marker cache api in node-mapnik

cache-api.js

// MarkerCache is a singleton so does not need to be created
var mc = mapnik.MarkerCache;

// size
// should always report `2` since there are `2` built-in markers (ellipse and arrow)
mc.size();

// keys
// should report the keys of the `2` built-in markers
> mc.keys();
['shape://arrow', 'shape://ellipse']

// clear
// will clear all markers except built-in markers
mc.clear();

// put
// can put either images or svg objects

// image
var image = mapnik.Image.open('./path/to/file.png');
mc.put('./path/to/file.png',image);

// svg
var svg = mapnik.SVG.open('./path/to/graphics.svg');
mc.put('./path/to/graphics.svg');

// can also load from strings and use custom key
var im_mem_image = mapnik.Image.fromString(png_buffer);
mc.put(crypto.createHash('md5').update(png_buffer).digest("hex"),in_mem_image);

// remove
// will remove a cache entry by key name and return true if successfully removed
var found = mc.remove('./path/to/file.png');

// get
// can get an Image or SVG object out of the cache
var image_copy = mc.get('./path/to/file.png');