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<html> <head> </head> <body> <canvas height="600" width="800" id="canvas" /> <script type="text/javascript"> function Point(x,y) { this.x = x; this.y = y; } function Line(p1,p2) { this.p1 = p1; this.p2 = p2; this.length = Math.sqrt(Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2)); /////////error here******************** } function Shape() { this.points = []; ///////////// this.lines = []; ////////////// this.init(); } Shape.prototype = { constructor:Shape, init: function() { if(typeof this.context === 'undefined') { var canvas = document.getElementById('canvas'); Shape.prototype.context = canvas.getContext('2d'); } }, draw: function() { var ctx = this.context; ctx.strokeStyle = this.getColor(); ctx.beginPath(); ctx.moveTo(this.points[0].x, this.points[0].y); for(var i=1; i<this.points.length; i++) ctx.lineTo(this.points[i].x, this.points[i].y); ctx.closePath(); ctx.stroke(); }, getColor: function() { var rgb = []; for(var i=0; i<3; i++) rgb[i] = Math.round(255*Math.random()) return 'rgb('+ rgb.join(',') + ')'; }, getLines: function() /////////////// { if(this.lines.length > 0) return this.lines; var lines = []; for(var i=0; this.points.length; i++) lines[i] = new Line(this.points[i], (this.points[i+1])?this.points[i+1]:this.points[0]); this.lines = lines; this.lines; return lines; }, getArea: function(){}, getPerimeter: function() //////////////// { var lines = this.getLines(); var perim = 0; for(var i=0; i<=lines.length; i++) perim +=lines[i].length; } } function Triangle(a,b,c) { this.points = [a,b,c]; this.getArea = function() { var p = this.getPerimeter(); var s = p/2; return Math.sqrt(s*(s-this.lines[0].length)*(s-this.lines[1].length)*(s-this.lines[2].length)); } } function Rectangle(p, side_a, side_b) { this.points = [p, new Point(p.x + p.y), new Point(p.x + side_a, p.y + side_b), new Point(p.x, p.y + side_b)]; this.getArea = function() { return side_a * side_b; } } function Square(p, side) { Rectangle.call(this, p, side, side); } (function(){ var s =new Shape(); Triangle.prototype = s; Rectangle.prototype = s; Square.prototype = s; })() var p1 = new Point(100,100); var p2 = new Point(300,100); var p3 = new Point(200,0); var t = new Triangle(p1, p2, p3); t.draw(); t.getPerimeter(); /////////////// //t.getArea(); </script> </body> </html>
Отредактировано Shutnik (07-03-2009 19:30:48)
Отсутствует
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