音波 - 简书

你可以把shout.mp3 换成你喜欢的音乐
注意：现在好像是chorme为了安全，不能直接打开，需要通过服务器（使用localhost打开）
<!DOCTYPE html>
<html>
        <head>
                <meta charset="utf-8" />
                <title></title>
        </head>
        <body onload="init()">
        <canvas id="canvasOne"  width="840px"></canvas>
                <audio src="shout.mp3" autoplay="autoplay" controls="controls" id="Audioa"></audio>
                
                <script>
                                var canvas;
                                var audio1;
                        
                                var ctx;
                                var Analyser;
                                function init(){
                                        audio1 = document.getElementById("Audioa");
                                        canvas = document.getElementById("canvasOne");
                                        ctx = canvas.getContext("2d");
                                        audioctx= new(window.AudioContext|| window.webkitAudioContext);
                                        Analyser =audioctx.createAnalyser();
                                        source=audioctx.createMediaElementSource(audio1);
                                        source.connect(Analyser);
                                        Analyser.connect(audioctx.destination);
                                        draw();
                                }
                                function draw(){
                                        var width = canvas.width;
                                        var height = canvas.height;
                                        var        array1 = new Uint8Array(128);
                                        Analyser.getByteFrequencyData(array1);
                                
                                        grd=ctx.createLinearGradient(0,0,0,300);
                                        grd.addColorStop(0,"red");
                                        grd.addColorStop(1,"yellow");
                                        ctx.clearRect(0,0,width,height);
                                        
                                        for(var i = 1; i<array1.length;i++)
                                        {
                                                ctx.fillStyle=grd;
                                                ctx.fillRect(i * 5,height-array1[i]+100,3,height+300);
                                        }
                                        
                                        requestAnimationFrame(draw);
                                }
                        
                </script>
                
                
                
        </body>
</html>