Set plot_bgcolor to white by default when converting from matplotlib figure

Author: robertoffmoura

plotly/matplotlylib/renderer.py

@@ -87,6 +87,7 @@ def open_figure(self, fig, props):
             autosize=False,
             hovermode="closest",
         )
+        self.plotly_fig["layout"].template.layout.plot_bgcolor = "white"
         self.mpl_x_bounds, self.mpl_y_bounds = mpltools.get_axes_bounds(fig)
         margin = go.layout.Margin(
             l=int(self.mpl_x_bounds[0] * self.plotly_fig["layout"]["width"]),

plotly/matplotlylib/tests/test_renderer.py

@@ -84,3 +84,12 @@ def test_multiple_traces_native_legend():
     assert plotly_fig.data[0].mode == "lines"
     assert plotly_fig.data[1].mode == "markers"
     assert plotly_fig.data[2].mode == "lines+markers"
+
+
+def test_plot_bgcolor_defaults_to_white():
+    plt.figure()
+    plt.plot([0, 1], [0, 1])
+
+    plotly_fig = tls.mpl_to_plotly(plt.gcf())
+
+    assert plotly_fig.layout.template.layout.plot_bgcolor == "white"