HarmonyOS 鸿蒙Next图片处理合成相关

可以通过画布的getPixelMap方法（以当前canvas指定区域内的像素创建PixelMap对象）：

[@Entry](/user/Entry)
[@Component](/user/Component)
struct GetImageData {
 private settings: RenderingContextSettings = new RenderingContextSettings(true)
 private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
 private offCanvas: OffscreenCanvas = new OffscreenCanvas(600, 600)
 private img:ImageBitmap = new ImageBitmap("/common/images/666.png")
 private img2:ImageBitmap = new ImageBitmap("/common/images/90.jpg");
 [@State](/user/State) ima:PixelMap|undefined=undefined;

 build() {
   Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
     Canvas(this.context)
       .width(‘100%’)
     .height(‘100%’)
     .backgroundColor(’#F5DC62’)
     .onReady(() =>{
       let offContext = this.offCanvas.getContext(“2d”, this.settings)
       // 使用drawImage接口将图片画在（0，0）为起点，宽高130的区域
       offContext.drawImage(this.img,0,0,100,100);
       offContext.drawImage(this.img2,40,40,20,20);
       // 使用getImageData接口，获得canvas组件区域中，（50，50）为起点，宽高130范围内的绘制内容
       //let imagedata = offContext.getImageData(50,50,130,130);
       let imagedata = offContext.getImageData(50,50,130,130);
       this.ima=offContext.getPixelMap(0,0,100,100);
       // 使用putImageData接口将得到的ImageData画在起点为（150， 150）的区域中
       // offContext.putImageData(imagedata,150,150);
       // 将离屏绘制的内容画到canvas组件上
       let image = this.offCanvas.transferToImageBitmap();
       this.context.transferFromImageBitmap(image);
     })
     Image(this.ima)
       .width(100).height(100)

   }
   .width(‘100%’)
   .height(‘100%’)
 }
}