feat: 绘画页面对接腾讯混元文生图

composables/useBlobUrlFromB64.ts

@@ -0,0 +1,20 @@
+export const useBlobUrlFromB64 = (dataurl: string): string => {
+  // data:image/jpeg;base64,/9j/...
+  const arr = dataurl.split(',')
+  if (arr.length < 2) {
+    throw new Error('dataurl is not a valid base64 image')
+  }
+  const mimeMatches = arr[0].match(/:(.*?);/)
+  if (mimeMatches === null) {
+    throw new Error('dataurl is not a valid base64 image')
+  }
+  const mime = mimeMatches[1]  //image/png
+  const b64data = atob(arr[1])
+  let length = b64data.length
+  const u8arr = new Uint8Array(length)
+  while (length--) {
+    u8arr[length] = b64data.charCodeAt(length)
+  }
+  const blob = new Blob([u8arr], {type: mime})
+  return URL.createObjectURL(blob)
+}