canvas-3linearGradient.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</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 = 800;
            canvas.height = 800;

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

                // begin
                var linearGrad = context.createLinearGradient(0,0,200,800);
                linearGrad.addColorStop(0.0,'white');
                linearGrad.addColorStop(0.25,'yellow');
                linearGrad.addColorStop(0.5,'green');
                linearGrad.addColorStop(0.75,'blue');
                linearGrad.addColorStop(1.0,'black');
                context.fillStyle = linearGrad;
                context.fillRect(0,0,800,800)

            }else{
                alert('当前游览器不支持Canvas,请更换游览器后再试!');
            }
        }
    </script>
</body>
<script>
    /*总结
    step 1
        //修改xstart,ystart,xend,yend 改变渐变方向
        //修改fillRect 改变渐变区域
        var grd = context.creatLinearGradient(xstart,ystart,xend,yend)
    step 2
        //stop的值域[0,1]
        grd.addColorStop(stop,color)
    */
</script>
</html>
原文地址:https://www.cnblogs.com/cynthia-wuqian/p/4981636.html