source: Dev/trunk/src/client/dojox/geo/openlayers/GfxLayer.js

define([
        "dojo/_base/declare",
        "dojo/_base/connect",
        "dojo/dom-style",
        "dojox/gfx",
        "dojox/gfx/matrix",
        "./Feature",
        "./Layer"
], function(declare, connect, style, gfx, matrix, Feature, Layer){

        return declare("dojox.geo.openlayers.GfxLayer", Layer, {
                // summary:
                //              A layer dedicated to render dojox.geo.openlayers.GeometryFeature
                // description:
                //              A layer class for rendering geometries as dojox.gfx.Shape objects.
                //              This layer class accepts Features which encapsulates graphic objects to be added to the map.
                //              All objects should be added to this group.
                // tags:
                //              private
                _viewport: null,

                constructor: function(name, options){
                        // summary:
                        //              Constructs a new GFX layer.
                        var s = gfx.createSurface(this.olLayer.div, 100, 100);
                        this._surface = s;
                        var vp;
                        if(options && options.viewport){
                                vp = options.viewport;
                        }else{
                                vp = s.createGroup();
                        }
                        this.setViewport(vp);
                        connect.connect(this.olLayer, "onMapResize", this, "onMapResize");
                        this.olLayer.getDataExtent = this.getDataExtent;
                },

                getViewport: function(){
                        // summary:
                        //              Gets the viewport
                        // tags:
                        //              internal
                        return this._viewport;
                },

                setViewport: function(g){
                        // summary:
                        //              Sets the viewport
                        // g: dojox.gfx.Group
                        // tags:
                        //              internal
                        if(this._viewport){
                                this._viewport.removeShape();
                        }
                        this._viewport = g;
                        this._surface.add(g);
                },

                onMapResize: function(){
                        // summary:
                        //              Called when map is resized.
                        // tags:
                        //              protected
                        this._surfaceSize();
                },

                setMap: function(map){
                        // summary:
                        //              Sets the map for this layer.
                        // tags:
                        //              protected
                        this.inherited(arguments);
                        this._surfaceSize();
                },

                getDataExtent: function(){
                        // summary:
                        //              Get data extent
                        // tags:
                        //              private
                        var ret = this._surface.getDimensions();
                        return ret;
                },

                getSurface: function(){
                        // summary:
                        //              Get the underlying dojox.gfx.Surface
                        // returns:
                        //              The dojox.gfx.Surface this layer uses to draw its GFX rendering.
                        return this._surface; // dojox.gfx.Surface
                },

                _surfaceSize: function(){
                        // summary:
                        //              Recomputes the surface size when being resized.
                        // tags:
                        //              private
                        var s = this.olLayer.map.getSize();
                        this._surface.setDimensions(s.w, s.h);
                },

                moveTo: function(event){
                        // summary:
                        //              Called when this layer is moved or zoomed.
                        // event:
                        //              The event
                        var s = style.get(this.olLayer.map.layerContainerDiv);
                        var left = parseInt(s.left);
                        var top = parseInt(s.top);

                        if(event.zoomChanged || left || top){
                                var d = this.olLayer.div;

                                style.set(d, {
                                        left: -left + "px",
                                        top: -top + "px"
                                });

                                if(this._features == null){
                                        return;
                                }
                                var vp = this.getViewport();

                                vp.setTransform(matrix.translate(left, top));

                                this.inherited(arguments);

                        }
                },

                added: function(){
                        // summary:
                        //              Called when added to a map.
                        this.inherited(arguments);
                        this._surfaceSize();
                }

        });
});