=rc_path):
         assert mpl.rcParams["legend.loc"] == value
+
+
+@pytest.mark.parametrize("value", [(1, 2, 3), '1, 2, 3', '(1, 2, 3)'])
+def test_validate_sketch(value):
+    mpl.rcParams["path.sketch"] = value
+    assert mpl.rcParams["path.sketch"] == (1, 2, 3)
+    assert validate_sketch(value) == (1, 2, 3)
+
+
+@pytest.mark.parametrize("value", [1, '1', '1 2 3'])
+def test_validate_sketch_error(value):
+    with pytest.raises(ValueError, match="scale, length, randomness"):
+        validate_sketch(value)
+    with pytest.raises(ValueError, match="scale, length, randomness"):
+        mpl.rcParams["path.sketch"] = value
+
+
+@pytest.mark.parametrize("value", ['1, 2, 3', '(1,2,3)'])
+def test_rcparams_path_sketch_from_file(tmpdir, value):
+    rc_path = tmpdir.join("matplotlibrc")
+    rc_path.write(f"path.sketch: {value}")
+    with mpl.rc_context(fname=rc_path):
+        assert mpl.rcParams["path.sketch"] == (1, 2, 3)