水平和比例调整正弦波的大小 - js

Question

我不知道在调整窗口大小时水平调整正弦波大小并缩小比例的正确方法。它仍然需要在垂直的同一位置，我现在只需要水平和比例调整大小。正弦波显示在这个js-fiddle中： https://jsfiddle.net/x2audoqk/7/

正弦波的JS代码：

const canvas = document.querySelector("canvas")
const c = canvas.getContext("2d")
canvas.width = innerWidth
canvas.height = innerHeight
// Resize wave vertically
window.addEventListener("resize", () => {
canvas.width = innerWidth
canvas.height = innerHeight
wave.y = canvas.height / 1.5
})
const wave = {
y: canvas.height / 1.5,
length: -0.0045,
amplitude: 47.5,
frequency: 0.0045
}
let increment = wave.frequency
const animate = () => {
requestAnimationFrame(animate)
// Deletes previous waves
c.clearRect(0, 0, canvas.width, canvas.height)
c.beginPath()
// Get all the points on the line so you can modify it with sin
for (let i = 0; i <= canvas.width; i++) {
c.moveTo(i, wave.y + Math.sin(i * wave.length + increment) * wave.amplitude * Math.sin(increment))
c.lineTo(i, canvas.height)
}
// Style
c.strokeStyle = 'rgba(1, 88, 206, .25)'
c.stroke()
increment += wave.frequency
c.closePath()
}
animate()

我如何实现这一点？如果您需要更多信息或澄清，请随时询问。

Answer 1

我不知道这是否是你想要的，

但是通过添加这条线，波浪的长度适合画布的宽度

window.addEventListener("resize", function () {
canvas.width = innerWidth
canvas.height = innerHeight
wave.y = canvas.height / 1.5
wave.length = -2/canvas.width // <---- add this line
})

https://jsfiddle.net/gui3_/mwzun5dr/1/

编辑

为了使其干净，还应该更改以下内容，以便在调整大小之前波的长度与计算相同

const wave = {
y: canvas.height / 1.5,
length: -2/canvas.width, //-0.0045,
amplitude: 47.5,
frequency: 0.0045
}