Vue自定义指令结合阿里云OSS优化图片的实现方法

Vue.directive('img-condense', {
 bind: (el, binding, vnode) => {
  let src = el.getAttribute('src')
  let newSrc = pressImg(src, el)
  el.setAttribute('src', newSrc)
 }
})

let pressImg = (imgUrl, el) => {
 // 获取显示设备 pixelRatio
 let pixelRatio = window.devicePixelRatio
 let elWidth = elStyle.width  pixelRatio
 let elHeight = elStyle.height  pixelRatio
 let resize = '/resize'
 if (elWidth) {
  resize += `,w_${elWidth}`
 }
 if (elHeight) {
  resize += `,h_${elHeight}`
 }
})

let canUseWebp = document.createElement('canvas').toDataURL('image/webp').indexOf('data:image/webp') == 0
let webp = ''
if (canUseWebp) {
 webp = '/format,webp'
}

let ossParam?x-oss-process=image${resize}/auto-orient,1/quality,Q_80/bright,-1${webp}

<img v-img-condense alt="Vue logo" src="../assets/logo.png">
Vue.directive('img-condense', {
 bind: (el, binding, vnode) => {
  let src = el.getAttribute('src')
  let newSrc = pressImg(src, el)
  el.setAttribute('src', newSrc)
 }
})
let pressImg = (imgUrl, el) => {
 // 如果不是oss 或者已经压缩过的图片直接返回
 if (imgUrl.includes('aliyuncs.') || imgUrl.indexOf('blob') === 0 || imgUrl.includes('x-oss-process=')){
  return imgUrl 
 }
 // 获取显示设备 pixelRatio
 let pixelRatio = window.devicePixelRatio
 let elWidth = el.width  pixelRatio
 let elHeight = el.height  pixelRatio
 let resize = '/resize'
 if (elWidth) {
  resize += `,w_${elWidth}`
 }
 if (elHeight) {
  resize += `,h_${elHeight}`
 }
 if (!elWidth && !elHeight) {
  resize = ''
 }
 // 判断webp
 let canUseWebp = document.createElement('canvas').toDataURL('image/webp').indexOf('data:image/webp') == 0
 let webp = ''
 if (canUseWebp) {
  webp = '/format,webp'
 }
 return `${imgUrl}?x-oss-process=image${resize}/auto-orient,1/quality,Q_80/bright,-1${webp}`
}