Add Colormap parsing to curved-quiver (#369)

* add cmap parsing

* add unittest

* correct input str

Author: cvanelteren

ultraplot/axes/plot.py

@@ -1580,6 +1580,9 @@ def curved_quiver(
         density = _not_none(density, rc["curved_quiver.density"])
         arrows_at_end = _not_none(arrow_at_end, rc["curved_quiver.arrows_at_end"])
 
+        if cmap:
+            cmap = constructor.Colormap(cmap)
+
         solver = CurvedQuiverSolver(x, y, density)
         if zorder is None:
             zorder = mlines.Line2D.zorder

ultraplot/tests/test_plot.py

@@ -587,3 +587,33 @@ def test_curved_quiver_multicolor_lines():
     assert m.lines.get_array().size > 0  # we have colors set
     assert m.lines.get_cmap() is not None
     return fig
+
+
+@pytest.mark.mpl_image_compare
+@pytest.mark.parametrize(
+    "cmap",
+    (
+        "k",  # color
+        "viridis",  # built-in
+        "viko",  # bundled with ultraplot
+    ),
+)
+def test_curved_quiver_color_and_cmap(rng, cmap):
+    """
+    Check that we can pass colors or colormaps
+    """
+    x = np.linspace(0, 1, 5)
+    y = np.linspace(0, 1, 5)
+    X, Y = np.meshgrid(x, y)
+    U = np.ones_like(X)
+    V = np.ones_like(Y)
+
+    # Deal with color or cmap
+    color = rng.random(X.shape)
+    if cmap == "k":
+        cmap = None
+        color = "k"
+
+    fig, ax = uplt.subplots()
+    ax.curved_quiver(X, Y, U, V, color=color, cmap=cmap)
+    return fig