URL to Blob
1 public urlToBlob(url) { 2 const self = this; 3 const image = new Image(); 4 image.crossOrigin = ''; 5 image.src = url; 6 image.onload = function () { 7 // 图片的绝对路径地址 转换成base64编码 如下代码： 8 const canvas = document.createElement('canvas'); 9 canvas.width = image.width; 10 canvas.height = image.height; 11 const ctx = canvas.getContext('2d'); 12 ctx.drawImage(image, 0, 0, image.width, image.height); 13 // canvas.toBlob((res) => { 14 // console.log(res); 15 // self.communityFormData.delete('image'); 16 // self.communityFormData.append('image', res); 17 // console.log(self.communityFormData.get('image')); 18 // }); 19 const ext = image.src.substring(image.src.lastIndexOf('.') + 1).toLowerCase(); 20 const dataURL = canvas.toDataURL('image/' + ext); 21 const type = 'image/' + ext; 22 console.log(dataURL); 23 const bytes = window.atob(dataURL.split(',')[1]); // 去掉url的头，并转换为byte 24 console.log(bytes); 25 // 处理异常,将ascii码小于0的转换为大于0 26 const ab = new ArrayBuffer(bytes.length); 27 console.log(ab); 28 const ia = new Uint8Array(ab); 29 console.log(ia); 30 for (let i = 0; i < bytes.length; i++) { 31 ia[i] = bytes.charCodeAt(i); 32 } 33 console.log(ia); 34 const tempBlob = new Blob([ia], { type: type }); 35 self.communityFormData.delete('image'); 36 self.communityFormData.append('image', tempBlob); 37 console.log(tempBlob); 38 }; 39 }
将服务端传过来的图片绝对地址转成 Blob 类型返回给 服务端
