Just a small description of plugins, what they are, how they work, and how to implement one.
To undestand how plugins work, you have to know how Folium template is made. Basically, it is made of four parts :
divs are defined there.Now, a plugin is an object that inherits from folium.plugins.Plugin, whose goal is to write things into these four parts.
This is an example of plugin, that imports a Javascript library, defines a css class, creates a new div, defines a Javascript object and add it to the map.
from folium.plugins.plugin import Plugin
class MyPlugin(Plugin):
def __init__(self, data):
"""Creates a MyPlugin plugin to append into a map with
Map.add_plugin.
"""
super(MyPlugin, self).__init__() # We call Plugin.__init__.
# This will (in particular) define self.object_id as a random hexadecimal string (unique).
self.plugin_name = 'MyPlugin' # This will help to name variables in html and js.
def render_header(self, nb):
"""Generates the header part of the plugin."""
return """
<link rel="stylesheet" href="https://myplugin_stylesheet.css">
<script src="https://myplugin_script.js">
""" if nb==0 else ""
def render_css(self, nb):
"""Generates the css part of the plugin."""
return """
#myplugin {
color: #ff00ff,
width: 314px
};
"""
def render_html(self, nb):
"""Generates the html part of the plugin."""
return """
<div id="myplugin{id}"></div>
""".format(id = self.object_name)
def render_js(self, nb):
"""Generates the Javascript part of the plugin."""
return """
var MyPlugin_{id} = myplugin_script.someObject();
map.addLayer(MyPlugin_{id});
""".format(id = self.object_name)
Note that you may be willing to put on a map several instances of the same plugin. But you don't want the header to be written several times. This is why each method has a nb argument, that will be incremented at each instance's render.
Hence the line
if nb==0 else ""TODO : write something interesting here.