在HTML画布上绘制线宽连续变化的线
要绘制线宽连续变化的线，可以尝试运行以下代码-
示例
var context = document.getElementById('canvas1').getContext('2d');
var pts = [null, null, null, null];
for(var i=-1; i<25; i=i+1)
{
var width = 0.5+i/2;
var m = 200;
var x = Math.cos(i/4) * 180;
var y = Math.sin(i/4) * 140;
pts[0] = pts[1];
pts[1] = pts[2];
pts[2] = { X:x, Y:y};
if(pts[0] == null)
continue;
var p0 = pts[0];
var p1 = pts[1];
var p2 = pts[2];
var x0 = (p0.X + p1.X) / 2;
var y0 = (p0.Y + p1.Y) / 2;
var x1 = (p1.X + p2.X) / 2;
var y1 = (p1.Y + p2.Y) / 2;
context.beginPath();
context.lineWidth = width;
context.strokeStyle = "blue";
context.moveTo(m+x0, m+y0);
context.quadraticCurveTo(m+p1.X, m+p1.Y, m+x1, m+y1);
context.stroke();
}