]> git.openstreetmap.org Git - rails.git/blobdiff - public/javascripts/tile.js
more basic framework
[rails.git] / public / javascripts / tile.js
diff --git a/public/javascripts/tile.js b/public/javascripts/tile.js
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+// June 20th 2005 http://civicactions.net anselm@hook.org public domain version 0.5
+
+//
+// miscellaneous
+//
+
+var netscape = ( document.getElementById && !document.all ) || document.layers;
+var defaultEngine = null; // xxx for firefox keyboard events.
+
+var PI = 3.14159265358979323846;
+
+var lat_range = PI, lon_range = PI;
+
+//
+// Utility - get div position - may not be accurate
+//
+
+function getCSSPositionX(parent) 
+{
+    var offset = parent.x ? parseInt(parent.x) : 0;
+    offset += parent.style.left ? parseInt(parent.style.left) : 0;
+    for(var node = parent; node ; node = node.offsetParent ) 
+       { 
+               offset += node.offsetLeft; 
+       }
+    return offset;
+}
+
+function getCSSPositionY(parent) 
+{
+    var offset = parent.y ? parseInt(parent.y) : 0;
+    offset += parent.style.top ? parseInt(parent.style.top) : 0;
+    for(var node = parent; node ; node = node.offsetParent ) 
+       { 
+               offset += node.offsetTop; 
+       }
+    return offset;
+}
+
+///
+/// initialize a new tile engine object
+/// usage: var engine = new tile_engine_new(parentdiv,stylehints,wmssource,lon,lat,zoom,optional width, optional height)
+///
+function tile_engine_new(parentname,hints,feedurl,url,lon,lat,zoom,w,h) 
+{
+    // NW geocoder removed for now
+
+       this.timestamp = new Date().getTime();
+       this.urlAttr = new Array();
+
+    // NW Removed navigation buttons entirely for flexibility    
+
+    this.lonPerPixel = function()
+            { return (this.lon_quant/this.scale)/this.tilewidth; }
+
+    this.latPerPixel = function()
+            { return (this.lat_quant/this.scale)/this.tileheight; }
+
+    this.xToLon = function(x)
+            { return this.lon + (x-this.thewidth/2)*this.lonPerPixel(); } 
+
+    this.yToLat = function(y)
+            { return normallat(this.lat - (y-this.theheight/2)
+                                *this.latPerPixel()); } 
+
+       this.lonToX = function (lon)
+                       { return ((lon-this.lon)/this.lonPerPixel()) + this.thewidth/2;}
+
+       this.latToY = function(lat)
+                       { return ((this.lat-mercatorlat(lat))/this.latPerPixel()) + 
+                                                       this.theheight/2; }
+
+
+    //
+    // it is possible that this collection is already in use - clean it
+    //
+    this.clean = function() 
+    { 
+               /*
+        while( this.parent.hasChildNodes() ) 
+            this.parent.removeChild( this.parent.firstChild );
+                       */
+
+               for(var ct=0; ct<this.parent.childNodes.length; ct++)
+               {
+                       if(this.parent.childNodes[ct].id != "controls")
+                               this.parent.removeChild(this.parent.childNodes[ct]);
+               }
+
+        //
+        // build inner tile container for theoretical speed improvement?
+        // center in parent for simplicity of math
+        // size of inner container is irrelevant since overflow is enabled
+        //
+
+        if( this.dragcontainer ) 
+        {
+            this.tiles = document.createElement('div');
+            this.tiles.style.position = 'absolute';
+            this.tiles.style.left = this.displaywidth/2 + 'px';
+            this.tiles.style.top = this.displayheight/2 + 'px';
+            this.tiles.style.width = '16px';
+            this.tiles.style.height = '16px';
+            if( this.debug ) 
+            {
+                this.tiles.style.border = 'dashed green 1px';
+            }
+            this.tiles.tile_engine = this;
+            this.parent.appendChild(this.tiles);
+
+        } 
+        else 
+        {
+            this.tiles = this.parent;
+        }
+    }
+
+    /// focus over specified lon/lat and zoom
+    /// user should call this.drag(0,0) after this to force an initial refresh
+    ///
+
+    this.performzoom = function(lon,lat,z) 
+    {
+        // setup for zoom
+        // this engine operates at * scale to try avoid tile errors thrashing 
+        // server cache
+        
+        this.scale = 1000000;
+        this.lon_min_clamp = -180 * this.scale;
+        this.lon_max_clamp = 180 * this.scale;
+        this.lat_min_clamp = -180 * this.scale; //t
+        this.lat_max_clamp = 180 * this.scale; //t
+        this.lon_start_tile = 180 * this.scale;
+        this.lat_start_tile = 90 * this.scale; //t
+        this.zoom_power = 2;
+        this.lon_quant = this.lon_start_tile;
+        this.lat_quant = this.lat_start_tile;
+        this.lon = lon;
+        this.lat = lat;
+
+        // operational lat - = lat due to quirks in our engine and quirks in o
+        // lon/lat design
+        lat = -lat;
+
+        // divide tile size until reach requested zoom
+        // trying to guarantee consistency so as to not thrash the server side tile cache
+        while(z > 0) 
+        {
+            this.lon_quant = this.lon_quant / this.zoom_power;
+            this.lat_quant = this.lat_quant / this.zoom_power;
+            z--;
+        }
+        this.lon_quant = Math.round( this.lon_quant );
+        this.lat_quant = Math.round( this.lat_quant );
+    
+        // get user requested exact lon/lat
+        this.lon_scaled = Math.round( lon * this.scale );
+        this.lat_scaled = Math.round( lat * this.scale );
+    
+
+
+        // convert requested exact lon/lat to quantized lon lat (rounding down 
+        // or up as best suits)
+        this.lon_round = Math.round( this.lon_scaled / this.lon_quant ) * 
+                this.lon_quant;
+        this.lat_round = Math.round( this.lat_scaled / this.lat_quant ) * 
+                this.lat_quant;
+    
+        //alert('lon_round=' + this.lon_round+ ' lat_round='+this.lat_round);
+
+        // calculate world extents [ this is the span of all tiles in lon/lat ]
+        this.lon_min = this.lon_round - this.lon_quant;
+        this.lon_max = this.lon_round + this.lon_quant;
+        this.lat_min = this.lat_round - this.lat_quant;
+        this.lat_max = this.lat_round + this.lat_quant;
+    
+        // set tiled region details [ this is the span of all tiles in pixels ]
+        this.centerx = 0;
+        this.centery = 0;
+        this.tilewidth = 256;
+        this.tileheight = 128;
+        this.left = -this.tilewidth;
+        this.right = this.tilewidth;
+        this.top = -this.tileheight;
+        this.bot = this.tileheight;
+
+
+        // adjust the current center position slightly to reflect exact lat/lon
+        // not rounded
+        this.centerx -= (this.lon_scaled-this.lon_round)/
+            (this.lon_max-this.lon_min)*(this.right-this.left);
+        this.centery -= (this.lat_scaled-this.lat_round)/
+            (this.lat_max-this.lat_min)*(this.bot-this.top);
+    }
+
+       this.update_perma_link = function() {
+               // because we're using mercator
+               updatelinks(this.lon,normallat(this.lat),this.zoom);
+       }
+
+    ///
+    /// draw the spanning lon/lat range
+    /// drag is simply the mouse delta in pixels
+    ///
+
+    this.drag = function(dragx,dragy) 
+    {
+               var fred=true;
+
+        // move the drag offset
+        this.centerx += dragx;
+        this.centery += dragy;
+
+        // update where we think the user is actually focused
+        this.lon = ( this.lon_round - ( this.lon_max - this.lon_min ) / 
+            ( this.right - this.left ) * this.centerx ) / this.scale;
+        this.lat = - ( this.lat_round - ( this.lat_max - this.lat_min ) / 
+            ( this.bot - this.top ) * this.centery ) / this.scale;
+
+               this.update_perma_link();
+
+        // show it
+        var helper = this.navhelp; 
+
+         // extend exposed sections
+        var dirty = false;
+        while( this.left + this.centerx > -this.displaywidth/2 && 
+                this.lon_min > this.lon_min_clamp ) 
+        {
+            this.left -= this.tilewidth;
+            this.lon_min -= this.lon_quant;
+            dirty = true;
+        }
+        while( this.right + this.centerx < this.displaywidth/2 && 
+                this.lon_max < this.lon_max_clamp ) 
+        {
+            this.right += this.tilewidth;
+            this.lon_max += this.lon_quant;
+            dirty = true;
+        }
+        while( this.top + this.centery > -this.displayheight/2 && 
+        this.lat_min > this.lat_min_clamp ) 
+        {
+            this.top -= this.tileheight;
+            this.lat_min -= this.lat_quant;
+            dirty = true;
+        }
+
+        while( this.bot + this.centery < this.displayheight/2 && 
+        this.lat_max < this.lat_max_clamp ) 
+        {
+            this.bot += this.tileheight;
+            this.lat_max += this.lat_quant;
+            dirty = true;
+        }
+
+
+        // prepare to walk the container and assure that all nodes are correct
+        var containerx;
+        var containery;
+
+        // in drag container mode we do not have to move the children all the 
+        // time
+        if( this.dragcontainer ) 
+        {
+            this.tiles.style.left = this.displaywidth / 2 + this.centerx + 'px';
+            this.tiles.style.top = this.displayheight / 2 + this.centery + 'px';
+            if( !dirty && this.tiles.hasChildNodes() ) 
+            {
+                return;
+            }
+            containerx = this.left;
+            containery = this.top;
+        } 
+        else 
+        {
+            containerx = this.left + this.centerx;
+            containery = this.top + this.centery;
+        }
+
+        // walk all tiles and repair as needed
+        // xxx one bug is that it walks the _entire_ width and height... 
+        // not just visible.
+        // xxx this makes cleanup harder and perhaps a bitmap is better
+
+        var removehidden = 1;
+        var removecolumn = 0;
+        var removerow = 0;
+        var containeryreset = containery;
+
+        for( var x = this.lon_min; x < this.lon_max ; x+= this.lon_quant ) 
+        {
+            // will this row be visible in the next round?
+            if( removehidden ) 
+            {
+                var rx = containerx + this.centerx;
+                if( rx > this.displaywidth / 2 ) 
+                {
+                    removerow = 1;
+                    // ideally i would truncate max width here
+                } 
+                else if( rx + this.tilewidth < - this.displaywidth / 2 ) 
+                {
+                    removerow = 1;
+                } 
+                else 
+                {
+                    removerow = 0;
+                }
+            }
+
+            for( var y = this.lat_min; y < this.lat_max ; y+= this.lat_quant ) 
+            {
+                // is this column visible?
+                if( removehidden ) 
+                {
+                    var ry = containery + this.centery;
+                    if( ry > this.displayheight / 2 ) 
+                    {
+                        removecolumn = 1;
+                    } 
+                    else if( ry + this.tileheight < - this.displayheight/2) 
+                    {
+                        removecolumn = 1;
+                    } 
+                    else 
+                    {
+                        removecolumn = 0;
+                    }
+                }
+
+                // convert to WMS compliant coordinate system
+                var lt = x / this.scale;
+                var rt = lt + this.lon_quant / this.scale;
+                var tp = y / this.scale;
+                var bt = tp + this.lat_quant / this.scale;
+                var temp = bt;
+                var bt = -tp;
+                var tp = -temp;
+
+                // modify for mercator-projected tiles: 
+                tp = 180/PI * (2 * Math.atan(Math.exp(tp * PI / 180)) - PI / 2);
+                bt = 180/PI * (2 * Math.atan(Math.exp(bt * PI / 180)) - PI / 2);
+                
+                // make a key
+                var key = this.url + "?WIDTH="+(this.tilewidth)+"&HEIGHT="+
+                    (this.tileheight)+"&BBOX="+lt+","+tp+","+rt+","+bt;
+
+                // see if our tile is already present
+                var node = document.getElementById(key);
+
+                // create if not present
+                if(!node) 
+                {
+                    if( this.debug > 0) 
+                    {
+                        node = document.createElement('div');
+                    } 
+                    else 
+                    {
+                        node = document.createElement('img');
+                    }
+                    node.id = key;
+                    node.className = 'tile';
+                    node.style.position = 'absolute';
+                    node.style.width = this.tilewidth + 'px';
+                    node.style.height = this.tileheight + 'px';
+                    node.style.left = containerx + 'px';
+                    node.style.top = containery + 'px';
+                    node.style.zIndex = 10; // to appear under the rss elements
+                    node.tile_engine = this;
+                    if( this.debug > 0) 
+                    {
+                        node.style.border = "1px solid yellow";
+                        node.innerHTML = key;
+                        if( this.debug > 1 ) 
+                        {
+                            var img = document.createElement('img');
+                            img.src = key;
+                            node.appendChild(img);
+                        }
+                    }
+
+                    var goURL = key + "&zoom=" + this.zoom; 
+                                                       
+                                   for(var k in this.urlAttr) 
+                                       {
+                                               goURL += "&"+k+"="+this.urlAttr[k];
+                                       }
+                               
+                                       node.src = goURL;
+
+                    node.alt = "loading tile..";
+                    node.style.color = "#ffffff";
+                    this.tiles.appendChild(node);
+                }
+                // adjust if using active style
+                else if( !this.dragcontainer ) {
+                    node.style.left = containerx + 'px';
+                    node.style.top = containery + 'px';
+                }
+
+                containery += this.tileheight;
+            }
+            containery = containeryreset;
+            containerx += this.tilewidth;
+        }
+    }
+
+    this.zoomTo = function(zoom) 
+    {
+
+        this.zoom  = zoom;
+    
+        if (this.zoom < this.minzoom) { this.zoom = this.minzoom; }
+        if (this.zoom > this.maxzoom) { this.zoom = this.maxzoom; }
+
+
+
+
+        ///
+        /// immediately draw and or fit to feed
+        ///
+        this.performzoom(this.lon,this.lat,zoom);
+        this.drag(0,0);
+
+        ///
+    } // CLOSE ZOOM FUNCTION
+
+    this.setLatLon = function(lat,lon)
+    { 
+        this.lon=lon; 
+        this.lat=mercatorlat(lat); 
+        this.clean(); 
+        this.performzoom(lon,mercatorlat(lat),this.zoom);
+        this.drag(0,0); 
+    }
+
+       this.forceRefresh = function()
+       {
+               this.clean();
+        this.performzoom(this.lon,this.lat,this.zoom);
+        this.drag(0,0); 
+       }
+
+    ///
+    /// zoom a tile group
+    ///
+    this.tile_engine_zoomout = function() 
+    {
+        this.clean();
+        this.zoomTo(this.zoom-1);
+
+        return false; // or safari falls over
+    }
+
+    ///
+    /// zoom a tile group
+    ///
+    this.tile_engine_zoomin = function() 
+    {
+        
+        this.clean();
+        this.zoomTo(this.zoom+1);
+  
+        return false; // or safari falls over
+    }
+
+    this.setURL=function(url) { this.url=url; }
+
+
+
+    ///
+    /// intercept context events to minimize out-of-browser interruptions
+    ///
+    
+    this.event_context = function(e) 
+    {
+        return false;
+    }
+
+    ///
+    /// keys
+    ///
+
+    this.event_key = function(e) 
+    {
+        var key = 0;        
+
+        var hostengine = defaultEngine;
+
+        if( window && window.event && window.event.srcElement ) {
+            hostengine = window.event.srcElement.tile_engine;
+        } else if( e.target ) {
+            hostengine = e.target.tile_engine;
+        } else if( e.srcElement ) {
+            hostengine = e.srcElement.tile_engine;
+        }
+
+        if( hostengine == null ) {
+            hostengine = defaultEngine;
+            if( hostengine == null ) {
+                return;
+            }
+        }
+
+
+        if( e == null && document.all ) {
+            e = window.event;
+        }
+
+        if( e ) {
+            if( e.keyCode ) {
+                key = e.keyCode;
+            }
+            else if( e.which ) {
+                key = e.which;
+            }
+
+            switch(key) {
+            case 97: // a = left
+                hostengine.drag(16,0);
+                break;
+            case 100: // d = right
+                hostengine.drag(-16,0);
+                break;
+            case 119: // w = up
+                hostengine.drag(0,16);
+                break;
+            case 120: // x = dn
+                hostengine.drag(0,-16);
+                break;
+            case 115: // s = center
+                new tile_engine_new(hostengine.parentname,
+                            "FULL",
+                            hostengine.feedurl, // xxx hrm, cache this?
+                            hostengine.url,
+                            hostengine.lon,
+                            hostengine.lat,
+                            hostengine.zoom,
+                            0,0
+                            );
+                break;
+            case 122: // z = zoom
+                new tile_engine_new(hostengine.parentname,
+                            "FULL",
+                            hostengine.feedurl, // xxx hrm, cache this?
+                            hostengine.url,
+                            hostengine.lon,
+                            hostengine.lat,
+                            hostengine.zoom + 1,
+                            0,0
+                            );
+                break;
+            case  99: // c = unzoom
+                new tile_engine_new(hostengine.parentname,
+                            "FULL",
+                            hostengine.feedurl, // xxx hrm, cache this?
+                            hostengine.url,
+                            hostengine.lon,
+                            hostengine.lat,
+                            hostengine.zoom - 1,
+                            0,0
+                            );
+                break;
+            }
+        }    
+    }
+
+    ///
+    /// catch mouse move events
+    /// this routine _must_ return false or else the operating system outside-of-browser-scope drag and drop handler will interfere
+    ///
+
+    this.event_mouse_move = function(e) {
+
+        var hostengine = null;
+        if( window && window.event && window.event.srcElement ) {
+            hostengine = window.event.srcElement.tile_engine;
+        } else if( e.target ) {
+            hostengine = e.target.tile_engine;
+        } else if( e.srcElement ) {
+            hostengine = e.srcElement.tile_engine;
+        }
+
+
+        if( hostengine && hostengine.drag ) {
+            if( hostengine.mousedown ) {
+                if( netscape ) {
+                    hostengine.mousex = parseInt(e.pageX) + 0.0;
+                    hostengine.mousey = parseInt(e.pageY) + 0.0;
+                } else {
+                    hostengine.mousex = parseInt(window.event.clientX) + 0.0;
+                    hostengine.mousey = parseInt(window.event.clientY) + 0.0;
+                }
+                hostengine.drag(hostengine.mousex-hostengine.lastmousex,hostengine.mousey-hostengine.lastmousey);
+            }
+            hostengine.lastmousex = hostengine.mousex;
+            hostengine.lastmousey = hostengine.mousey;
+        }
+
+        // must return false to prevent operating system drag and drop from handling events
+        return false;
+    }
+
+    ///
+    /// catch mouse down
+    ///
+
+    this.event_mouse_down = function(e) {
+
+        var hostengine = null;
+        if( window && window.event && window.event.srcElement ) {
+            hostengine = window.event.srcElement.tile_engine;
+        } else if( e.target ) {
+            hostengine = e.target.tile_engine;
+        } else if( e.srcElement ) {
+            hostengine = e.srcElement.tile_engine;
+        }
+
+
+        if( hostengine ) {
+            if( netscape ) {
+                hostengine.mousex = parseInt(e.pageX) + 0.0;
+                hostengine.mousey = parseInt(e.pageY) + 0.0;
+            } else {
+                hostengine.mousex = parseInt(window.event.clientX) + 0.0;
+                hostengine.mousey = parseInt(window.event.clientY) + 0.0;
+            }
+            hostengine.lastmousex = hostengine.mousex;
+            hostengine.lastmousey = hostengine.mousey;
+            hostengine.mousedown = 1;
+        }
+
+        // must return false to prevent operating system drag and drop from handling events
+        return false;
+    }
+
+    ///
+    /// catch double click (use to center map)
+    ///
+
+    this.event_double_click = function(e) {
+
+        var hostengine = null;
+        if( window && window.event && window.event.srcElement ) {
+            hostengine = window.event.srcElement.tile_engine;
+        } else if( e.target ) {
+            hostengine = e.target.tile_engine;
+        } else if( e.srcElement ) {
+            hostengine = e.srcElement.tile_engine;
+        }
+
+
+        if( hostengine ) {
+            if( netscape ) {
+                hostengine.mousex = parseInt(e.pageX) + 0.0;
+                hostengine.mousey = parseInt(e.pageY) + 0.0;
+            } else {
+                hostengine.mousex = parseInt(window.event.clientX) + 0.0;
+                hostengine.mousey = parseInt(window.event.clientY) + 0.0;
+            }
+            var dx = hostengine.mousex-(hostengine.displaywidth/2)-hostengine.parent_x;
+            var dy = hostengine.mousey-(hostengine.displayheight/2)-hostengine.parent_y;
+            hostengine.drag(-dx,-dy); // TODO smooth
+        }
+
+        // must return false to prevent operating system drag and drop from handling events
+        return false;
+
+    }
+
+    ///
+    /// catch mouse up
+    ///
+
+    this.event_mouse_up = function(e) {
+
+        var hostengine = null;
+        if( window && window.event && window.event.srcElement ) {
+            hostengine = window.event.srcElement.tile_engine;
+        } else if( e.target ) {
+            hostengine = e.target.tile_engine;
+        } else if( e.srcElement ) {
+            hostengine = e.srcElement.tile_engine;
+        }
+        
+
+        if( hostengine ) {
+            if( netscape ) {
+                hostengine.mousex = parseInt(e.pageX) + 0.0;
+                hostengine.mousey = parseInt(e.pageY) + 0.0;
+            } else {
+                hostengine.mousex = parseInt(window.event.clientX) + 0.0;
+                hostengine.mousey = parseInt(window.event.clientY) + 0.0;
+            }
+            hostengine.mousedown = 0;
+        }
+
+        // must return false to prevent operating system drag and drop from handling events
+        return false;
+    }
+
+    ///
+    /// catch mouse out
+    ///
+
+    this.event_mouse_out = function(e) {
+
+        var hostengine = null;
+        if( window && window.event && window.event.srcElement ) {
+            hostengine = window.event.srcElement.tile_engine;
+        } else if( e.target ) {
+            hostengine = e.target.tile_engine;
+        } else if( e.srcElement ) {
+            hostengine = e.srcElement.tile_engine;
+        }
+
+
+        if( hostengine ) {
+            if( netscape ) {
+                hostengine.mousex = parseInt(e.pageX) + 0.0;
+                hostengine.mousey = parseInt(e.pageY) + 0.0;
+            } else {
+                hostengine.mousex = parseInt(window.event.clientX) + 0.0;
+                hostengine.mousey = parseInt(window.event.clientY) + 0.0;
+            }
+            hostengine.mousedown = 0;
+        }
+
+        // must return false to prevent operating system drag and drop from handling events
+        return false;
+    }
+
+
+    ///
+    /// register new handlers to catch desired events
+    ///
+
+    // NW removed parameter - always use parent
+    this.event_catch = function() {
+
+       this.parent.style.cursor = 'move';
+
+        if( netscape ) {
+            window.captureEvents(Event.MOUSEMOVE);
+            window.captureEvents(Event.KEYPRESS);
+        }
+
+        this.parent.onmousemove = this.event_mouse_move;
+        this.parent.onmousedown = this.event_mouse_down;
+        this.parent.onmouseup = this.event_mouse_up;
+        this.parent.onkeypress = this.event_key;
+        window.ondblclick = this.event_double_click;
+
+        if( window ) {
+            window.onmousemove = this.event_mouse_move;
+            window.onmouseup = this.event_mouse_up;
+            window.ondblclick = this.event_double_click;
+        }
+
+    }
+
+       this.setURLAttribute = function(k,v)
+       {
+               this.urlAttr[k] = v; 
+       }
+
+       this.getURLAttribute = function(k)
+       {
+               return this.urlAttr[k];
+       }
+
+       this.getDownloadedTileBounds = function()
+       {
+               var bounds = new Array();
+               bounds.w=this.lon_min; 
+               bounds.s=normallat(this.lat_min);
+               bounds.e=this.lon_max;
+               bounds.n=normallat(this.lat_max);
+               return bounds;
+       }
+
+       this.getVisibleBounds = function()
+       {
+               var bounds = new Array();
+               bounds.w = this.xToLon(0);
+               bounds.s = this.yToLat(this.theheight);
+               bounds.e = this.xToLon(this.thewidth);
+               bounds.n = this.yToLat(0);
+               return bounds;
+       }
+       
+       // navout and navin stuff - START
+       // draw navigation buttons into the parent div
+
+    // ENTRY CODE BEGINS HERE....
+
+
+    // get parent div or fail
+    this.parent = document.getElementById(parentname);
+    if( this.parent == null ) {
+        alert('The tile map engine cannot find a parent container named ['
+                +parentname+']');
+        return;
+    }
+
+    //
+    // store for later
+    //
+
+    this.parentname = parentname;
+    this.hints = hints;
+    this.feedurl = feedurl;
+    this.url = url;
+    this.lon = lon;
+    this.lat = mercatorlat(lat);
+    this.thewidth = w;
+    this.theheight = h;
+    this.dragcontainer = 1;
+    this.debug = 0;
+
+    // for firefox keyboard
+    defaultEngine = this;
+    document.engine = this;
+
+
+    //
+    // decide on display width and height
+    //
+    if( !w || !h ) 
+       {
+        w = parseInt(this.parent.style.width);
+        h = parseInt(this.parent.style.height);
+        if(!w || !h) 
+               {
+            w = 512;
+            h = 256;
+            this.parent.style.width = w + 'px';
+            this.parent.style.height = h + 'px';
+        }
+    } 
+       else 
+       {
+        this.parent.style.width = parseInt(w) + 'px';
+        this.parent.style.height = parseInt(h) + 'px';
+    }
+    this.displaywidth = w;
+    this.displayheight = h;
+
+    this.minzoom = 0;
+    this.maxzoom = 20;
+
+    //
+    // enforce parent div style?
+    // position absolute is really only required for firefox
+    // http://www.quirksmode.org/js/findpos.html
+    //
+
+    this.parent_x = getCSSPositionX(this.parent);
+    this.parent_y = getCSSPositionY(this.parent);
+
+    this.parent.style.position = 'relative';
+    this.parent.style.overflow = 'hidden';
+    this.parent.style.backgroundColor = '#000036';
+
+
+       // attach event capture parent div
+       this.event_catch();
+
+    this.clean();
+       //this.makeZoom();
+
+    this.zoomTo(zoom);
+}
+
+
+function normallat(mercatorlat)
+{
+    var tp = 180/PI*(2 * Math.atan(Math.exp(mercatorlat * PI / 180)) - PI / 2);
+    return tp;
+}
+
+function mercatorlat(normallat)
+{
+  var lpi =  3.14159265358979323846;
+  return  Math.log( Math.tan( (lpi / 4.0) + (normallat / 180.0 * lpi / 2.0))) * 
+                      180.0 / lpi ;
+}