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     /**
  12     * Read-only connection from local OSM-XML format (.osm) files.
  13     * This is used by Halcyon; Potlatch 2 needs a full server connection
  14     * of the type provided by XMLConnection
  15     */
  16
  17         // For a limited set of arbitrary files, invoke it like this:
  18         //              fo.addVariable("api","http://127.0.0.1/~richard/potlatch2");            // base URL
  19         //              fo.addVariable("connection","OSM");
  20         //              fo.addVariable("files","-1.5_-1.4_52.1_52.2.osm");
  21
  22         // For evenly arranged tiles, invoke it like this:
  23         //              fo.addVariable("api","http://127.0.0.1/~richard/potlatch2");            // base URL
  24         //              fo.addVariable("connection","OSM");
  25         //              fo.addVariable("tile_resolution","0.2");
  26         // and it'll then look for '-1.4_-1.2_52_52.2.osm', '-1.2_-1_52_52.2.osm', and so on
  27         // (this needs some more testing)
  28
  29         public class OSMConnection extends XMLBaseConnection {
  30
  31                 private var filemode:uint;
  32                 private static const NAMED:uint=0;
  33                 private static const TILED:uint=1;
  34                 // are we running from a limited set of files, or can we request tiles for any bbox?
  35
  36                 private var bboxes:Dictionary=new Dictionary();
  37                 private static const AVAILABLE:uint=0;
  38                 private static const LOADED:uint=1;
  39                 private static const LOADING:uint=2;
  40                 private static const UNAVAILABLE:uint=3;
  41                 // a hash of known files [left,right,top,bottom], and their current status
  42
  43                 private var tileResolution:Number;
  44                 // degree resolution for tiles (e.g. 0.2)
  45
  46                 private static const FILENAME:RegExp=/([\-\d\.]+)_([\-\d\.]+)_([\-\d\.]+)_([\-\d\.]+)\./i;
  47
  48                 public function OSMConnection() {
  49
  50                         if (Connection.policyURL!='')
  51                 Security.loadPolicyFile(Connection.policyURL);
  52
  53             tileResolution = Number(Connection.getParam("tile_resolution", "0.2"));
  54
  55                         var o:Object = new Object();
  56                         var files:String = Connection.getParam("files","");
  57                         if (files=="") {
  58                                 filemode=TILED;
  59                         } else {
  60                                 filemode=NAMED;
  61                                 for each (var file:String in files.split(/,/)) {
  62                                         if ((o=FILENAME.exec(file))) {
  63                                                 bboxes[[o[1],o[2],o[3],o[4]]]=AVAILABLE;
  64                                         }
  65                                 }
  66                         }
  67                 }
  68
  69                 override public function loadBbox(left:Number,right:Number,
  70                                                                 top:Number,bottom:Number):void {
  71                         var l:Number, r:Number, t:Number, b:Number, x:Number, y:Number, k:Array;
  72
  73                         // look through bboxes, assemble any within the requested bbox that are AVAILABLE
  74                         for (var box:* in bboxes) {
  75                                 k=box as Array;
  76                                 l=k[0]; r=k[1]; t=k[2]; b=k[3];
  77                                 if ( ( (left>=l && left<=r) || (right>=l && right<=r) || (left<l && right>r) ) &&
  78                                          ( (top>=b && top<=t) || (bottom>=b && bottom<=t) || (bottom<b && top>t) ) ) {
  79                                         // yay, it intersects
  80                                         if (bboxes[box]==AVAILABLE) { loadFile(box); }
  81                                 }
  82                         }
  83                         if (filemode==NAMED) { return; }
  84
  85                         // look through tiles for any areas that are not covered
  86                         for (x=roundDown(left, tileResolution); x<=roundUp(right, tileResolution); x+=tileResolution) {
  87                                 for (y=roundDown(bottom, tileResolution); y<=roundUp(top, tileResolution); y+=tileResolution) {
  88                                         k=[x,x+tileResolution,y,y+tileResolution];
  89                                         if (bboxes[k]) {
  90                                                 if (bboxes[k]==AVAILABLE) { loadFile(k); }
  91                                         } else {
  92                                                 loadFile(k);
  93                                         }
  94                                 }
  95                         }
  96                 }
  97
  98                 private function loadFile(box:Array):void {
  99                         Globals.vars.root.addDebug("called loadFile for "+box);
 100                         bboxes[box]=LOADING;
 101
 102             var mapRequest:URLRequest = new URLRequest(Connection.apiBaseURL+"/"+box[0]+"_"+box[1]+"_"+box[2]+"_"+box[3]+".osm");
 103                         var mapLoader:ExtendedURLLoader = new ExtendedURLLoader();
 104                         mapLoader.info['bbox']=box;
 105                         mapLoader.addEventListener(Event.COMPLETE, markMapLoaded);
 106                         mapLoader.addEventListener(IOErrorEvent.IO_ERROR, markMapUnloadable);
 107                         mapLoader.load(mapRequest);
 108                         dispatchEvent(new Event(LOAD_STARTED));
 109                 }
 110
 111                 private function markMapLoaded(e:Event):void {
 112                         bboxes[e.target.info['bbox']]=LOADED;
 113                         loadedMap(e);
 114                 }
 115
 116                 private function markMapUnloadable(e:Event):void {
 117                         bboxes[e.target.info['bbox']]=UNAVAILABLE;
 118                 }
 119
 120                 override public function purgeOutside(left:Number, right:Number, top:Number, bottom:Number):void {
 121                         // we don't purge in an OSMConnection
 122                 }
 123
 124                 private function roundUp(a:Number,i:Number):Number {
 125                         if (a/i==Math.floor(a/i)) { return a/i; }
 126                         return Math.floor(a/i+1)*i;
 127                 }
 128                 private function roundDown(a:Number,i:Number):Number {
 129                         return Math.floor(a/i)*i;
 130                 }
 131
 132         }
 133 }