📅  最后修改于: 2023-12-03 15:00:37.412000             🧑  作者: Mango
ES6动画是指使用ES6语法实现的动画效果。ES6在语言层面上提供了更加丰富和灵活的方式来实现动画效果,相较于传统的jQuery动画,ES6动画更加简洁易懂,且动画效果更加流畅自然。本文将介绍ES6动画的实现原理及示例。
ES6动画的实现依赖于requestAnimationFrame
函数,这个函数是浏览器提供的一个方法,用于循环执行指定的动画操作。使用requestAnimationFrame
函数来执行动画操作具有以下优点:
以下是一个基于ES6的动画示例,使用requestAnimationFrame
函数来实现动画效果。
class Animation {
constructor({ duration = 1000, onStart, onProgress, onEnd }) {
this.startTime = null;
this.endTime = null;
this.duration = duration;
this.onStart = onStart;
this.onProgress = onProgress;
this.onEnd = onEnd;
this.requestId = null;
}
start() {
this.startTime = performance.now();
this.endTime = this.startTime + this.duration;
if (typeof this.onStart === "function") {
this.onStart();
}
this.requestId = requestAnimationFrame((timestamp) => {
this.tick(timestamp);
});
}
tick(timestamp) {
const progress = (timestamp - this.startTime) / this.duration;
if (progress >= 1) {
if (typeof this.onProgress === "function") {
this.onProgress(1);
}
if (typeof this.onEnd === "function") {
this.onEnd();
}
} else {
if (typeof this.onProgress === "function") {
this.onProgress(progress);
}
this.requestId = requestAnimationFrame((timestamp) => {
this.tick(timestamp);
});
}
}
stop() {
cancelAnimationFrame(this.requestId);
}
reset() {
this.startTime = null;
this.endTime = null;
this.requestId = null;
}
}
以上示例中定义了一个Animation类,该类接收一个配置对象,其中包含了动画的时间长度、开始、进行中和结束时的回调函数,以及如何更新动画状态的方法等。类中的start
方法用于启动动画,stop
方法用于停止动画,reset
方法用于重置动画状态。
下面是一个基于ES6的圆形旋转动画示例,代码解释在注释中。
const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");
class Circle {
constructor({ x, y, radius, color }) {
this.x = x;
this.y = y;
this.radius = radius;
this.color = color;
}
draw() {
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, true);
ctx.closePath();
ctx.fillStyle = this.color;
ctx.fill();
}
}
class Animation {
constructor({ duration = 1000, onStart, onProgress, onEnd }) {
this.startTime = null;
this.endTime = null;
this.duration = duration;
this.onStart = onStart;
this.onProgress = onProgress;
this.onEnd = onEnd;
this.requestId = null;
}
start() {
this.startTime = performance.now();
this.endTime = this.startTime + this.duration;
if (typeof this.onStart === "function") {
this.onStart();
}
this.requestId = requestAnimationFrame((timestamp) => {
this.tick(timestamp);
});
}
tick(timestamp) {
const progress = (timestamp - this.startTime) / this.duration;
if (progress >= 1) {
if (typeof this.onProgress === "function") {
this.onProgress(1);
}
if (typeof this.onEnd === "function") {
this.onEnd();
}
} else {
if (typeof this.onProgress === "function") {
this.onProgress(progress);
}
this.requestId = requestAnimationFrame((timestamp) => {
this.tick(timestamp);
});
}
}
stop() {
cancelAnimationFrame(this.requestId);
}
reset() {
this.startTime = null;
this.endTime = null;
this.requestId = null;
}
}
const circle = new Circle({
x: canvas.width / 2,
y: canvas.height / 2,
radius: 50,
color: "#3498db",
});
const animation = new Animation({
duration: 3000,
onProgress: (progress) => {
// 更新圆的位置和状态
const angle = progress * Math.PI * 2;
const x = canvas.width / 2 + 60 * Math.cos(angle);
const y = canvas.height / 2 + 60 * Math.sin(angle);
circle.x = x;
circle.y = y;
circle.radius = 50 - progress * 20;
// 刷新画布
ctx.clearRect(0, 0, canvas.width, canvas.height);
circle.draw();
},
});
animation.start();
ES6动画为我们提供了更加灵活和方便的动画效果实现方式,能够让我们在动画效果的设计和开发中更加得心应手。同时,ES6动画还能够提升动画效果的性能和流畅度,让我们的应用程序更加出色。