新闻发布大于1M压缩图片

src/views/modules/news/news-publish.vue

@@ -200,7 +200,7 @@ export default {
   },
   watch: {
     'dataForm.allDeptIdsShow': function (val) {
-        console.log(this.dataForm.allDeptIdsShow);
+      console.log(this.dataForm.allDeptIdsShow)
     }
   },
   created () {
@@ -441,6 +441,66 @@ export default {
     },
     beforeAvatarUpload (file) {
       this.loading = true
+      var that = this
+      return new Promise((resolve, reject) => {
+        const isJPG = file.type === 'image/jpeg'
+        const isPNG = file.type === 'image/png'
+        const isLt1M = file.size / 1024 / 1024 < 1
+        let bool = false
+        // 判断是否符合格式要求
+        if (isJPG || isPNG) {
+          bool = true
+        } else {
+          that.$message.error('上传文件必须是jpg、png格式!')
+          return false
+        }
+        // 如果格式符合要求，但是size过大，对图片进行处理
+        if (bool && !isLt1M) {
+          let image = new Image()
+          let resultBlob = ''
+          image.src = URL.createObjectURL(file)
+          image.onload = () => {
+            resultBlob = that.compressUpload(image)
+            resolve(resultBlob)
+          }
+        } else if (bool && isLt1M) {
+          resolve(file)
+        }
+      })
+    },
+    compressUpload (image) {
+      // 创建画布元素
+      let canvas = document.createElement('canvas')
+      let ctx = canvas.getContext('2d')
+      let { width } = image
+      let { height } = image
+      canvas.width = width
+      canvas.height = height
+      ctx.fillRect(0, 0, canvas.width, canvas.height)
+      ctx.drawImage(image, 0, 0, width, height)
+      // 等比压缩
+      let compressData = canvas.toDataURL('image/jpeg', 0.8)
+      // base64转Blob
+      let blobImg = this.dataURItoBlob(compressData)
+      return blobImg
+    },
+    dataURItoBlob (data) {
+      let byteString
+      if (data.split(',')[0].indexOf('base64') >= 0) {
+        // 转二进制
+        byteString = atob(data.split(',')[1])
+      } else {
+        byteString = unescape(data.split(',')[1])
+      }
+      let mimeString = data
+        .split(',')[0]
+        .split(':')[1]
+        .split('')[0]
+      let ia = new Uint8Array(byteString.length)
+      for (let i = 0; i < byteString.length; i += 1) {
+        ia[i] = byteString.charCodeAt(i)
+      }
+      return new Blob([ia], { type: mimeString })
     },
     handelError () {
       this.loading = false