图片文件与PixelMap、ArrayBuffer如何互相转换？

// Copyright (c) 2024-2025 IsOneHeart SoulHarbor - PixelArtisan

import image from '@ohos.multimedia.image';
import { resourceManager } from '@kit.LocalizationKit';
import { BusinessError } from '@kit.BasicServicesKit';

export class GetPixelMap {
  private url: string;
  private resourceMgr: resourceManager.ResourceManager;

  constructor(url: string) {
    this.url = url;
    const context: Context = getContext();
    this.resourceMgr = context.resourceManager;
  }

  public async getImageSource(): Promise<image.PixelMap | null> {
    try {
      // 获取图片的ArrayBuffer
      const fileData: Uint8Array = await this.resourceMgr.getRawFileContent(this.url);
      console.log("成功获取图片的ArrayBuffer。");
      const buffer = fileData.buffer.slice(0);
      const imageSource: image.ImageSource = image.createImageSource(buffer);
      // 创建pixelMap
      const pixelMap: image.PixelMap = await imageSource.createPixelMap();
      console.info("成功创建pixelMap。");
      return pixelMap;
    } catch (err) {
      console.error(err);
      return null;
    }
  }
}

export function getNeoPixelMap(): Promise<ArrayBuffer> {
  return new Promise((resolve, reject) => {
    const context: Context = getContext();
    const resourceMgr: resourceManager.ResourceManager = context.resourceManager;
    resourceMgr.getRawFileContent('test.jpg').then((fileData: Uint8Array) => {
      console.log("Succeeded in getting RawFileContent");
      const imageSource: image.ImageSource = image.createImageSource(fileData.buffer);
      imageSource.createPixelMap().then((pixelMap: PixelMap) => {
        const length: number = pixelMap.getPixelBytesNumber();
        const readBuffer: ArrayBuffer = new ArrayBuffer(length);
        pixelMap.readPixelsToBuffer(readBuffer).then(() => {
          console.info('Succeeded in reading image pixel data.');
          resolve(readBuffer);
        }).catch((error: BusinessError) => {
          console.error(`Failed to read image pixel data. code is ${error.code}, message is${error.message}`);
          reject(error);
        });
      }).catch((error: BusinessError) => {
        console.error("Failed to createPixelMap");
        reject(error);
      });
    }).catch((error: BusinessError) => {
      console.error("Failed to get RawFileContent");
      reject(error);
    });
  });
}
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