canvas动画，线条被重复绘制该如何解决

Question

请问为什么会出现，所绘线条颜色被加深、粗细不一，感觉前面的被重绘了？我该如何解决来避免这个问题

代码如下

 var c=document.getElementById("myCanvas");
var context=c.getContext("2d");
context.strokeStyle="RGBA(255,0,0,.1)"
var point=[[5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25],[-2,-2,-7,-2,-7,-1,-6,-3,-6,-7,-6,-8,-0,-0,-1,-0,-5,-8,-5,-4,-6]]
            var k=0
            var f=setInterval(function(){
                if(k>20){
                    clearInterval(f)
                }else{
                    context.lineTo((point[0][k]-5)*20,point[1][k]*-26)
                   context.stroke()
                }
                k++
            },100)

Answer 1

var c = document.getElementById("myCanvas");
var context = c.getContext("2d");
context.strokeStyle = "RGBA(255,0,0,.1)"
##context.beginPath()
var point = [
[5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25],
[-2, -2, -7, -2, -7, -1, -6, -3, -6, -7, -6, -8, -0, -0, -1, -0, -5, -8, -5, -4, -6]
]
var k = 0
var f = setInterval(function() {
if (k > 20) {
context.stroke()
## clearInterval(f)
} else {
## context.moveTo((point[0][k] - 5) * 20, point[1][k] * -26)
## context.lineTo((point[0][k+1] - 5) * 20, point[1][k+1] * -26)
}
k++
}, 0)
});
的确是被重绘了，加##的地方是要注意的地方。