<!DOCTYPE html><html><head> <title>星空</title> <script type="text/javascript"> function draw() { var canvas=document.getElementById("canvas"); var context=canvas.getContext("2d"); context.fillStyle="black"; context.fillRect(0,0,canvas.width,canvas.height); for(var i=0;i<20;i++){ var r=Math.random()*10+10; var x=Math.random()*canvas.width; var y=Math.random()*canvas.height; var a=Math.random()*360; drawStar(context,x,y,r,r/2.3,a) } } function drawStar(cxt,x,y,r,R,rot) { cxt.beginPath(); for(var i=0;i<5;i++){ cxt.lineTo(Math.cos((18+i*72-rot)/180*Math.PI)*R+x,-Math.sin((18+i*72-rot)/180*Math.PI)*R+y); cxt.lineTo(Math.cos((54+i*72-rot)/180*Math.PI)*r+x,-Math.sin((54+i*72-rot)/180*Math.PI)*r+y); } cxt.fillStyle="yellow" cxt.closePath(); cxt.fill(); } </script> <style type="text/css"> </style></head><body onload="draw()";><canvas id="canvas" width="800" height="400"></canvas></body></html>
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