X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/3d906fe8c6303c00e399ce2dfecc3471959fbe6e..34b147266c397bb1318bbfefb48df1c704855843:/public/javascripts/site.js

diff --git a/public/javascripts/site.js b/public/javascripts/site.js
index 8f9d3a035..5340ea99e 100644
--- a/public/javascripts/site.js
+++ b/public/javascripts/site.js
@@ -1,6 +1,8 @@
-//Called as the user scrolls/zooms around.
-//Maniplate hrefs of the view tab and various other links
-function updatelinks(lon,lat,zoom,layers,minlon,minlat,maxlon,maxlat) {
+/*
+ * Called as the user scrolls/zooms around to aniplate hrefs of the
+ * view tab and various other links
+ */
+function updatelinks(lon,lat,zoom,layers,minlon,minlat,maxlon,maxlat, obj_type, obj_id) {
   var decimals = Math.pow(10, Math.floor(zoom/3));
   var node;
 
@@ -16,6 +18,9 @@ function updatelinks(lon,lat,zoom,layers,minlon,minlat,maxlon,maxlat) {
     if (layers) {
       args["layers"] = layers;
     }
+    if (obj_type && obj_id) {
+      args[obj_type] = obj_id;
+    }
     node.href = setArgs(node.href, args);
   }
 
@@ -82,6 +87,20 @@ function updatelinks(lon,lat,zoom,layers,minlon,minlat,maxlon,maxlat) {
       node.style.fontStyle = 'italic';
     }
   }
+
+  node = document.getElementById("shortlinkanchor");
+  if (node) {
+    var args = getArgs(node.href);
+    var code = makeShortCode(lat, lon, zoom);
+    // little hack. may the gods of hardcoding please forgive me, or 
+    // show me the Right way to do it.
+    if (layers && (layers != "B000FTF")) {
+      args["layers"] = layers;
+      node.href = setArgs("http://osm.org/go/" + code, args);
+    } else {
+      node.href = "http://osm.org/go/" + code;
+    }
+  }
 }
 
 function getArgs(url) {
@@ -104,6 +123,9 @@ function getArgs(url) {
   return args;
 }
 
+/*
+ * Called to set the arguments on a URL from the given hash.
+ */
 function setArgs(url, args) {
    var queryitems = new Array();
 
@@ -119,6 +141,9 @@ function setArgs(url, args) {
    return url.replace(/\?.*$/, "") + "?" + queryitems.join("&");
 }
 
+/*
+ * Called to get the arguments from a URL as a hash.
+ */
 function getStyle(el, property) {
   var style;
 
@@ -132,3 +157,52 @@ function getStyle(el, property) {
 
   return style;
 }
+
+/*
+ * Called to interpolate JavaScript variables in strings using a
+ * similar syntax to rails I18n string interpolation - the only
+ * difference is that [[foo]] is the placeholder syntax instead
+ * of {{foo}} which allows the same string to be processed by both
+ * rails and then later by javascript.
+ */
+function i18n(string, keys) {
+  for (var key in keys) {
+    var re_key = '\\[\\[' + key + '\\]\\]';
+    var re = new RegExp(re_key, "g");
+      
+    string = string.replace(re, keys[key]);
+  }
+   
+  return string;
+} 
+
+function makeShortCode(lat, lon, zoom) {
+    char_array = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_@";
+    var x = Math.round((lon + 180.0) * ((1 << 30) / 90.0));
+    var y = Math.round((lat +  90.0) * ((1 << 30) / 45.0));
+    // hack around the fact that JS apparently only allows 53-bit integers?!?
+    // note that, although this reduces the accuracy of the process, it's fine for
+    // z18 so we don't need to care for now.
+    var c1 = 0, c2 = 0;
+    for (var i = 31; i > 16; --i) {
+	c1 = (c1 << 1) | ((x >> i) & 1);
+	c1 = (c1 << 1) | ((y >> i) & 1);
+    }
+    for (var i = 16; i > 1; --i) {
+	c2 = (c2 << 1) | ((x >> i) & 1);
+	c2 = (c2 << 1) | ((y >> i) & 1);
+    }
+    var str = "";
+    for (var i = 0; i < Math.ceil((zoom + 8) / 3.0) && i < 5; ++i) {
+	digit = (c1 >> (24 - 6 * i)) & 0x3f;
+	str += char_array.charAt(digit);
+    }
+    for (var i = 5; i < Math.ceil((zoom + 8) / 3.0); ++i) {
+	digit = (c2 >> (24 - 6 * (i - 5))) & 0x3f;
+	str += char_array.charAt(digit);
+    }
+    for (var i = 0; i < ((zoom + 8) % 3); ++i) {
+	str += "=";
+    }
+    return str;
+}