WX20200719-132412@2x.png
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<canvas id="myCanvas"></canvas>
<script>
var WAVE_HEIGHT = 200 //波浪变化高度
var SCALE = 1 // 绘制速率
var CYCLE = 360 // SCALE
var TIME = 0
function initCanvas() {
var c = document.getElementById("myCanvas")
var width = window.screen.width
var height = window.screen.height
var ctx = c.getContext("2d")
c.width = width
c.height = height
// start
window.requestAnimationFrame(function() {
console.log(new Date().getTime())
console.log(123)
draw(ctx, width, height)
})
}
function draw(ctx, width, height) {
ctx.clearRect(0, 0, width, height)
TIME = (TIME + 1)
var angle = SCALE * TIME // 当前正弦角度
var dAngle = 60 // 两个波峰相差的角度
ctx.beginPath()
ctx.moveTo(0, height * 0.4 + distance(WAVE_HEIGHT, angle, 0))
ctx.bezierCurveTo(
width * 0.4,
height * 0.5 + distance(WAVE_HEIGHT, angle, dAngle),
width * 0.6,
height * 0.5 + distance(WAVE_HEIGHT, angle, 2 * dAngle),
width,
height * 0.5 + distance(WAVE_HEIGHT, angle, 3 * dAngle)
)
ctx.lineTo(2000,1600);
ctx.lineTo(0,1600);
ctx.closePath();
ctx.fillStyle = "rgba(24, 207, 196, 1.0)";
ctx.fill();
ctx.strokeStyle = "yellow"
ctx.stroke()
//第二条
ctx.beginPath()
ctx.moveTo(0, height * 0.5 + distance(WAVE_HEIGHT, angle, -30))
ctx.bezierCurveTo(
width * 0.3,
height * 0.5 + distance(WAVE_HEIGHT, angle, dAngle),
width * 0.7,
height * 0.5 + distance(WAVE_HEIGHT, angle, 2 * dAngle),
width,
height * 0.5 + distance(WAVE_HEIGHT, angle, 3 * dAngle)
)
ctx.lineTo(2000,1600);
ctx.lineTo(0,1600);
ctx.closePath();
ctx.fillStyle = 'rgba(39, 239, 159, 1.0)';
ctx.fill();
ctx.strokeStyle = "yellow"
ctx.stroke()
//disi
ctx.beginPath()
ctx.moveTo(0, height * 0.5 + distance(WAVE_HEIGHT, angle, 30))
ctx.bezierCurveTo(
width * 0.1,
height * 0.5 + distance(WAVE_HEIGHT, angle, dAngle),
width * 0.5,
height * 0.5 + distance(WAVE_HEIGHT, angle, 2 * dAngle),
width,
height * 0.5 + distance(WAVE_HEIGHT, angle, 3 * dAngle)
)
ctx.lineTo(2000,1600);
ctx.lineTo(0,1600);
ctx.closePath();
ctx.fillStyle = 'rgba(0, 158, 252, 1.0)';
ctx.fill();
ctx.strokeStyle = "yellow"
ctx.stroke()
function distance(height, currAngle, diffAngle) {
return height * Math.cos((((currAngle - diffAngle) % 360) * Math.PI * 2) / 360)
}
// animate
window.requestAnimationFrame(function() {
draw(ctx, width, height)
})
}
initCanvas()
</script>
</body>
<style>
body{
background: skyblue;
}
*{
margin: 0;
padding: 0;
}
</style>
</html>
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