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water-canvas.html
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water-canvas.html
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<!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>
<style>
html,
body {
padding: 0;
margin: 0;
width: 100%;
height: 100%;
overflow: hidden;
}
</style>
</head>
<body>
<script>
// 正弦曲线公式：y = A sin(Bx + C) + D
// A 控制振幅，A 值越大，波峰和波谷越大，A 值越小，波峰和波谷越小；// 振幅是 A，A 值越大，曲线更陡峭
// B 值会影响周期，B 值越大，那么周期越短，B 值越小，周期越长。// 周期是 2π/B，B 值大于 1 时，B 值越大，周期越短，B 值小于 1 大于 0 时，周期变长
// C 值会影响图像左右移动，C 值为正数，图像右移，C 值为负数，图像左移。 // 相移是 −C/B，在 B 不变的情况，C 为正值时，曲线向左移动，C 为负值时，曲线向右移动：
// D 值控制上下移动。// 垂直位移是 D，控制曲线上下移动：
window.onload = function () {
'use strict';
const canvas = {
init() {
this.ele = document.createElement('canvas');
document.body.appendChild(this.ele);
this.ele.style.width = window.innerWidth + 'px';
this.ele.style.height = window.innerHeight + 'px';
this.ele.width = window.innerWidth;
this.ele.height = window.innerHeight;
// this.ele.style.background = '#f1513b';
const ctx = this.ele.getContext('2d');
// return ctx;
// this.drawSin(ctx);
this.xOffset = 0; // 初始偏移
this.speed = 0.1; // 偏移速度
// 水位数值
this.rangeValue = 0.7;
// 初始水位
this.nowRange = 0;
requestAnimationFrame(this.draw.bind(this, this.ele));
},
draw() {
const canvas = this.ele;
const ctx = canvas.getContext('2d');
ctx.clearRect(0, 0, canvas.width, canvas.height);
if (!this.isDrawCircle) {
this.drawCircle(ctx);
}
if (this.nowRange < this.rangeValue) {
this.nowRange += 0.01;
}
// 曲线绘制
this.drawSin(ctx, 8, this.xOffset + 10, 0.08, this.nowRange, "#ff2d55");
this.drawSin(ctx, 5, this.xOffset + 25, 0.000, this.nowRange, "#ff2d44");
// this.xOffset += this.speed;
requestAnimationFrame(this.draw.bind(this));
},
drawCircle(ctx) {
const cirX = window.innerWidth / 2;
const cirY = window.innerHeight / 2;
const lineWidth = 5;
const cirR = cirX - lineWidth;
ctx.beginPath();
ctx.arc(cirX, cirY, cirR, 0, 2 * Math.PI);
ctx.stroke();
ctx.clip(); // 只显示此圆区域
this.isDrawCircle = true;
},
drawSin(ctx, wheight, xOffset, speed, nowRange, color) {
const points = [];
console.log(ctx)
const canvasWidth = window.innerWidth;
const canvasHeight = window.innerHeight;
const startX = 0;
const waveHeight = wheight; // 波浪高度,数越大越高
const waveWidth = 0.05; // 波浪宽度,数越小越宽
// const xOffset = 0; // 水平位移
ctx.beginPath();
for (let x = startX; x < startX + canvasWidth; x += 20 / canvasWidth) {
const y = waveHeight * Math.sin((startX + x) * waveWidth + xOffset);
// points.push([x, (canvasHeight / 2) + y]);
// ctx.lineTo(x, (canvasHeight / 2) + y);
points.push([x, ((1 - nowRange) * canvasHeight) + y]);
ctx.lineTo(x, ((1 - nowRange) * canvasHeight) + y);
}
ctx.lineTo(canvasWidth, canvasHeight);
console.log('current startX:' + startX)
ctx.lineTo(startX, canvasHeight);
// ctx.lineTo(points[0][0], points[0][1]);
ctx.lineTo(0, points[0][1])
ctx.stroke();
// 修改填充色
const radius = canvasWidth / 2
const grd = ctx.createLinearGradient(radius, radius, radius, canvasHeight);
grd.addColorStop(0, '#F39C6B');
grd.addColorStop(1, '#A0563B');
ctx.fillStyle = grd;
ctx.fill();
// 修改偏移速度
this.xOffset += speed;
}
}
canvas.init();
}
</script>
</body>
</html>