source: Dev/branches/rest-dojo-ui/client/dojox/drawing/annotations/Arrow.js @ 256

dojo.provide("dojox.drawing.annotations.Arrow");
dojo.require("dojox.drawing.stencil.Path");

dojox.drawing.annotations.Arrow = dojox.drawing.util.oo.declare(
        // summary:
        //      An annotation called internally to put an arrowhead
        //      on ether end of a Line. Initiated in Arrow (and Vector)
        //      with the optional params: arrowStart and arrowEnd. Both
        //      default true for Axes.
        //
        dojox.drawing.stencil.Path,
        function(/* dojox.__stencilArgs */options){
                // arguments: See stencil._Base
                this.stencil.connectMult([
                        [this.stencil, "select", this, "select"],
                        [this.stencil, "deselect", this, "deselect"],
                        [this.stencil, "render", this, "render"],
                        [this.stencil, "onDelete", this, "destroy"]
                ]);
                
                this.connect("onBeforeRender", this, function(){
                        var o = this.stencil.points[this.idx1];
                        var c = this.stencil.points[this.idx2];
                        if(this.stencil.getRadius() >= this.minimumSize){
                                this.points = this.arrowHead(c.x, c.y, o.x, o.y, this.style);
                        }else{
                                this.points = [];
                        }
                });
                
        },
        {
                idx1:0,
                idx2:1,
                
                subShape:true,
                minimumSize:30,
                //annotation:true, NOT!
                
                arrowHead: function(x1, y1, x2, y2, style){
                        // summary:
                        //      Creates data used to draw arrow head.
                        //
                        var obj = {
                                start:{
                                        x:x1,
                                        y:y1
                                },
                                x:x2,
                                y:y2
                        }
                        var angle = this.util.angle(obj);
                        
                        var lineLength = this.util.length(obj);
                        var al = style.arrows.length;
                        var aw = style.arrows.width/2;
                        if(lineLength<al){
                                al = lineLength/2;
                        }
                        var p1 = this.util.pointOnCircle(x2, y2, -al, angle-aw);
                        var p2 = this.util.pointOnCircle(x2, y2, -al, angle+aw);
                        
                        return [
                                {x:x2, y:y2},
                                p1,
                                p2
                        ];
                }
                
        }
);