Dynamic tiles clipping - adapted by zanarmstrong

index.html

<!DOCTYPE html>
<html>
<head>
	<meta charset=UTF-8 />
	<title>Dynamic tile clipping and more</title>

	<link rel="stylesheet" href="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.css" />
	<link href='https://api.tiles.mapbox.com/mapbox.js/plugins/leaflet-draw/v0.2.2/leaflet.draw.css' rel='stylesheet' />
	
	<script src="//d3js.org/d3.v3.min.js"></script>
	<script src="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
	<script src='https://api.tiles.mapbox.com/mapbox.js/plugins/leaflet-draw/v0.2.2/leaflet.draw.js'></script>
	<style>
		.dropdown-control {
			box-shadow: rgba(0, 0, 0, 0.65) 0px 1px 5px 0px;
			background-color: #fff;		
		}
		.dropdown-control > label {
			background-color: #fff;
			border-radius: 4px;
			padding: 4px;
			display: block;
		}
	</style>
</head>
<body>
	<div id="map" style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></div>
	<script src="dtc.js"></script>
	<!--SVG filters for map container -->
	<svg>
		<defs>
			<filter id="grayscale">
				<feColorMatrix type="saturate" values="0"/>
			</filter>
      <filter id="partial-grayscale">
				<feColorMatrix type="saturate" values="0.5"/>
			</filter>
			<filter id="saturate">
				<feColorMatrix type="saturate" values="10"/>
			</filter>
			<filter id="hue_rotate">
				<feColorMatrix type="hueRotate" values="180"/>
			</filter>
			<filter id="luminance_mask">
				<feColorMatrix type="luminanceToAlpha"/>
			</filter>
			<filter id="sepia">
				<feColorMatrix 
				type="matrix" 
				values=".343 .669 .119 0 0 
								.249 .626 .130 0 0
								.172 .334 .111 0 0
								.000 .000 .000 1 0 "/>
			</filter>
			</pattern>		
		</defs>
	</svg>		
</body>
</html>

LICENSE.txt

The MIT License (MIT)
 
Copyright (c) 2014 [KoGor](https://github.com/KoGor)
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

dtc.js

var osmUrl = 'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
	//stamenUrl = 'http://{s}.tile.stamen.com/toner/{z}/{x}/{y}.png',
	attrib = '&copy; Map tiles by <a href="http://stamen.com">Stamen Design</a>, under <a href="http://creativecommons.org/licenses/by/3.0">CC BY 3.0</a> | <a href="http://openstreetmap.org/copyright">OpenStreetMap</a> contributors',
	main = L.tileLayer(osmUrl, {maxZoom: 18, attribution: attrib}),
	map = new L.Map('map', {
		layers: [main],
		center: [55.7501, 37.6687],
		zoom: 11 
	}),
	overlay = L.tileLayer(osmUrl).addTo(map);
	overlay.getContainer().style.display = "none";
	main.getContainer().style.filter = "url(#sepia)";
	main.getContainer().style.WebkitFilter = "url(#sepia)";

//Convert Leaflet geometries to D3 geometries
function projectPoint(x, y) {
	var point = map.latLngToLayerPoint(new L.LatLng(y, x));
	this.stream.point(point.x, point.y);
};

//Initialize SVG layer in Leaflet (works for leaflet-0.7.3)
map._initPathRoot()

var transform = d3.geo.transform({point: projectPoint}),
	path = d3.geo.path().projection(transform);

var svg = d3.select(".leaflet-main-pane").select("svg"),
	// add "leaflet-zoom-hide" class to SVG container for turning off zoom
	defs = svg.append("defs"),
	filterGrayscale = defs.append("filter").attr("id", "grayscale");

//Blur filter params
filterGrayscale.append("feColorMatrix").attr("type", "saturate").attr("values", 0);


//Some extra controls

var filterDropdown = L.Control.extend({
	options: {
		position: 'topright'
	},
	
	onAdd: function (map) {
    	// create the control container with a particular class name
		var container = L.DomUtil.create('div', 'dropdown-control');
		
		// ... initialize other DOM elements, add listeners, etc.
		container.innerHTML = '<label>filter: <select><option selected>none</option><option>grayscale</option><option>partial-grayscale</option><option>saturate</option><option>hue_rotate</option><option>luminance_mask</option></select></label>';
		L.DomEvent
		.on(container.firstChild.firstElementChild, 'change', function(e) {
			var filterStyle = main.getContainer().style.filter;
			if (this.value != 'none') {
				main.getContainer().style.filter = 'url(#'+ this.value + ')';
				main.getContainer().style.WebkitFilter = 'url(#'+ this.value + ')';
			} else {
				main.getContainer().style.filter = 'none';
				main.getContainer().style.WebkitFilter = 'none';
			};
		});
		
		return container;
    }
});
	
map.addControl(new filterDropdown());