Fix python3 stuff in test_image_overlay

Author: Martin Journois

folium/features.py

@@ -7,9 +7,11 @@
 """
 from jinja2 import Template
 import json
+import base64
 
 from .utilities import color_brewer, _parse_size, legend_scaler, _locations_mirror, _locations_tolist, write_png,\
     mercator_transform
+from .six import text_type, binary_type
 
 from .element import Element, Figure, JavascriptLink, CssLink, Div, MacroElement
 from .map import Map, TileLayer, Icon, Marker, Popup
@@ -576,16 +578,17 @@ def __init__(self, image, bounds, opacity=1., attribution=None, origin='upper',
             else:
                 fileformat = 'png'
             self.url = "data:image/{};base64,{}".format(fileformat,
-                                                   image.read().encode('base64'))
-        elif hasattr(image,'__iter__'):
+                                                   base64.b64encode(image.read()).decode('utf-8'))
+        elif (not (isinstance(image,text_type) or isinstance(image,binary_type))) and hasattr(image,'__iter__'):
             # We got an array-like object
             if mercator_project:
                 data = mercator_transform(image,
                                           [bounds[0][0], bounds[1][0]],
                                           origin=origin)
             else:
                 data = image
-            self.url = "data:image/png;base64," +write_png(data, origin=origin, colormap=colormap).encode('base64')
+            self.url = "data:image/png;base64," +\
+                base64.b64encode(write_png(data, origin=origin, colormap=colormap)).decode('utf-8')
         else:
             # We got an url
             self.url = json.loads(json.dumps(image))

folium/utilities.py

@@ -411,7 +411,7 @@ def write_png(data, origin='upper', colormap=None):
     assert array.shape == (height,width,nblayers)
 
     if nblayers==1:
-        array = np.array(map(colormap,array.ravel()))
+        array = np.array(list(map(colormap,array.ravel())))
         nblayers = array.shape[1]
         if nblayers not in [3,4]:
             raise ValueError("colormap must provide colors of"

tests/test_folium.py

@@ -15,6 +15,7 @@
 from jinja2 import Environment, PackageLoader
 import vincent
 import folium
+import base64
 from folium.six import PY3
 from folium.plugins import ScrollZoomToggler, MarkerCluster
 from folium.element import Html
@@ -656,7 +657,7 @@ def test_image_overlay(self):
         #with open('data.png', 'wb') as f:
         #    f.write(png_str)
         png = "data:image/png;base64,{}".format
-        inline_image_url = png(png_str.encode('base64').decode('utf-8'))
+        inline_image_url = png(base64.b64encode(png_str).decode('utf-8'))
 
         image_tpl = self.env.get_template('image_layer.js')
         image_name = 'Image_Overlay'