canvas-9NonZeroAroundPrinciples2.html-优快云博客

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>非零环绕原则</title>
</head>
<body>
    <canvas id="canvas" style="margin:0 auto;border:1px #ddd solid">
        The current browser does not support Canvas, can replace the browser a try!
    </canvas>

    <script>

        window.onload = function(){
            var canvas = document.getElementById('canvas');

            canvas.width = 1024;
            canvas.height = 768;

            if(canvas.getContext('2d')){
                var context = canvas.getContext('2d');

                context.beginPath();
                    context.rect(100,100,600,600);
                    pathRect(context,200,200,400,200);
                    pathTriangle(context,300,450,150,650,450,650);
                    context.arc(550,550,100,0,Math.PI*2,true);
                context.closePath();

                context.fillStyle = "#058";
                context.shadowColor = "gray";
                context.shadowOffsetX = 10;
                context.shadowOffsetY = 10;
                context.shadowBlur = 10;
                context.fill();

            }else{
                alert('当前游览器不支持Canvas，请更换游览器后再试！');
            }
        }

        function pathRect(cxt,x,y,width,height){
                cxt.moveTo(x,y);
                cxt.lineTo(x,y+height);
                cxt.lineTo(x+width,y+height);
                cxt.lineTo(x+width,y)
                cxt.lineTo(x,y);
        }

        function pathTriangle(cxt,x1,y1,x2,y2,x3,y3){
                cxt.moveTo(x1,y1);
                cxt.lineTo(x2,y2);
                cxt.lineTo(x3,y3);
                cxt.lineTo(x1,y1);
        }

    </script>
</body>

</html>