2011-09-02 79 views
0

我可以创建线条,但是我想创建线条,就像您可以改变线条的方向和线的大小,就像这个链接中的http://devfiles.myopera.com/articles/649/example5.html一样。HTML5画布线问题

这是我的代码

var canvas = document.getElementById("canvas"); 
var context = canvas.getContext("2d"); 
$("canvas").mousedown(function(e) { 
    var x = e.pageX - this.offsetLeft; 
    var y = e.pageY - this.offsetTop; 
    var a = x; 
    var b = y; 
    context.beginPath(); 
    context.lineWidth = 2; 
    context.lineCap = "round"; 
    context.moveTo(a, b); 
    $("canvas").mousemove(function(e) { 
     var x = e.pageX - this.offsetLeft; 
     var y = e.pageY - this.offsetTop; 
     context.lineTo(x, y); 
     context.stroke(); 
    }); 
    $("canvas").mouseup(function(e) { 
     $("canvas").unbind("mousemove").unbind("mouseup"); 
    }); 
}); 

您也可以看看从。 http://jsfiddle.net/nSnDC/我该如何解决呢

回答