Created
October 7, 2016 10:07
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Leaflet GridLayer example with Canvas
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <title>GridLayer Test</title> | |
| <meta charset="utf-8" /> | |
| <link rel="stylesheet" href="https://unpkg.com/[email protected]/dist/leaflet.css" /> | |
| <style> | |
| body { | |
| padding: 0; | |
| margin: 0; | |
| } | |
| html, body, #map { | |
| height: 100%; | |
| width: 100%; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <div id="map"></div> | |
| <script src="https://unpkg.com/[email protected]/dist/leaflet.js"></script> | |
| <script> | |
| var map = new L.Map('map', { center: [10, 0], zoom: 2}); | |
| var tiles = new L.GridLayer(); | |
| tiles.createTile = function(coords) { | |
| var tile = L.DomUtil.create('canvas', 'leaflet-tile'); | |
| var ctx = tile.getContext('2d'); | |
| var size = this.getTileSize() | |
| tile.width = size.x | |
| tile.height = size.y | |
| // calculate projection coordinates of top left tile pixel | |
| var nwPoint = coords.scaleBy(size) | |
| // calculate geographic coordinates of top left tile pixel | |
| var nw = map.unproject(nwPoint, coords.z) | |
| ctx.fillStyle = 'white'; | |
| ctx.fillRect(0, 0, size.x, 50); | |
| ctx.fillStyle = 'black'; | |
| ctx.fillText('x: ' + coords.x + ', y: ' + coords.y + ', zoom: ' + coords.z, 20, 20); | |
| ctx.fillText('lat: ' + nw.lat + ', lon: ' + nw.lng, 20, 40); | |
| ctx.strokeStyle = 'red'; | |
| ctx.beginPath(); | |
| ctx.moveTo(0, 0); | |
| ctx.lineTo(size.x-1, 0); | |
| ctx.lineTo(size.x-1, size.y-1); | |
| ctx.lineTo(0, size.y-1); | |
| ctx.closePath(); | |
| ctx.stroke(); | |
| return tile; | |
| } | |
| L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', { | |
| attribution: 'Map data © <a href="http://www.osm.org">OpenStreetMap</a>' | |
| }).addTo(map) | |
| tiles.addTo(map) | |
| </script> | |
| </body> | |
| </html> |
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