FIX: Allow kwarg aliases in triplot

Co-authored-by: Elliott Sales de Andrade <[email protected]>

Author: gajendra0180

lib/matplotlib/tests/test_triangulation.py

@@ -9,7 +9,7 @@
 import matplotlib.pyplot as plt
 import matplotlib.tri as mtri
 from matplotlib.path import Path
-from matplotlib.testing.decorators import image_comparison
+from matplotlib.testing.decorators import image_comparison, check_figures_equal
 
 
 def test_delaunay():
@@ -1177,3 +1177,12 @@ def test_tricontourset_reuse():
     assert tcs2._contour_generator != tcs1._contour_generator
     tcs3 = ax.tricontour(tcs1, z)
     assert tcs3._contour_generator == tcs1._contour_generator
+
+
+@check_figures_equal()
+def test_triplot_with_ls(fig_test, fig_ref):
+    x = [0, 2, 1]
+    y = [0, 0, 1]
+    data = [[0, 1, 2]]
+    fig_test.subplots().triplot(x, y, data, ls='--')
+    fig_ref.subplots().triplot(x, y, data, linestyle='--')

lib/matplotlib/tri/triplot.py

@@ -1,5 +1,7 @@
 import numpy as np
 from matplotlib.tri.triangulation import Triangulation
+import matplotlib.cbook as cbook
+import matplotlib.lines as mlines
 
 
 def triplot(ax, *args, **kwargs):
@@ -42,11 +44,11 @@ def triplot(ax, *args, **kwargs):
     linestyle, marker, color = matplotlib.axes._base._process_plot_format(fmt)
 
     # Insert plot format string into a copy of kwargs (kwargs values prevail).
-    kw = kwargs.copy()
+    kw = cbook.normalize_kwargs(kwargs, mlines.Line2D)
     for key, val in zip(('linestyle', 'marker', 'color'),
                         (linestyle, marker, color)):
         if val is not None:
-            kw[key] = kwargs.get(key, val)
+            kw.setdefault(key, val)
 
     # Draw lines without markers.
     # Note 1: If we drew markers here, most markers would be drawn more than