refactor ImageOverlay

Author: ocefpaf

examples/GeodedeticImageOverlay.ipynb

@@ -5,73 +5,13 @@
 import json
 
 from branca.element import Element, Figure
-from branca.utilities import image_to_url
 
 from folium.map import Layer
+from folium.utilities import image_to_url, mercator_transform
 
 from jinja2 import Template
 
 
-def mercator_transform(data, lat_bounds, origin='upper', height_out=None):
-    """
-    Transforms an image computed in (longitude,latitude) coordinates into
-    the a Mercator projection image.
-
-    Parameters
-    ----------
-
-    data: numpy array or equivalent list-like object.
-        Must be NxM (mono), NxMx3 (RGB) or NxMx4 (RGBA)
-
-    lat_bounds : length 2 tuple
-        Minimal and maximal value of the latitude of the image.
-        Bounds must be between -85.051128779806589 and 85.051128779806589
-        otherwise they will be clipped to that values.
-
-    origin : ['upper' | 'lower'], optional, default 'upper'
-        Place the [0,0] index of the array in the upper left or lower left
-        corner of the axes.
-
-    height_out : int, default None
-        The expected height of the output.
-        If None, the height of the input is used.
-
-    See https://en.wikipedia.org/wiki/Web_Mercator for more details.
-
-    """
-    import numpy as np
-
-    def mercator(x):
-        return np.arcsinh(np.tan(x*np.pi/180.))*180./np.pi
-
-    array = np.atleast_3d(data).copy()
-    height, width, nblayers = array.shape
-
-    lat_min = max(lat_bounds[0], -85.051128779806589)
-    lat_max = min(lat_bounds[1], 85.051128779806589)
-    if height_out is None:
-        height_out = height
-
-    # Eventually flip the image
-    if origin == 'upper':
-        array = array[::-1, :, :]
-
-    lats = (lat_min + np.linspace(0.5/height, 1.-0.5/height, height) *
-            (lat_max-lat_min))
-    latslats = (mercator(lat_min) +
-                np.linspace(0.5/height_out, 1.-0.5/height_out, height_out) *
-                (mercator(lat_max)-mercator(lat_min)))
-
-    out = np.zeros((height_out, width, nblayers))
-    for i in range(width):
-        for j in range(nblayers):
-            out[:, i, j] = np.interp(latslats, mercator(lats),  array[:, i, j])
-
-    # Eventually flip the image.
-    if origin == 'upper':
-        out = out[::-1, :, :]
-    return out
-
 
 class ImageOverlay(Layer):
     """
@@ -91,47 +31,56 @@ class ImageOverlay(Layer):
         Image bounds on the map in the form [[lat_min, lon_min],
         [lat_max, lon_max]]
     opacity: float, default Leaflet's default (1.0)
-    attr: string, default Leaflet's default ("")
-    origin : ['upper' | 'lower'], optional, default 'upper'
+    alt: string, default Leaflet's default ('')
+    origin: ['upper' | 'lower'], optional, default 'upper'
         Place the [0,0] index of the array in the upper left or
         lower left corner of the axes.
-    colormap : callable, used only for `mono` image.
+    colormap: callable, used only for `mono` image.
         Function of the form [x -> (r,g,b)] or [x -> (r,g,b,a)]
         for transforming a mono image into RGB.
         It must output iterables of length 3 or 4,
         with values between 0 and 1.
-        Hint : you can use colormaps from `matplotlib.cm`.
-    mercator_project : bool, default False.
+        Hint: you can use colormaps from `matplotlib.cm`.
+    mercator_project: bool, default False.
         Used only for array-like image.  Transforms the data to
         project (longitude, latitude) coordinates to the
         Mercator projection.
         Beware that this will only work if `image` is an array-like
         object.
+    pixelated: bool, default True
+        Sharp sharp/crips (True) or aliased corners (False).
+
+    See http://leafletjs.com/reference-1.2.0.html#imageoverlay for more options.
 
     """
-    def __init__(self, image, bounds, opacity=1., attr=None,
-                 origin='upper', colormap=None, mercator_project=False,
-                 overlay=True, control=True, pixelated=True):
-        super(ImageOverlay, self).__init__(overlay=overlay, control=control)
+    def __init__(self, image, bounds, origin='upper', colormap=None,
+                 mercator_project=False, overlay=True, control=True,
+                 pixelated=True, name=None, **kwargs):
+        super(ImageOverlay, self).__init__(overlay=overlay, control=control, name=name)  # noqa
+
+        options = {
+            'opacity': kwargs.pop('opacity', 1.),
+            'alt': kwargs.pop('alt', ''),
+            'interactive': kwargs.pop('interactive', False),
+            'crossOrigin': kwargs.pop('cross_origin', False),
+            'errorOverlayUrl': kwargs.pop('error_overlay_url', ''),
+            'zIndex': kwargs.pop('zindex', 1),
+            'className': kwargs.pop('class_name', ''),
+        }
         self._name = 'ImageOverlay'
-        self.overlay = overlay
         self.pixelated = pixelated
 
         if mercator_project:
-            image = mercator_transform(image,
-                                       [bounds[0][0], bounds[1][0]],
-                                       origin=origin)
+            image = mercator_transform(
+                image,
+                [bounds[0][0],
+                 bounds[1][0]],
+                origin=origin)
 
         self.url = image_to_url(image, origin=origin, colormap=colormap)
 
         self.bounds = json.loads(json.dumps(bounds))
-        options = {
-            'opacity': opacity,
-            'attribution': attr,
-        }
-        self.options = json.dumps({key: val for key, val
-                                   in options.items() if val},
-                                  sort_keys=True)
+        self.options = json.dumps(options, sort_keys=True, indent=2)
         self._template = Template(u"""
             {% macro script(this, kwargs) %}
                 var {{this.get_name()}} = L.imageOverlay(
@@ -160,7 +109,7 @@ def render(self, **kwargs):
         </style>"""
 
         if self.pixelated:
-            figure.header.add_child(Element(pixelated), name='leaflet-image-layer')
+            figure.header.add_child(Element(pixelated), name='leaflet-image-layer')  # noqa
 
     def _get_self_bounds(self):
         """