True if Canvas is used for vector rendering (Android 2). You can also force
this by setting global variable L_PREFER_CANVAS to true before the Leaflet
include on your page — sometimes it can increase performance dramatically
when rendering thousands of circle markers, but currently suffers from
a bug that causes removing such layers to be extremely slow.
publicstatic CLIP_PADDING:number
How much to extend the clip area around the map view (relative to its size,
e.g. 0.5 is half the screen in each direction). Smaller values mean that you
will see clipped ends of paths while you're dragging the map, and bigger values
decrease drawing performance.
publicstatic SVG:boolean
True if SVG is used for vector rendering (true for most modern browsers).
publicstatic VML:boolean
True if VML is used for vector rendering (IE 6-8).
Should contain code that creates DOM elements for the overlay, adds them
to map panes where they should belong and puts listeners on relevant map events.
Called on map.addLayer(layer).
Should contain all clean up code that removes the overlay's elements from
the DOM and removes listeners previously added in onAdd. Called on map.removeLayer(layer).