可喜可贺！庆祝电脑起死回生，庆祝一天好过一天。深夜给电脑安装了开发插件，第二天莫名死机，问了好多人都说主板坏掉了，需要重装系统。我先是对着 宾夕法尼亚大学 的方向拜了拜，又是一番操作，终于唤醒了老伙计度假的心。 写一个Canvas 动画送给你们，十五的月亮十六圆，多给家人一些陪伴。
今晚我会出一期Canvas 动画详细教程，如果你欣赏我的动画，我将不胜感激。 请看源码：
代码语言：javascript复制<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="UTF-8">
<title>Canvas 网状花环</title>
<style>
html, body {
margin: 0;
overflow: hidden;
}
</style>
</head>
<body>
<canvas id="canvas" width="100%" height="100%">
</body>
<script>
var canvas = document.querySelector("#canvas");
var ctx = canvas.getContext("2d");
var mouseX = 0;
var mouseY = 0;
var a = 0.2;
var t = 0;
var aStep = Math.PI * 0.01;
var globalHue = 0;
init();
function init() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
window.addEventListener("mousemove", e => {
mouseX = e.clientX;
mouseY = e.clientY;
});
update();
}
function update() {
requestAnimationFrame(update);
var time = performance.now() / 60;
// do stuff here
a = Math.sin(2 - time * 0.0001);
t = Math.sin(2 time * 0.03);
//aStep = (Math.sin(time * 0.01) 1.5) * 0.25
aStep = Math.PI * (0.375 Math.sin(time * 0.001) * 0.125);
globalHue = 10;
draw();
}
function draw() {
// clear canvas
ctx.fillStyle = "#000000";
ctx.fillRect(0, 0, canvas.width, canvas.height);
// line
var cx = window.innerWidth / 2;
var cy = window.innerHeight / 2;
var x, y, px, py;
var radius = 0,pradius = 0;
var totalAngle = Math.PI * 200;
for (var theta = 0; theta < totalAngle; theta = aStep) {
pradius = radius;
radius = (t Math.pow(2, Math.cos(theta * a))) * 200;
px = x;
py = y;
x = cx Math.cos(theta) * radius;
y = cy Math.sin(theta) * radius;
if (theta > 0) {
ctx.beginPath();
ctx.moveTo(x, y);
ctx.lineTo(px, py);
var dx = x - px;
var dy = y - py;
var lineSize = Math.sqrt(dx * dx dy * dy);
var r = pradius (radius - pradius) / 2;
var hue = globalHue theta / Math.PI * 180;
ctx.strokeStyle = "hsl(" hue ", 100%, 50%)";
//ctx.lineWidth=clamp(map(r, -200, 200, 0.25, 2), 0.25, 10);
ctx.lineWidth = .5;
ctx.stroke();
ctx.closePath();
}
}
}
function map(value, start1, stop1, start2, stop2) {
return start2 (stop2 - start2) * ((value - start1) / (stop1 - start1));
}
function clamp(value, min, max) {
return value < min ? min : value > max ? max : value;
}
</script>
</html>无论是Canvas 还是别的，前端的学习总是妙趣横生，只要思想在不断进步，技术就会一次次的突破。如果你学习过Canvas ，你会更加了解这段代码的神奇，送给你，远道而来的求学者。
