source: Dev/trunk/src/client/dojox/drawing/util/common.js

define(["dojo", "dojox/math/round"], function(dojo, round){

        var uidMap = {};
        var start = 0;
        //dojox.drawing.util.common     = 
        return {
                // summary:
                //              A collection of common methods used for DojoX Drawing.
                //              This singleton is accessible in most Drawing classes
                //              as this.util

                // NOTE:
                //              A lot of functions use a EventObject
                //              as an argument. An attempt was made to accept
                //              either that object or a list of numbers. That wasn't
                //              finished (it didn't work well in all cases) but is
                //              likely to happen in the future.
                //              In cases where you are not sending a Mouse object,
                //              form your argument like so:
                //              var obj = {
                //                      start:{
                //                                      x:Number,       // start x
                //                                      y:Number        // start y
                //                              },
                //                              x: Number,              // end x
                //                              y:Number                // end y
                //                      }


                radToDeg: function(/*Number*/n){
                        // summary:
                        //              Convert the passed number to degrees.
                        return (n*180)/Math.PI; //      Number
                },
                
                degToRad: function(/*Number*/n){
                        // summary:
                        //              Convert the passed number to radians.
                        return (n*Math.PI)/180; // Number
                },
                
                angle: function(/*EventObject*/obj, /*Float?*/snap){
                        // summary:
                        //              Return angle based on mouse object
                        // obj:
                        //              Manager.Mouse event.
                        // snap:
                        //              Returns nearest angle within snap limits

                        //obj = this.argsToObj.apply(this, arguments);
                        if(snap){
                                snap = snap/180;
                                var radians = this.radians(obj),
                                        seg = Math.PI * snap,
                                        rnd = round(radians/seg),
                                        new_radian = rnd*seg;
                                return round(this.radToDeg(new_radian)); // Whole Number
                        
                        }else{
                                return this.radToDeg(this.radians(obj)); // Float
                        }
                },
                
                oppAngle: function(/*Angle*/ang){
                        (ang+=180) > 360 ? ang = ang - 360 : ang;
                        return ang;
                },
                
                radians: function(/*EventObject*/o){
                        // summary:
                        //              Return the radians derived from the coordinates
                        //              in the Mouse object.

                        //var o = this.argsToObj.apply(this, arguments);
                        return Math.atan2(o.start.y-o.y,o.x-o.start.x);
                },
                
                length: function(/*EventObject*/o){
                        // summary:
                        //              Return the length derived from the coordinates
                        //              in the Mouse object.

                        return Math.sqrt(Math.pow(o.start.x-o.x, 2)+Math.pow(o.start.y-o.y, 2));
                },
                
                lineSub: function(/*Number*/x1, /*Number*/y1, /*Number*/x2, /*Number*/y2, /*Number*/amt){
                        // summary:
                        //              Subtract an amount from a line
                        // description:
                        //              x1,y1,x2,y2 represents the Line. 'amt' represents the amount
                        //              to subtract from it.

                        var len = this.distance(this.argsToObj.apply(this, arguments));
                        len = len < amt ? amt : len;
                        var pc = (len-amt)/len;
                        var x = x1 - (x1-x2) * pc;
                        var y = y1 - (y1-y2) * pc;
                        return {x:x, y:y}; // Object
                },
                
                argsToObj: function(){
                        // summary:
                        //              Attempts to determine in a Mouse Object
                        //              was passed or indiviual numbers. Returns
                        //              an object.

                        var a = arguments;
                        if(a.length < 4){ return a[0]; }
                        return {
                                start:{
                                        x:a[0],
                                        y:a[1]
                                },
                                x:a[2],
                                y:a[3]//,
                                //snap:a[4]
                        }; // Object
                },
                
                distance: function(/*EventObject or x1,y1,x2,y2*/){
                        // summary:
                        //              Return the length derived from the coordinates
                        //              in the Mouse object. Different from util.length
                        //              in that this always returns an absolute value.

                        var o = this.argsToObj.apply(this, arguments);
                        return Math.abs(Math.sqrt(Math.pow(o.start.x-o.x, 2)+Math.pow(o.start.y-o.y, 2))); // Number
                },
                
                slope:function(/*Object*/p1, /*Object*/p2){
                        // summary:
                        //              Given two poits of a line, returns the slope.
                        if(!(p1.x-p2.x)){ return 0; }
                        return ((p1.y-p2.y)/(p1.x-p2.x)); // Number
                },
                
                pointOnCircle: function(/*Number*/cx, /*Number*/cy, /*Number*/radius, /*Number*/angle){
                        // summary:
                        //              A *very* helpful method. If you know the center
                        //              (or starting) point, length and angle, find the
                        //              x,y point at the end of that line.

                        var radians =  angle * Math.PI / 180.0;
                        var x = radius * Math.cos(radians);
                        var y = radius * Math.sin(radians);
                        return {
                                x:cx+x,
                                y:cy-y
                        }; // Object
                },
                
                constrainAngle: function(/*EventObject*/obj, /*Number*/min, /*Number*/max){
                        // summary:
                        //              Ensures the angle in the Mouse Object is within the
                        //              min and max limits. If not one of those limits is used.
                        //              Returns an x,y point for the angle used.

                        var angle = this.angle(obj);
                        if(angle >= min && angle <= max){
                                return obj;      // Object
                        }
                        var radius = this.length(obj);
                        var new_angle = angle > max ? max : min - angle < 100 ? min : max;
                        return this.pointOnCircle(obj.start.x,obj.start.y,radius, new_angle); // Object
                },
                
                snapAngle: function(/*EventObject*/ obj, /*Float*/ ca){
                        // summary:
                        //              Snaps a line to the nearest angle
                        // obj: Mouse object (see dojox.drawing.Mouse)
                        // ca: Fractional amount to snap to
                        //              A decimal number fraction of a half circle.
                        //
                        //              - .5 would snap to 90 degrees
                        //              - .25  would snap to 45 degrees
                        //              - .125 would snap to 22.5 degrees, etc.

                        var radians = this.radians(obj),
                                radius = this.length(obj),
                                seg = Math.PI * ca,
                                rnd = Math.round(radians/seg),
                                new_radian = rnd*seg,
                                new_angle = this.radToDeg(new_radian),
                                pt = this.pointOnCircle(obj.start.x,obj.start.y,radius,new_angle);
                        return pt;  // Object
                },
                
                // helpers
                idSetStart: function(num){
                        start=num;
                },
                
                uid: function(/*String?*/ str){
                        // summary:
                        //              Creates a unique ID.
                        // str: String
                        //              If provided, kept in a map, incremented
                        //              and used in the id. Otherwise 'shape' is used.

                        str = str || "shape";
                        uidMap[str] = uidMap[str]===undefined ? start : uidMap[str] + 1;
                        return str + uidMap[str]; // String
                },
                
                abbr: function(type){
                        // summary:
                        //              Converts a namespace (typically a tool or a stencil) into
                        //              an abbreviation
                        return type.substring(type.lastIndexOf(".")+1).charAt(0).toLowerCase()
                                + type.substring(type.lastIndexOf(".")+2);
                },
                mixin: function(o1, o2){
                        // TODO: make faster
                        //return dojo.mixin(dojo.clone(o1), dojo.clone(o2));
                },
                
                objects:{}, //private?
                register: function(/*Object*/obj){
                        // summary:
                        //              Since util is the only Singleton in Drawing (besides
                        //              keys) it is used to help connect the Drawing object
                        //              the Toolbar. Since multiple drawings can be on one
                        //              page, this function serves a little more use than
                        //              on first apearance.
                        this.objects[obj.id] = obj;
                },
                byId: function(/*String*/id){
                        // summary:
                        //              Get an object that was registered with util.register

                        return this.objects[id];
                },
                attr: function(/* Object */ elem, /* property */ prop, /* ? value */ value, squelchErrors){
                        // summary:
                        //              Helper function to attach attributes to SVG and VML raw nodes.

                        
                        if(!elem){ return false; }
                        try{
                                
                                // util is a crappy check, but we need to tell the diff
                                // between a Drawing shape and a GFX shape
                                if(elem.shape && elem.util){
                                        elem = elem.shape;
                                }
                                
                                if(!value && prop=="id" && elem.target){
                        
                                        var n = elem.target;
                                        while(n && !dojo.attr(n, "id")){
                                                n = n.parentNode;
                                        }
                                        return n && dojo.attr(n, "id");
                                }
                                
                                if(elem.rawNode || elem.target){
                                        var args = Array.prototype.slice.call(arguments);
                                        args[0] = elem.rawNode || elem.target;
                                        return dojo.attr.apply(dojo, args);
                                }
                                return dojo.attr(elem, "id");
                                
                                
                                
                        }catch(e){
                                if(!squelchErrors){
                                        // For debugging only. These errors actually cause errors in IE's console
                                        //console.error("BAD ATTR: prop:", prop, "el:", elem)
                                        //console.error(e)
                                        //console.trace();
                                }
                                return false;
                        }
                }
        };
        
});