HarmonyOS 拍照后的图片转base64

示例如下：

let packOpts: image.PackingOption = { format: "image/jpeg", quality: 98 };
let imagePackerApi = image.createImagePacker();


const context: Context = getContext(this);
const resourceMgr = context.resourceManager;
let imageBuffer = await resourceMgr.getMediaContent($r('app.media.ic_low'));
const imageSource: image.ImageSource = image.createImageSource(imageBuffer.buffer);
let decodingOptions: image.DecodingOptions = {
  editable: true,
  desiredPixelFormat: 3,
  rotate: 90
}
// 创建pixelMap并进行简单的旋转和缩放

imageSource.createPixelMap(decodingOptions).then((pixelMap: PixelMap) => {

  this.pixelMap = pixelMap
  // pixelmap 转base64 先要有一个packing的过程
  imagePackerApi.packing(pixelMap, packOpts).then((data: ArrayBuffer) => {
    let base64Str = buffer.from(data).toString('base64')
    let resultBase64Str = "data:image/png;base64," + base64Str
    this.resultBase64Str = resultBase64Str
  }).catch((error: BusinessError) => {
    console.error('Failed to pack the image. And the error is: ' + error);
  })
  pixelMap.release();
})

//重点提示： pixelmap转base64 不能直接转，先要加一个packing的过程，下面的方法是一个错误的实例，转出来的base64字符串不对。
let pixelMap = await imageSource.createPixelMap(opts);
console.log("pixelMap.getPixelBytesNumber():" + pixelMap.getPixelBytesNumber())
let arrayBuffer = new ArrayBuffer(pixelMap.getPixelBytesNumber());
pixelMap.readPixelsToBuffer(arrayBuffer)
console.log("arrayBuffer" + arrayBuffer)
let base64Str = buffer.from(arrayBuffer).toString(Constants.BASE_64);
let resultBase64Str = "data:image/png;base64," + base64Str
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.