Fix issue when converting matplotlib lines+markers legend to plotly

Author: robertoffmoura

plotly/matplotlylib/renderer.py

@@ -371,6 +371,12 @@ def draw_legend_shapes(self, mode, shape, **props):
                 x1 = props["data"][1][0]
                 y1 = props["data"][1][1]
 
+                lines_shape = shape.copy()
+                ignored_props = ["symbol", "size"]
+                for prop in ignored_props:
+                    if prop in lines_shape:
+                        lines_shape.pop(prop)
+
                 legend_shape = go.layout.Shape(
                     type=mode,
                     xref="paper",
@@ -379,7 +385,7 @@ def draw_legend_shapes(self, mode, shape, **props):
                     y0=y + 0.02,
                     x1=x1,
                     y1=y1 + 0.02,
-                    **shape,
+                    **lines_shape,
                 )
             else:
                 self.msg += "not sure how to handle this element\n"

plotly/matplotlylib/tests/__init__.py

@@ -0,0 +1,4 @@
+import matplotlib
+
+matplotlib.use("Agg")
+import matplotlib.pyplot as plt

plotly/matplotlylib/tests/test_renderer.py

@@ -0,0 +1,18 @@
+import plotly.tools as tls
+
+from . import plt
+
+def test_lines_markers_legend_plot():
+    x = [0, 1]
+    y = [0, 1]
+    label = "label"
+    plt.figure()
+    plt.plot(x, y, "o-", label=label)
+    plt.legend()
+
+    plotly_fig = tls.mpl_to_plotly(plt.gcf())
+
+    assert plotly_fig.data[0].mode == "lines+markers"
+    assert plotly_fig.data[0].x == tuple(x)
+    assert plotly_fig.data[0].y == tuple(y)
+    assert plotly_fig.data[0].name == "label"