KML write support

examples/kml.html

@@ -25,6 +25,11 @@
       <div class="row-fluid">
         <div class="span12">
           <div id="map" class="map"></div>
+          <div id="no-download" class="alert alert-error" style="display: none">
+            The "Export KML" functionality requires a browser that supports the
+            <a href="http://caniuse.com/#feat=download">link download</a> attribute.
+          </div>
+          <a id="export-kml" class="btn" download="map.kml"><i class="icon-download"></i>Export KML</a>
         </div>
       </div>
 

examples/kml.js

@@ -1,10 +1,14 @@
 goog.require('ol.Map');
 goog.require('ol.View2D');
+goog.require('ol.format.KML');
 goog.require('ol.layer.Tile');
 goog.require('ol.layer.Vector');
+goog.require('ol.proj');
 goog.require('ol.source.BingMaps');
 goog.require('ol.source.KML');
 
+var projection = ol.proj.get('EPSG:3857');
+
 var raster = new ol.layer.Tile({
   source: new ol.source.BingMaps({
     imagerySet: 'Aerial',
@@ -14,7 +18,7 @@ var raster = new ol.layer.Tile({
 
 var vector = new ol.layer.Vector({
   source: new ol.source.KML({
-    projection: 'EPSG:3857',
+    projection: projection,
     url: 'data/kml/2012-02-10.kml'
   })
 });
@@ -24,6 +28,7 @@ var map = new ol.Map({
   target: document.getElementById('map'),
   view: new ol.View2D({
     center: [876970.8463461736, 5859807.853963373],
+    projection: projection,
     zoom: 10
   })
 });
@@ -55,3 +60,31 @@ $(map.getViewport()).on('mousemove', function(evt) {
 map.on('click', function(evt) {
   displayFeatureInfo(evt.pixel);
 });
+
+var exportKMLElement = document.getElementById('export-kml');
+if ('download' in exportKMLElement) {
+  var vectorSource = /** @type {ol.source.Vector} */ (vector.getSource());
+  exportKMLElement.addEventListener('click', function(e) {
+    if (!exportKMLElement.href) {
+      var features = [];
+      vectorSource.forEachFeature(function(feature) {
+        var clone = feature.clone();
+        clone.setId(feature.getId());  // clone does not set the id
+        clone.getGeometry().transform(projection, 'EPSG:4326');
+        features.push(clone);
+      });
+      var node = new ol.format.KML().writeFeatures(features);
+      var string = new XMLSerializer().serializeToString(
+          /** @type {Node} */ (node));
+      var base64 = exampleNS.strToBase64(string);
+      exportKMLElement.href =
+          'data:application/vnd.google-earth.kml+xml;base64,' + base64;
+    }
+  }, false);
+} else {
+  var info = document.getElementById('no-download');
+  /**
+   * display error message
+   */
+  info.style.display = '';
+}

externs/example.js

@@ -5,5 +5,14 @@ var exampleNS;
 
 
 
-/** @interface */
+/**
+ * @return {string} Renderer type.
+ */
 exampleNS.getRendererFromQueryString = function() {};
+
+
+/**
+ * @param {string} str String.
+ * @return {string} Base64 string.
+ */
+exampleNS.strToBase64 = function(str) {};

resources/example-behaviour.js

@@ -84,3 +84,178 @@ exampleNS.getRendererFromQueryString = function() {
     return undefined;
   }
 };
+
+/*\
+|*|
+|*|  Base64 / binary data / UTF-8 strings utilities
+|*|
+|*|  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding
+|*|
+\*/
+
+/* Array of bytes to base64 string decoding */
+
+function b64ToUint6 (nChr) {
+
+  return nChr > 64 && nChr < 91 ?
+      nChr - 65
+    : nChr > 96 && nChr < 123 ?
+      nChr - 71
+    : nChr > 47 && nChr < 58 ?
+      nChr + 4
+    : nChr === 43 ?
+      62
+    : nChr === 47 ?
+      63
+    :
+      0;
+
+}
+
+function base64DecToArr (sBase64, nBlocksSize) {
+
+  var
+    sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""), nInLen = sB64Enc.length,
+    nOutLen = nBlocksSize ? Math.ceil((nInLen * 3 + 1 >> 2) / nBlocksSize) * nBlocksSize : nInLen * 3 + 1 >> 2, taBytes = new Uint8Array(nOutLen);
+
+  for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
+    nMod4 = nInIdx & 3;
+    nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 18 - 6 * nMod4;
+    if (nMod4 === 3 || nInLen - nInIdx === 1) {
+      for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
+        taBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;
+      }
+      nUint24 = 0;
+
+    }
+  }
+
+  return taBytes;
+}
+
+/* Base64 string to array encoding */
+
+function uint6ToB64 (nUint6) {
+
+  return nUint6 < 26 ?
+      nUint6 + 65
+    : nUint6 < 52 ?
+      nUint6 + 71
+    : nUint6 < 62 ?
+      nUint6 - 4
+    : nUint6 === 62 ?
+      43
+    : nUint6 === 63 ?
+      47
+    :
+      65;
+
+}
+
+function base64EncArr (aBytes) {
+
+  var nMod3 = 2, sB64Enc = "";
+
+  for (var nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
+    nMod3 = nIdx % 3;
+    if (nIdx > 0 && (nIdx * 4 / 3) % 76 === 0) { sB64Enc += "\r\n"; }
+    nUint24 |= aBytes[nIdx] << (16 >>> nMod3 & 24);
+    if (nMod3 === 2 || aBytes.length - nIdx === 1) {
+      sB64Enc += String.fromCharCode(uint6ToB64(nUint24 >>> 18 & 63), uint6ToB64(nUint24 >>> 12 & 63), uint6ToB64(nUint24 >>> 6 & 63), uint6ToB64(nUint24 & 63));
+      nUint24 = 0;
+    }
+  }
+
+  return sB64Enc.substr(0, sB64Enc.length - 2 + nMod3) + (nMod3 === 2 ? '' : nMod3 === 1 ? '=' : '==');
+
+}
+
+/* UTF-8 array to DOMString and vice versa */
+
+function UTF8ArrToStr (aBytes) {
+
+  var sView = "";
+
+  for (var nPart, nLen = aBytes.length, nIdx = 0; nIdx < nLen; nIdx++) {
+    nPart = aBytes[nIdx];
+    sView += String.fromCharCode(
+      nPart > 251 && nPart < 254 && nIdx + 5 < nLen ? /* six bytes */
+        /* (nPart - 252 << 32) is not possible in ECMAScript! So...: */
+        (nPart - 252) * 1073741824 + (aBytes[++nIdx] - 128 << 24) + (aBytes[++nIdx] - 128 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
+      : nPart > 247 && nPart < 252 && nIdx + 4 < nLen ? /* five bytes */
+        (nPart - 248 << 24) + (aBytes[++nIdx] - 128 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
+      : nPart > 239 && nPart < 248 && nIdx + 3 < nLen ? /* four bytes */
+        (nPart - 240 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
+      : nPart > 223 && nPart < 240 && nIdx + 2 < nLen ? /* three bytes */
+        (nPart - 224 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
+      : nPart > 191 && nPart < 224 && nIdx + 1 < nLen ? /* two bytes */
+        (nPart - 192 << 6) + aBytes[++nIdx] - 128
+      : /* nPart < 127 ? */ /* one byte */
+        nPart
+    );
+  }
+
+  return sView;
+
+}
+
+function strToUTF8Arr (sDOMStr) {
+
+  var aBytes, nChr, nStrLen = sDOMStr.length, nArrLen = 0;
+
+  /* mapping... */
+
+  for (var nMapIdx = 0; nMapIdx < nStrLen; nMapIdx++) {
+    nChr = sDOMStr.charCodeAt(nMapIdx);
+    nArrLen += nChr < 0x80 ? 1 : nChr < 0x800 ? 2 : nChr < 0x10000 ? 3 : nChr < 0x200000 ? 4 : nChr < 0x4000000 ? 5 : 6;
+  }
+
+  aBytes = new Uint8Array(nArrLen);
+
+  /* transcription... */
+
+  for (var nIdx = 0, nChrIdx = 0; nIdx < nArrLen; nChrIdx++) {
+    nChr = sDOMStr.charCodeAt(nChrIdx);
+    if (nChr < 128) {
+      /* one byte */
+      aBytes[nIdx++] = nChr;
+    } else if (nChr < 0x800) {
+      /* two bytes */
+      aBytes[nIdx++] = 192 + (nChr >>> 6);
+      aBytes[nIdx++] = 128 + (nChr & 63);
+    } else if (nChr < 0x10000) {
+      /* three bytes */
+      aBytes[nIdx++] = 224 + (nChr >>> 12);
+      aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
+      aBytes[nIdx++] = 128 + (nChr & 63);
+    } else if (nChr < 0x200000) {
+      /* four bytes */
+      aBytes[nIdx++] = 240 + (nChr >>> 18);
+      aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
+      aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
+      aBytes[nIdx++] = 128 + (nChr & 63);
+    } else if (nChr < 0x4000000) {
+      /* five bytes */
+      aBytes[nIdx++] = 248 + (nChr >>> 24);
+      aBytes[nIdx++] = 128 + (nChr >>> 18 & 63);
+      aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
+      aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
+      aBytes[nIdx++] = 128 + (nChr & 63);
+    } else /* if (nChr <= 0x7fffffff) */ {
+      /* six bytes */
+      aBytes[nIdx++] = 252 + /* (nChr >>> 32) is not possible in ECMAScript! So...: */ (nChr / 1073741824);
+      aBytes[nIdx++] = 128 + (nChr >>> 24 & 63);
+      aBytes[nIdx++] = 128 + (nChr >>> 18 & 63);
+      aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
+      aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
+      aBytes[nIdx++] = 128 + (nChr & 63);
+    }
+  }
+
+  return aBytes;
+
+}
+
+exampleNS.strToBase64 = function(str) {
+  return base64EncArr(strToUTF8Arr(str));
+};