source: Dev/trunk/src/client/dojox/drawing/annotations/Angle.js

define(["dojo", "../util/oo", "../util/positioning"], 
function(dojo, oo, positioning){

//dojox.drawing.annotations.Angle = 
return oo.declare(
        function(/*Object*/ options){
                // options: Object
                //              One key value: the stencil that called this.

                this.stencil = options.stencil;
                this.util = options.stencil.util;
                this.mouse = options.stencil.mouse;

                this.stencil.connectMult([
                        ["onDrag", this, "showAngle"],
                        ["onUp", this, "hideAngle"],
                        ["onTransformBegin", this, "showAngle"],
                        ["onTransform", this, "showAngle"],
                        ["onTransformEnd", this, "hideAngle"]
                ]);
        },
        {
                // summary:
                //              When initiated, an HTML box will hover near the Stencil,
                //              displaying it's angle while drawn or modified. Currently
                //              only works with Vector, Line, Arrow, and Axes.
                // description:
                //              Annotation is positioned with dojox.drawing.util.positioning.angle
                //              That method should be overwritten for custom placement.
                //              Called internally.

                type:"dojox.drawing.tools.custom",
                angle:0,

                showAngle: function(){
                        // summary:
                        //              Called to display angle

                        if(!this.stencil.selected && this.stencil.created){ return; }
                        if(this.stencil.getRadius() < this.stencil.minimumSize){
                                this.hideAngle();
                                return;
                        }
                        var node = this.getAngleNode();
                        var d = this.stencil.pointsToData();
                        var pt = positioning.angle({x:d.x1,y:d.y1},{x:d.x2,y:d.y2});
                        var sc = this.mouse.scrollOffset();
                        var mx = this.stencil.getTransform();
                        var dx = mx.dx / this.mouse.zoom;
                        var dy = mx.dy / this.mouse.zoom;
                        pt.x /= this.mouse.zoom;
                        pt.y /= this.mouse.zoom;

                        // adding _offX & _offY since this is HTML
                        // and we are from the page corner, not
                        // the canvas corner
                        var x = this.stencil._offX + pt.x - sc.left + dx;
                        var y = this.stencil._offY + pt.y - sc.top + dy;
                        dojo.style(node, {
                                left:   x + "px",
                                top:    y + "px",
                                align:pt.align
                        });

                        var angle=this.stencil.getAngle();
                        if(this.stencil.style.zAxis && this.stencil.shortType=="vector"){
                          node.innerHTML = this.stencil.data.cosphi > 0 ? "out of" : "into";
                        }else if(this.stencil.shortType=="line"){
                          node.innerHTML = this.stencil.style.zAxis?"out of":Math.ceil(angle%180);
                        }else{
                          node.innerHTML = Math.ceil(angle);
                        }
                },

                getAngleNode: function(){
                        // summary:
                        //              Gets or creates HTMLNode used for display
                        if(!this._angleNode){
                                this._angleNode = dojo.create("span", null, dojo.body());
                                dojo.addClass(this._angleNode, "textAnnotation");
                                dojo.style(this._angleNode, "opacity", 1);
                        }
                        return this._angleNode; //HTMLNode
                },

                hideAngle: function(){
                        // summary:
                        //              Turns display off.

                        if(this._angleNode && dojo.style(this._angleNode, "opacity")>0.9){

                                dojo.fadeOut({node:this._angleNode,
                                        duration:500,
                                        onEnd: function(node){
                                                dojo.destroy(node);
                                        }
                                }).play();
                                this._angleNode = null;
                        }

                }
        }
);
});