This are 2 Components for Crafty, with this Components it is possible to display collision Polygons of Enteties

hitbox.js

//Draw Wired HitBox
Crafty.c("WiredHitBox", {
    init:function(){
        if (Crafty.support.canvas){ 
            var c = document.getElementById('HitBox');
            if(!c){
                c = document.createElement("canvas");
                c.id = 'HitBox';
                c.width = Crafty.viewport.width;
                c.height = Crafty.viewport.height;
                c.style.position = 'absolute';
                c.style.left = "0px";
                c.style.top = "0px";
                c.style.zIndex = '1000';
                Crafty.stage.elem.appendChild(c); 
            }
        }
        this.requires("Collision").bind("EnterFrame",function(){
            if(!c){
            var ctx = c.getContext('2d');
            ctx.beginPath(); 
            ctx.clearRect(0, 0, Crafty.viewport.width, Crafty.viewport.height);
            for(var p in this.map.points){
                ctx.lineTo(Crafty.viewport.x+this.map.points[p][0],Crafty.viewport.y+this.map.points[p][1]);  
            }
            ctx.closePath(); 
            ctx.stroke(); 
            }
        }); 
        return this;
    }
});
//Draw Solid Hitbox
Crafty.c("SolidHitBox", {
    init:function(){
        //If Browser Support Canvas
        if (Crafty.support.canvas){ 
             //Find HitBox Canvas Element
            var c = document.getElementById('HitBox');
            if(!c){
               //Create new one if not exists
                c = document.createElement("canvas");
                c.id = 'HitBox';
                c.width = Crafty.viewport.width;
                c.height = Crafty.viewport.height;
                c.style.position = 'absolute';
                c.style.left = "0px";
                c.style.top = "0px";
                c.style.zIndex = '1000';
                Crafty.stage.elem.appendChild(c); 
            }
        }
        this.requires("Collision").bind("EnterFrame",function(){
            if(!c){
            //Draw Canvas.polygon points
            var ctx = c.getContext('2d');
            
            ctx.beginPath(); 
            for(var p in this.map.points){
                ctx.lineTo(Crafty.viewport.x+this.map.points[p][0],Crafty.viewport.y+this.map.points[p][1]);  
            }
            ctx.closePath(); 
            ctx.fill(); 
            }
        }); 
        return this;
    }
});