source: Dev/trunk/src/client/dojox/gfx/renderer.js

define(["./_base","dojo/_base/lang", "dojo/_base/sniff", "dojo/_base/window", "dojo/_base/config"],
  function(g, lang, has, win, config){
  //>> noBuildResolver
        var currentRenderer = null;

        has.add("vml", function(global, document, element){
                element.innerHTML = "<v:shape adj=\"1\"/>";
                var supported = ("adj" in element.firstChild);
                element.innerHTML = "";
                return supported;
        });

        return {
                // summary:
                //              This module is an AMD loader plugin that loads the appropriate graphics renderer
                //              implementation based on detected environment and current configuration settings.
                
                load: function(id, require, load){
                        // tags:
                        //      private
                        if(currentRenderer && id != "force"){
                                load(currentRenderer);
                                return;
                        }
                        var renderer = config.forceGfxRenderer,
                                renderers = !renderer && (lang.isString(config.gfxRenderer) ?
                                        config.gfxRenderer : "svg,vml,canvas,silverlight").split(","),
                                silverlightObject, silverlightFlag;

                        while(!renderer && renderers.length){
                                switch(renderers.shift()){
                                        case "svg":
                                                // the next test is from https://github.com/phiggins42/has.js
                                                if("SVGAngle" in win.global){
                                                        renderer = "svg";
                                                }
                                                break;
                                        case "vml":
                                                if(has("vml")){
                                                        renderer = "vml";
                                                }
                                                break;
                                        case "silverlight":
                                                try{
                                                        if(has("ie")){
                                                                silverlightObject = new ActiveXObject("AgControl.AgControl");
                                                                if(silverlightObject && silverlightObject.IsVersionSupported("1.0")){
                                                                        silverlightFlag = true;
                                                                }
                                                        }else{
                                                                if(navigator.plugins["Silverlight Plug-In"]){
                                                                        silverlightFlag = true;
                                                                }
                                                        }
                                                }catch(e){
                                                        silverlightFlag = false;
                                                }finally{
                                                        silverlightObject = null;
                                                }
                                                if(silverlightFlag){
                                                        renderer = "silverlight";
                                                }
                                                break;
                                        case "canvas":
                                                if(win.global.CanvasRenderingContext2D){
                                                        renderer = "canvas";
                                                }
                                                break;
                                }
                        }

                        if (renderer === 'canvas' && config.canvasEvents !== false) {
                                renderer = "canvasWithEvents";
                        }

                        if(config.isDebug){
                                console.log("gfx renderer = " + renderer);
                        }

                        function loadRenderer(){
                                require(["dojox/gfx/" + renderer], function(module){
                                        g.renderer = renderer;
                                        // memorize the renderer module
                                        currentRenderer = module;
                                        // now load it
                                        load(module);
                                });
                        }
                        if(renderer == "svg" && typeof window.svgweb != "undefined"){
                                window.svgweb.addOnLoad(loadRenderer);
                        }else{
                                loadRenderer();
                        }
                }
        };
});