net/systemeD/halcyon/connection/OSMConnection.as

   1 package net.systemeD.halcyon.connection {
   2
   3     import flash.events.*;
   4         import flash.net.*;
   5         import flash.utils.Dictionary;
   6         import flash.system.Security;
   7
   8         import net.systemeD.halcyon.ExtendedURLLoader;
   9         import net.systemeD.halcyon.Globals;
  10
  11         // Read-only connection from local files (for Halcyon)
  12
  13         // For a limited set of arbitrary files, invoke it like this:
  14         //              fo.addVariable("api","http://127.0.0.1/~richard/potlatch2");            // base URL
  15         //              fo.addVariable("connection","OSM");
  16         //              fo.addVariable("files","-1.5_-1.4_52.1_52.2.osm");
  17
  18         // For evenly arranged tiles, invoke it like this:
  19         //              fo.addVariable("api","http://127.0.0.1/~richard/potlatch2");            // base URL
  20         //              fo.addVariable("connection","OSM");
  21         //              fo.addVariable("tile_resolution","0.2");
  22         // and it'll then look for '-1.4_-1.2_52_52.2.osm', '-1.2_-1_52_52.2.osm', and so on
  23         // (this needs some more testing)
  24
  25         public class OSMConnection extends XMLBaseConnection {
  26
  27                 private var filemode:uint;
  28                 private static const NAMED:uint=0;
  29                 private static const TILED:uint=1;
  30                 // are we running from a limited set of files, or can we request tiles for any bbox?
  31
  32                 private var bboxes:Dictionary=new Dictionary();
  33                 private static const AVAILABLE:uint=0;
  34                 private static const LOADED:uint=1;
  35                 private static const LOADING:uint=2;
  36                 private static const UNAVAILABLE:uint=3;
  37                 // a hash of known files [left,right,top,bottom], and their current status
  38
  39                 private var tileResolution:Number;
  40                 // degree resolution for tiles (e.g. 0.2)
  41
  42                 private static const FILENAME:RegExp=/([\-\d\.]+)_([\-\d\.]+)_([\-\d\.]+)_([\-\d\.]+)\./i;
  43
  44                 public function OSMConnection() {
  45
  46                         if (Connection.policyURL!='')
  47                 Security.loadPolicyFile(Connection.policyURL);
  48
  49             tileResolution = Number(Connection.getParam("tile_resolution", "0.2"));
  50
  51                         var o:Object = new Object();
  52                         var files:String = Connection.getParam("files","");
  53                         if (files=="") {
  54                                 filemode=TILED;
  55                         } else {
  56                                 filemode=NAMED;
  57                                 for each (var file:String in files.split(/,/)) {
  58                                         if ((o=FILENAME.exec(file))) {
  59                                                 bboxes[[o[1],o[2],o[3],o[4]]]=AVAILABLE;
  60                                         }
  61                                 }
  62                         }
  63                 }
  64
  65                 override public function loadBbox(left:Number,right:Number,
  66                                                                 top:Number,bottom:Number):void {
  67                         var l:Number, r:Number, t:Number, b:Number, x:Number, y:Number, k:Array;
  68
  69                         // look through bboxes, assemble any within the requested bbox that are AVAILABLE
  70                         for (var box:* in bboxes) {
  71                                 k=box as Array;
  72                                 l=k[0]; r=k[1]; t=k[2]; b=k[3];
  73                                 if ( ( (left>=l && left<=r) || (right>=l && right<=r) || (left<l && right>r) ) &&
  74                                          ( (top>=b && top<=t) || (bottom>=b && bottom<=t) || (bottom<b && top>t) ) ) {
  75                                         // yay, it intersects
  76                                         if (bboxes[box]==AVAILABLE) { loadFile(box); }
  77                                 }
  78                         }
  79                         if (filemode==NAMED) { return; }
  80
  81                         // look through tiles for any areas that are not covered
  82                         for (x=roundDown(left, tileResolution); x<=roundUp(right, tileResolution); x+=tileResolution) {
  83                                 for (y=roundDown(bottom, tileResolution); y<=roundUp(top, tileResolution); y+=tileResolution) {
  84                                         k=[x,x+tileResolution,y,y+tileResolution];
  85                                         if (bboxes[k]) {
  86                                                 if (bboxes[k]==AVAILABLE) { loadFile(k); }
  87                                         } else {
  88                                                 loadFile(k);
  89                                         }
  90                                 }
  91                         }
  92                 }
  93
  94                 private function loadFile(box:Array):void {
  95                         Globals.vars.root.addDebug("called loadFile for "+box);
  96                         bboxes[box]=LOADING;
  97
  98             var mapRequest:URLRequest = new URLRequest(Connection.apiBaseURL+"/"+box[0]+"_"+box[1]+"_"+box[2]+"_"+box[3]+".osm");
  99                         var mapLoader:ExtendedURLLoader = new ExtendedURLLoader();
 100                         mapLoader.info['bbox']=box;
 101                         mapLoader.addEventListener(Event.COMPLETE, markMapLoaded);
 102                         mapLoader.addEventListener(IOErrorEvent.IO_ERROR, markMapUnloadable);
 103                         mapLoader.load(mapRequest);
 104                         dispatchEvent(new Event(LOAD_STARTED));
 105                 }
 106
 107                 private function markMapLoaded(e:Event):void {
 108                         bboxes[e.target.info['bbox']]=LOADED;
 109                         loadedMap(e);
 110                 }
 111
 112                 private function markMapUnloadable(e:Event):void {
 113                         bboxes[e.target.info['bbox']]=UNAVAILABLE;
 114                 }
 115
 116                 override public function purgeOutside(left:Number, right:Number, top:Number, bottom:Number):void {
 117                         // we don't purge in an OSMConnection
 118                 }
 119
 120                 private function roundUp(a:Number,i:Number):Number {
 121                         if (a/i==Math.floor(a/i)) { return a/i; }
 122                         return Math.floor(a/i+1)*i;
 123                 }
 124                 private function roundDown(a:Number,i:Number):Number {
 125                         return Math.floor(a/i)*i;
 126                 }
 127
 128         }
 129 }