修改demo

entry/src/main/ets/pages/DownSamplePage.ets

@@ -126,6 +126,8 @@ struct DownSamplePage {
       desiredPixelFormat: 3,
     }
     let imageInfo = await imageSource.getImageInfo()
+
+    if (this.imageKnifeOption.downsampleOf !== DownsampleStrategy.NONE){
       let reqSize =
         new Downsampler().calculateScaling(typeValue, imageInfo.size.width, imageInfo.size.height, 300,
           300, this.imageKnifeOption.downsampleOf)
@@ -136,6 +138,8 @@ struct DownSamplePage {
           height: reqSize.height
         }
       }
+    }
+
     // 创建pixelMap
     imageSource.createPixelMap(decodingOptions).then((pixelMap: image.PixelMap) => {
       this.afterSampling = pixelMap.getPixelBytesNumber()

library/src/main/ets/downsampling/DownsampleUtils.ets

@@ -28,7 +28,7 @@ export enum SampleSizeRounding {
   //（质量优先）
   QUALITY
 }
-
+//找出给定整数 i 中最高位的1（即最左边的1）所代表的值
 export function highestOneBit(i: number): number {
   i |= (i >> 1);
   i |= (i >> 2);