vue 自定义指令实现点击波纹效果

利用css的 过渡和动画效果，点击时给目标元素追加span标签，通过改变span的opacity和scale即可实现类似水波扩散的效果

我们可以将其封装为自定义指令便于调用。

• 创建 src/directives/waves文件夹
• directives目录下创建index.js。waves文件夹下创建 index.js和waves.css

具体代码如下：

//  directives/index.js
export * from './waves'

// waves/index.js
import './waves.css'

export const waves = {
  bind(el, binding) {
    el.addEventListener('click', e => {
      const customOpts = Object.assign({}, binding.value)
      const opts = Object.assign({
        ele: el, // 波纹作用元素
        type: 'hit', // hit 点击位置扩散 center中心点扩展
        color: 'rgba(255,255,255,0.3)' // 波纹颜色
      }, customOpts)
      const target: HTMLElement = opts.ele
      if (target) {
        target.style.position = 'relative'
        target.style.overflow = 'hidden'
        // 返回的结果是包含完整元素的最小矩形，并且拥有left, top, right, bottom, x, y, width, 和 height
        const rect = target.getBoundingClientRect()
        console.log('rect: ', rect);
        let ripple = target.querySelector('.waves-ripple') as HTMLElement
        if (!ripple) {
          ripple = document.createElement('span')
          ripple.className = 'waves-ripple'
          ripple.style.height = ripple.style.width = Math.max(rect.width, rect.height) + 'px'
          target.appendChild(ripple)
        } else {
          ripple.className = 'waves-ripple'
        }
        switch (opts.type) {
          case 'center':
            ripple.style.top = rect.height / 2 - ripple.offsetHeight / 2 + 'px'
            ripple.style.left = rect.width / 2 - ripple.offsetWidth / 2 + 'px'
            break
          default:
            ripple.style.top =
              (e.pageY - rect.top - ripple.offsetHeight / 2 - document.documentElement.scrollTop ||
                document.body.scrollTop) + 'px'
            ripple.style.left =
              (e.pageX - rect.left - ripple.offsetWidth / 2 - document.documentElement.scrollLeft ||
                document.body.scrollLeft) + 'px'
        }
        ripple.style.backgroundColor = opts.color
        ripple.className = 'waves-ripple z-active'
        return false
      }
    }, false)
  }
}

// waves/waves.css
.waves-ripple {
    position: absolute;
    border-radius: 100%;
    background-color: rgba(255, 255, 255, 0.3);
    background-clip: padding-box;
    pointer-events: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    -webkit-transform: scale(0);
    -ms-transform: scale(0);
    transform: scale(0);
    opacity: 1;
    z-index: 999;
}

.waves-ripple.z-active {
    opacity: 0;
    -webkit-transform: scale(2);
    -ms-transform: scale(2);
    transform: scale(2);
    -webkit-transition: opacity 1.2s ease-out, -webkit-transform .3s ease-out;
    transition: opacity .6s ease-out, -webkit-transform .3s ease-out;
    transition: opacity .6s ease-out, transform .3s ease-out;
    transition: opacity .6s ease-out, transform .3s ease-out, -webkit-transform .3s ease-out;
}

// main.js 注册自定义指令
import * as directives from './directives'

Object.keys(directives).forEach(key => {
  Vue.directive(key, (directives as { [key: string ]: DirectiveOptions })[key])
})

指令可以接收两个参数

• color：波纹颜色
• type： 扩散位置，center表示从元素中心开始往四周扩散。hit为从点击位置开始扩散

<el-button type="primary" v-waves>查 询</el-button>
<el-button type="primary" v-waves="{color:'rgba(0,0,0,.3)'}">查 询</el-button>
<el-button type="primary" v-waves="{type:'hit'}">查 询</el-button>