Add marker.transformed + test

Author: deep-jkl

lib/matplotlib/markers.py

@@ -236,7 +236,7 @@ def __init__(self, marker=_unset, fillstyle=None,
 
         fillstyle : str, default: :rc:`markers.fillstyle`
             One of 'full', 'left', 'right', 'bottom', 'top', 'none'.
-        
+
         transform : Affine2D, default: None
             User supplied transformation that will be combined with the
             native transformation of selected marker.
@@ -319,10 +319,10 @@ def _set_fillstyle(self, fillstyle):
         self._recache()
 
     def get_joinstyle(self):
-        return self._joinstyle
+        return self._user_joinstyle or self._joinstyle
 
     def get_capstyle(self):
-        return self._capstyle
+        return self._user_capstyle or self._capstyle
 
     def get_marker(self):
         return self._marker
@@ -414,6 +414,51 @@ def get_alt_transform(self):
     def get_snap_threshold(self):
         return self._snap_threshold
 
+    def get_user_transform(self):
+        """Return user supplied part of marker transform."""
+        if self._user_transform is not None:
+            return self._user_transform.frozen()
+
+    def transformed(self, transform:Affine2D):
+        """
+        Return new marker with combined transformation.
+
+        Parameters
+        ----------
+        transform : Affine2D, default: None
+            - transform will be combined with current user supplied transform.
+        """
+        new_marker = MarkerStyle(self)
+        if new_marker._user_transform is not None:
+            new_marker._user_transform += transform
+        else:
+            new_marker._user_transform = transform
+        return new_marker
+
+    def rotated(self, deg=None, rad=None):
+        """
+        Return new marker rotated by specified angle.
+
+        Parameters
+        ----------
+        deg : float, default: None
+
+        rad : float, default: None
+        """
+        if not ((deg is None) ^ (rad is None)):
+            raise Exception("Only one of deg or rad shall be used.")
+        
+        _transform = self._user_transform or Affine2D()
+
+        if deg is not None: 
+            _transform = _transform.rotate_deg(deg)
+        
+        if rad is not None:
+            _transform = _transform.rotate(rad)
+
+        new_marker = MarkerStyle(self)
+        new_marker._user_transform = _transform
+
     def _set_nothing(self):
         self._filled = False
 

lib/matplotlib/tests/test_marker.py

@@ -4,6 +4,7 @@
 from matplotlib._api.deprecation import MatplotlibDeprecationWarning
 from matplotlib.path import Path
 from matplotlib.testing.decorators import check_figures_equal
+from matplotlib.transforms import Affine2D
 
 import pytest
 
@@ -204,3 +205,13 @@ def test_marker_clipping(fig_ref, fig_test):
     ax_test.set(xlim=(-0.5, ncol), ylim=(-0.5, 2 * nrow))
     ax_ref.axis('off')
     ax_test.axis('off')
+
+@pytest.mark.parametrize("marker,transform,expected", [
+    (markers.MarkerStyle("o"), Affine2D().translate(1,1), Affine2D().translate(1,1)),
+    (markers.MarkerStyle("o", transform=Affine2D().translate(1,1)), Affine2D().translate(1,1), Affine2D().translate(2,2)),
+])
+def test_marker_transformed(marker, transform, expected):
+    new_marker = marker.transformed(transform)
+    assert new_marker is not marker
+    assert new_marker.get_user_transform() == expected
+    assert marker.get_user_transform() is not new_marker.get_user_transform()