dojox.drawing.Drawing - custom tool to create rectangle with rounded corners

Question

I'm working with dojox.drawing.Drawing to create a simple diagramming tool. I have created a custom tool to draw rounded rectangle by extending dojox.drawing.tools.Rect as shown below -

dojo.provide("dojox.drawing.tools.custom.RoundedRect");
dojo.require("dojox.drawing.tools.Rect");

dojox.drawing.tools.custom.RoundedRect = dojox.drawing.util.oo.declare(

        dojox.drawing.tools.Rect,
        function(options){
        },
        {
          customType:"roundedrect"
        }    
);

dojox.drawing.tools.custom.RoundedRect.setup = {
    name:"dojox.drawing.tools.custom.RoundedRect",
    tooltip:"Rounded Rect",
    iconClass:"iconRounded"
};
dojox.drawing.register(dojox.drawing.tools.custom.RoundedRect.setup, "tool");

I was able to add my tool to the toolbar and use it to draw a rectagle on canvas. Now, I would like to customize the rectangle created by my custom tool to have rounded corners, but I'm not able to figure out how. I have checked the source of dojox.drawing.tools.Rect class as well as it's parent dojox.drawing.stencil.Rect class and I can see the actual rectangle being created in dojox.drawing.stencil.Rect as follows -

_create: function(/*String*/shp, /*StencilData*/d, /*Object*/sty){
        // summary:
        //              Creates a dojox.gfx.shape based on passed arguments.
        //              Can be called many times by implementation to create
        //              multiple shapes in one stencil.
        //
        //console.log("render rect", d)
        //console.log("rect sty:", sty)
        this.remove(this[shp]);
        this[shp] = this.container.createRect(d)
                .setStroke(sty)
                .setFill(sty.fill);

        this._setNodeAtts(this[shp]);
}

In dojox.gfx, rounded corners can be added to a a rectangle by setting r property. With this context, could anybody please provide answers to my following questions?

1. What's the mechanism in dojox.drawing to customize the appearance of rectangle to have rounded corners?
2. In the code snippet above, StencilData is passed to createRect call. What's the mechanism to customize this data? Can the r property of a rectangle that governs rounded corners be set in this data?

Answer 1

Adding rounded rectangles programmatically is easy. In the tests folder you'll find test_shadows.html which has a line that adds a rectangle with rounded corners:

myDrawing.addStencil("rect", {data:{x:50, y:175, width:100, height:50, r:10}});

You create a data object with x,y,width,height, and a value for r (otherwise it defaults to 0).

If you wanted to do it by extending rect, the easiest way to do it would just be to set the value in the constructor function (data.r=10, for example), or you could create a pointsToData function to override Rect's version. Either you would have set the value for this.data.r, or the default:

pointsToData: function(/*Array*/p){
        // summary:
        //      Converts points to data
        p = p || this.points;
        var s = p[0];
        var e = p[2];
        this.data = {
            x: s.x,
            y: s.y,
            width: e.x-s.x,
            height: e.y-s.y,
            r:this.data.r || 10
        };
        return this.data;

    },

In that example I give r the value 10 as the default, instead of 0 as it was before. This works because every time stencil goes to draw your rect, it converts canvas x,y points (all stencils remember their points) to data (which gfx uses to draw). In other words this function will always be called before rect renders.