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https://github.com/protomaps/PMTiles.git
synced 2026-02-04 02:41:09 +00:00
add leaflet example, js implementation
This commit is contained in:
Brandon Liu
30
examples/leaflet.html
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30
examples/leaflet.html
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@@ -0,0 +1,30 @@
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<html>
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<head>
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</head>
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<head>
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<meta charset="utf-8" />
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<link rel="stylesheet" href="https://unpkg.com/leaflet@1.6.0/dist/leaflet.css"/>
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<script src="https://unpkg.com/leaflet@1.6.0/dist/leaflet.js"></script>
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<script src="../js/pmtiles.js"></script>
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<style>
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body, #map {
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height:100vh;
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margin:0px;
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}
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</style>
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</head>
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<body>
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<div id="map"></div>
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<script>
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const map = L.map('map')
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const ready = metadata => {
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map.options.maxZoom = +metadata.maxzoom
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const b = metadata.bounds.split(',')
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map.fitBounds([[+b[1],+b[0]],[+b[3],+b[2]]],{maxZoom:+metadata.maxzoom})
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}
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const p = new pmtiles.PMTiles('http://localhost:8500/example.pmtiles',ready);
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p.leafletLayer().addTo(map)
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</script>
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</body>
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</html>
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137
js/pmtiles.js
137
js/pmtiles.js
@@ -1,11 +1,140 @@
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(function (root, factory) {
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if (typeof define === 'function' && define.amd) {
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define([], factory);
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define([], factory)
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} else if (typeof module === 'object' && module.exports) {
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module.exports = factory();
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module.exports = factory()
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} else {
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root.pmtiles = factory();
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root.pmtiles = factory()
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}
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}(typeof self !== 'undefined' ? self : this, function () {
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return {pmtiles:true};
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const getUint24 = (dataview, pos) => {
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return (dataview.getUint16(pos+1,true) << 8) + dataview.getUint8(pos,true);
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}
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const getUint48 = (dataview, pos) => {
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return (dataview.getUint32(pos+2,true) << 16) + dataview.getUint16(pos,true);
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}
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const parseHeader = dataview => {
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var magic = dataview.getUint16(0,true)
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// assert that the magic number (2 bytes) matches 19792
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var version = dataview.getUint16(2,true)
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var json_size = dataview.getUint32(4,true)
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var root_entries = dataview.getUint16(8,true)
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return {version:version,json_size:json_size,root_entries:root_entries}
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}
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const bytesToMap = dataview => {
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let m = new Map()
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for (var i = 0; i < dataview.byteLength; i+=17) {
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var z_raw = dataview.getUint8(i,true)
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var z = z_raw & 127
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var is_dir = z_raw >> 7
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var x = getUint24(dataview,i+1)
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var y = getUint24(dataview,i+4)
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var offset = getUint48(dataview,i+7)
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var length = dataview.getUint32(i+13,true)
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m.set(z + '_' + x + '_' + y,[offset,length,is_dir])
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}
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return m
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}
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class PMTiles {
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constructor(url,ready) {
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this.url = url
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this.apex = fetch(this.url,{method:'HEAD',headers:{'Range':'bytes=0-511999'}}).then(resp => {
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if (resp.status == 206) { // this does not work on Azure, it returns 200 instead of 206
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console.log("Check succeeded: server supports byte ranges")
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return fetch(this.url,{headers:{'Range':'bytes=0-511999'}}).then(resp => {
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return resp.arrayBuffer()
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}).then(buf => {
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const header = parseHeader(new DataView(buf,0,10))
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var dec = new TextDecoder("utf-8")
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if (ready) {
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ready(JSON.parse(dec.decode(new DataView(buf,10,header.json_size))))
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}
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return bytesToMap(new DataView(buf,10+header.json_size,17*header.root_entries))
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})
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}
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})
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// TODO make this LRU
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this.leaves = new Map()
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this.outstanding_requests = new Map()
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}
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getLeaf = tilestr => {
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return new Promise((resolve,reject) => {
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if (this.leaves.has(tilestr)) {
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resolve(this.leaves.get(tilestr))
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} else if (this.outstanding_requests.has(tilestr)) {
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this.outstanding_requests.get(tilestr).push(resolve)
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} else {
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this.outstanding_requests.set(tilestr,[])
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this.apex.then(apex_map => {
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if (apex_map.has(tilestr)) {
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var val = apex_map.get(tilestr)
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if (val[2] == 1) { // it is a directory
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fetch(this.url, {headers:{'range':'bytes=' + val[0] + '-' + (val[0] + val[1]-1)}}).then(resp => {
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return resp.arraybuffer()
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}).then(buf => {
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var map = bytestomap(buf,val[1]/17)
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this.leaves.set(tilestr,map)
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resolve(map)
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this.outstanding_requests.get(tilestr).foreach(f => {
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f(map)
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})
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console.log("leaves: ", this.leaves.size)
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})
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}
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}
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})
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}
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})
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}
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leafletLayer = options => {
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const self = this
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var cls = L.GridLayer.extend({
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createTile: function(coords, done){
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var tile = document.createElement('img');
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var error
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self.apex.then(map => {
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var strid = coords.z + '_' + coords.x + '_' + coords.y
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if (map.has(strid)) {
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var val = map.get(strid)
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fetch(self.url,{headers:{'Range':'bytes=' + val[0] + '-' + (val[0]+val[1]-1)}}).then(resp => {
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return resp.arrayBuffer()
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}).then(buf => {
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var blob = new Blob( [buf], { type: "image/png" } );
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var imageUrl = window.URL.createObjectURL(blob);
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tile.src = imageUrl;
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done(error,tile)
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})
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}
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})
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return tile;
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},
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_removeTile: function (key) {
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var tile = this._tiles[key]
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if (!tile) { return }
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tile.el.width = 0
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tile.el.height = 0
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tile.el.deleted = true
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L.DomUtil.remove(tile.el)
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delete this._tiles[key]
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this.fire('tileunload', {
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tile: tile.el,
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coords: this._keyToTileCoords(key)
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})
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},
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})
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return new cls()
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}
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}
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return {PMTiles:PMTiles}
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}));
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