source: Dev/trunk/src/client/dojox/treemap/ScaledLabel.js

define(["dojo/_base/declare", "dojo/dom-geometry", "dojo/dom-construct", "dojo/dom-style"],
        function(declare, domGeom, domConstruct, domStyle) {

        return declare("dojox.treemap.ScaledLabel", null, {
                // summary:
                //              Specializes TreeMap to display scaled leaf labels instead of constant size labels.

                onRendererUpdated: function(evt){
                        if(evt.kind == "leaf"){
                                var renderer = evt.renderer;
                                // start back with default size
                                var oldSize = domStyle.get(renderer, "fontSize");
                                domStyle.set(renderer.firstChild, "fontSize", oldSize);
                                oldSize = parseInt(oldSize);
                                var hRatio = 0.75 * domGeom.getContentBox(renderer).w / domGeom.getMarginBox(renderer.firstChild).w;
                                var vRatio = domGeom.getContentBox(renderer).h  / domGeom.getMarginBox(renderer.firstChild).h;
                                var hDiff = domGeom.getContentBox(renderer).w - domGeom.getMarginBox(renderer.firstChild).w;
                                var vDiff = domGeom.getContentBox(renderer).h - domGeom.getMarginBox(renderer.firstChild).h;
                                var newSize = Math.floor(oldSize * Math.min(hRatio, vRatio));
                                while(vDiff > 0 && hDiff > 0){
                                        domStyle.set(renderer.firstChild, "fontSize", newSize + "px");
                                        hDiff = domGeom.getContentBox(renderer).w - domGeom.getMarginBox(renderer.firstChild).w;
                                        vDiff = domGeom.getContentBox(renderer).h - domGeom.getMarginBox(renderer.firstChild).h;
                                        oldSize = newSize;
                                        newSize += 1;
                                }
                                if(vDiff < 0 || hDiff < 0){
                                        // back track
                                        domStyle.set(renderer.firstChild, "fontSize", oldSize + "px");
                                }
                        }
                },

                createRenderer: function(item, level, kind){
                        var renderer = this.inherited(arguments);
                        if(kind == "leaf"){
                                var p = domConstruct.create("div");
                                domStyle.set(p, {
                                        "position": "absolute",
                                        "width": "auto"
                                });
                                domConstruct.place(p, renderer);
                        }
                        return renderer;
                },
                
                styleRenderer: function(renderer, item, level, kind){
                        if (kind != "leaf"){
                                this.inherited(arguments);
                        }else{
                                domStyle.set(renderer, "background", this.getColorForItem(item).toHex());
                                renderer.firstChild.innerHTML = this.getLabelForItem(item);
                        }
                }
        });
});