canvas-star7.html - 秒客网

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>添加土地</title>

</head>

<body>

    <canvas id="canvas" style="margin:0 auto;">

        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 = 1200;

            canvas.height = 800;

            if(canvas.getContext('2d')){

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

                // context.fillStyle = "#000";

                // 背景

                var skyStyle = context.createRadialGradient(canvas.width/2,canvas.height,0,canvas.width/2,canvas.height,canvas.height);

                skyStyle.addColorStop(0.0,'#035');

                skyStyle.addColorStop(1.0,'black');

                context.fillStyle = skyStyle;

                context.fillRect(0,0,canvas.width,canvas.height)

                // 星星

                for(var i=0;i<200;i++){

                    var r = Math.random() * 5 + 5;

                    var x = Math.random() * canvas.width;

                    var y = Math.random() * canvas.height * 0.65;

                    var a = Math.random() * 360;

                    drawStar(context , x , y , r , a )

                }

                // 月亮

                fillMoon(context,2,900,200,100,30)

                // 土地

                drawLand(context)

            }else{

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

            }

        }

        function drawLand(cxt){

            cxt.save();

                cxt.beginPath();

                    cxt.moveTo(0,600);

                    cxt.bezierCurveTo(540,400,660,800,1200,600);

                    cxt.lineTo(1200,800);

                    cxt.lineTo(0,800);

                cxt.closePath();

                var landStyle = cxt.createLinearGradient(0,800,0,0);

                landStyle.addColorStop(0.0,'#030');

                landStyle.addColorStop(1.0,'#580');

                cxt.fillStyle = landStyle;

                cxt.fill();

            cxt.restore();

        }

        function fillMoon(cxt,d,x,y,R,rot,fillColor){

            cxt.save();

                cxt.translate(x,y);

                cxt.rotate(rot*Math.PI/180);

                cxt.scale(R,R);

                pathMoon(cxt,d);

                cxt.fillStyle = fillColor || "#fb5";

                cxt.fill();

            cxt.restore();

        }

        function pathMoon(cxt,d){

            cxt.beginPath();

                cxt.arc(0,0,1,0.5*Math.PI,1.5*Math.PI,true);

                moveTo(0,-1);

                cxt.arcTo(d,0,0,1,dis(0,-1,d,0)/d);

            cxt.closePath();

        }

        function dis(x1,y1,x2,y2){

            return Math.sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2))

        }

        function createBackgroundCanvas(){

            var backCanvas = document.createElement("canvas");

            backCanvas.width = 100;

            backCanvas.height = 100;

            var backCanvasContext = backCanvas.getContext('2d');

            drawStar(backCanvasContext,50,50,50,0);

            return backCanvas

        }

        function drawStar(cxt,x,y,R,rot){

            cxt.save();

                cxt.translate(x,y);

                cxt.rotate(rot/180*Math.PI);

                cxt.scale(0.05*R,0.05*R)

                starPath(cxt);

                cxt.fillStyle = "#fb3";

                cxt.strokeStyle = "#fd5";

                cxt.lineWidth = 3;

                cxt.lineJoin = "round";

                cxt.fill();

                cxt.stroke();

            cxt.restore()

        }

        function starPath(cxt){

            cxt.beginPath();

            for(var i=0;i<5;i++){

                cxt.lineTo(Math.cos( (18+i*72) / 180 * Math.PI )*20,

                                -Math.sin( (18+i*72) / 180 * Math.PI )*20);

                cxt.lineTo(Math.cos( (54+i*72) / 180 * Math.PI )*0.5*20,

                                -Math.sin( (54+i*72) / 180 * Math.PI )*0.5*20);

            }

            cxt.closePath();

        }

    </script>

</body>

<script>

    /*图形变换

        位移 translate(x,y)

        旋转 rotate(deg)

        缩放 scale(sx,sy)

    */

</script>

</html>