fix: consume Matplotlib format markers (#144)

* fix: consume Matplotlib format markers

* test: cover compact marker formats and invalid leftovers

Check marker formats, tuple input, option precedence and rejection of unmatched characters.

---------

Co-authored-by: Peter Corke <peter.i.corke@gmail.com>

Author: RoboX2020

src/machinevisiontoolbox/base/graphics.py

@@ -1014,6 +1014,7 @@ def parse_matplotlib_fmt(fmt: str):
         marker_match = re.search(marker_pattern, working_fmt)
         if marker_match:
             res["marker"] = marker_match.group(0)
+            working_fmt = working_fmt.replace(res["marker"], "", 1)
 
         if len(working_fmt.strip()) > 0:
             raise ValueError(

tests/base/test_mpl_styling.py

@@ -0,0 +1,42 @@
+"""Compact Matplotlib markers must be consumed before checking leftovers."""
+
+import matplotlib.pyplot as plt
+import pytest
+
+from machinevisiontoolbox.base import mpl_styling
+
+
+@pytest.mark.parametrize(
+    "fmt, expected",
+    [
+        ("o", {"marker": "o"}),
+        ("ro--", {"color": "r", "marker": "o", "linestyle": "--"}),
+        ("g^:", {"color": "g", "marker": "^", "linestyle": ":"}),
+        ("-.b*", {"color": "b", "marker": "*", "linestyle": "-."}),
+        (("ro--",), {"color": "r", "marker": "o", "linestyle": "--"}),
+    ],
+)
+def test_marker_formats(fmt, expected):
+    options = mpl_styling(fmt, {}, {})
+    assert options == expected
+    fig, ax = plt.subplots()
+    try:
+        (line,) = ax.plot([0, 1], [0, 1], **options)
+        assert line.get_marker() == expected["marker"]
+    finally:
+        plt.close(fig)
+
+
+@pytest.mark.parametrize("fmt", ["roo", "r?", "ro--?"])
+def test_unrecognized_components_still_raise(fmt):
+    with pytest.raises(ValueError, match="Unrecognized format components"):
+        mpl_styling(fmt, {}, {})
+
+
+def test_keyword_options_override_compact_marker():
+    assert mpl_styling("ro--", {"linewidth": 2}, {"marker": "x"}) == {
+        "color": "r",
+        "marker": "x",
+        "linestyle": "--",
+        "linewidth": 2,
+    }