js动画-学习笔记

韭伍後

已于 2022-04-10 19:22:17 修改

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分类专栏： js css 文章标签： javascript

于 2022-04-10 14:52:54 首次发布

本文链接：https://blog.youkuaiyun.com/cai_niao5623/article/details/124078213

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1、匀速运动

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .box {
            width: 200px;
            height: 200px;
            background-color: saddlebrown;
            position: relative;
            left: -200px;
        }

        .btn {
            width: 60px;
            height: 40px;
            display: flex;
            justify-content: center;
            align-items: center;
            background-color: lightblue;
            position: absolute;
            top: 50%;
            right: -60px;
            transform: translateY(-50%);
        }
    </style>
</head>

<body>
    <div class="box">
        <span class="btn">动画</span>
    </div>

    <script>
        window.onload = function () {
            var box = document.querySelector('.box')
            var timer = null
            var speed = 0

            box.onmouseover = function () {
                move(this,0)
            }
            box.onmouseout = function () {
                move(this,-200)
            }

            function move(obj,end) {
                clearInterval(timer)
                speed = end > obj.offsetLeft ? 5:-5
                timer = setInterval(() => {
                    if (obj.offsetLeft === end) {
                        return clearInterval(timer)
                    }
                    obj.style.left = obj.offsetLeft + speed + 'px'
                }, 20)
            }
        }
    </script>
</body>

</html>

2、缓动运动

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .box {
            width: 200px;
            height: 200px;
            background-color: saddlebrown;
            position: relative;
            left: -200px;
        }

        .btn {
            width: 60px;
            height: 40px;
            display: flex;
            justify-content: center;
            align-items: center;
            background-color: lightblue;
            position: absolute;
            top: 50%;
            right: -60px;
            transform: translateY(-50%);
        }
    </style>
</head>

<body>
    <div class="box">
        <span class="btn">动画</span>
    </div>

    <script>
        window.onload = function () {
            var box = document.querySelector('.box')
            var btn = document.querySelector('.btn')
            var timer = null
            /*
                加速度speed = (结束状态 - 初始状态) / 系数
            */
            var speed = 0
            // 鼠标进入元素时候元素的最终状态值
            var end1 = 0
            // 鼠标移除元素时候元素的最终状态值
            var end2 = -200

            box.onmouseover = function () {
                move(this, end1)
            }

            box.onmouseout = function () {
                move(this, end2)
            }

            function move(obj, end) {
                clearInterval(timer)
                timer = setInterval(() => {
                    if (obj.offsetLeft === end) {
                        return clearInterval(timer)
                    }
                    speed = (end - obj.offsetLeft) > 0 ? speed = Math.ceil((end1 - obj.offsetLeft) / 20) : speed = Math.floor((end2 - obj.offsetLeft) / 20)
                    obj.style.left = obj.offsetLeft + speed + 'px'
                }, 30)
            }
        }
    </script>
</body>

</html>

3、透明度动画

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 200px;
            height: 200px;
            background-color: brown;
            opacity: 0.3;
         }
    </style>
</head>
<body>
    <div class="box"></div>
    <script>
        window.onload = function() {
            var box = document.querySelector('.box')
            var timer = null,speed=0,alpha = 30

            box.onmouseover = function() {
                opacityAnimation(this,100)
            }

            box.onmouseout = function() {
                opacityAnimation(this,30)
            }

            function opacityAnimation(obj,end) {
                clearInterval(timer) 
                timer = setInterval(()=>{
                    if(alpha === end) return clearInterval(timer)
                    speed = end > alpha ? 10 : -10
                    alpha += speed
                    obj.style.opacity = alpha / 100
                },50)
            }
        }
    </script>
</body>
</html>

4、多物体缓动运动

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        div {
            width: 300px;
            height: 150px;
            background-color: chartreuse;
            margin: 15px 0;
            border: 1px solid #ccc;
        }
    </style>
</head>
<body>
    <div></div>
    <div></div>
    <div></div>
    <script>
        window.onload = function() {
            var oDivs = document.querySelectorAll('div')
            for(let i=0;i<oDivs.length;i++) {
                oDivs[i].onmouseover = function() {
                    changeWidth(this,600)
                }

                oDivs[i].onmouseout = function() {
                    changeWidth(this,300)
                }
            }

            var speed = 0;
            function changeWidth(obj,end) {
                // 对于多物体，定时器的返回值要绑定到当前对象里去
                clearInterval(obj.timer)
                obj.timer = setInterval(()=>{
                    let oWidth = parseInt(getStyle(obj,'width'))
                    if(end === oWidth) return clearInterval(obj.timer)
                    speed = (end - oWidth) > 0 ? Math.ceil((end - oWidth) / 20) : Math.floor((end - oWidth) / 20)
                    obj.style.width = `${oWidth + speed}px`
                },20)
            }

            /**
             * 获取元素属性的值
             * obj: 当前元素对象
             * attr: 当前元素对象属性
            */
            function getStyle(obj, attr) {
                if (obj.currentStyle) {
                    // 兼容ie
                    return obj.currentStyle[attr];
                }else {
                    // 主流浏览器
                    return getComputedStyle(obj, null)[attr]
                }
            }
        }
    </script>
</body>
</html>

5、封装简单的动画框架

var speed = 0;
/**
 * 动画的函数
 * @param {Object} obj 当前的对象
 * @param {Object} attr 当前元素对象的属性
 * @param {Object} endTarget 末尾位置
 */
function startAnimation(obj, json, fn) {
	// 针对于多物体运动,定时器的返回值要绑定当前的对象中.
	clearInterval(obj.timer);
	obj.timer = setInterval(function() {
		var cur = 0;
		var flag = true; //标杆 如果true，证明所有的属性都到达终点值
		for (var attr in json) {
			// 0 获取样式属性
			// 透明度变化处理
			switch (attr) {
				case 'opacity':
					cur = Math.round(parseFloat(getStyle(obj, attr)) * 100);
					break;
				case 'scrollTop':
					cur = obj[attr]
					break;
				default:
					cur = parseInt(getStyle(obj, attr));
					break;
			}
			// 1.求速度
			speed = (json[attr] - cur) / 10;
			speed = json[attr] > cur ? Math.ceil(speed) : Math.floor(speed);
			// 2.临界处理
			if (json[attr] !== cur) {
				flag = false;
			}
			// 3.运动起来
			switch (attr) {
				case 'opacity':
					obj.style[attr] = `alpha(opacity: ${cur + speed})`;
					obj.style[attr] = (cur + speed) / 100;
					break;
				case 'scrollTop':
					obj.scrollTop = cur + speed;
				default:
					obj.style[attr] = cur + speed + 'px';
					break;
			}
		}

		if (flag) {
			clearInterval(obj.timer);
			if (fn) {
				fn();
			}
			return;
		}

	}, 30);
}
/**
 * 获取元素属性的函数
 * @param {Object} obj 当前元素对象
 * @param {Object} attr 当前元素对象的属性
 */
function getStyle(obj, attr) {
	if (obj.currentStyle) {
		// 兼容ie
		return obj.currentStyle[attr];
	} else {
		// 兼容主流浏览器
		return getComputedStyle(obj, null)[attr];
	}
}