@@ -7,8 +7,6 @@

 # http://kwant-project.org/authors.

 import numpy as np

-from matplotlib.colors import ListedColormap

-

 kr_data = [[ 0.98916316, 0.98474381, 0.99210697],

            [ 0.98723538, 0.98138853, 0.98740721],

@@ -271,4 +269,4 @@ kr_data = [[ 0.98916316, 0.98474381, 0.99210697],

 kr_data = np.array(kr_data)

 kr_data = np.clip(kr_data / kr_data[0], 0, 1)

-kwant_red = ListedColormap(kr_data, name="kwant red")

+kwant_red = kr_data

@@ -35,7 +35,10 @@ try:

     from matplotlib.figure import Figure

     from matplotlib import collections

     from . import _colormaps

+    from matplotlib.colors import ListedColormap

     mpl_available = True

+    kwant_red_matplotlib = ListedColormap(_colormaps.kwant_red,

+                                          name="kwant red")

     try:

         from mpl_toolkits import mplot3d

         has3d = True

@@ -53,7 +56,13 @@ try:

     import plotly.offline as plotly_module

     import plotly.graph_objs as plotly_graph_objs

     init_notebook_mode_set = False

+    from . import _colormaps

     plotly_available = True

+

+    _cmap_plotly = 255 * _colormaps.kwant_red

+    _cmap_levels = np.linspace(0, 1, len(_cmap_plotly))

+    kwant_red_plotly = [(level, 'rgb({},{},{})'.format(*rgb))

+                        for level, rgb in zip(_cmap_levels, _cmap_plotly)]

 except ImportError:

     warnings.warn("plotly is not available, if other backends are unavailable,"

                   " only iterator-providing functions will work",

@@ -353,3 +362,14 @@ if mpl_available:

                     self.set_linewidths(self.linewidths_orig2 * factor)

                 super().draw(renderer)

+

+if plotly_available:

+    def matplotlib_to_plotly_cmap(cmap, pl_entries):

+        h = 1.0/(pl_entries-1)

+        pl_colorscale = []

+

+        for k in range(pl_entries):

+            C = map(np.uint8, np.array(cmap(k*h)[:3])*255)

+            pl_colorscale.append([k*h, 'rgb'+str((C[0], C[1], C[2]))])

+

+        return pl_colorscale

@@ -1367,7 +1367,7 @@ def map(sys, value, colorbar=True, cmap=None, vmin=None, vmax=None, a=None,

         fig = None

     if cmap is None:

-        cmap = _p._colormaps.kwant_red

+        cmap = _p.kwant_red_matplotlib

     # Calculate the min/max bounds for the colormap.

     # User-provided values take precedence.

@@ -2197,7 +2197,7 @@ def streamplot(field, box, cmap=None, bgcolor=None, linecolor='k',

     if bgcolor is None:

         if cmap is None:

-            cmap = _p._colormaps.kwant_red

+            cmap = _p.kwant_red_matplotlib

         cmap = _p.matplotlib.cm.get_cmap(cmap)

         bgcolor = cmap(0)[:3]

     elif cmap is not None:

@@ -2307,7 +2307,7 @@ def scalarplot(field, box,

         raise ValueError("Only 2D field can be plotted.")

     if cmap is None:

-        cmap = _p._colormaps.kwant_red

+        cmap = _p.kwant_red_matplotlib

     cmap = _p.matplotlib.cm.get_cmap(cmap)

     if ax is None: