diff --git a/library/src/main/ets/components/imageknife/Downsampling/Downsampler.ets b/library/src/main/ets/components/imageknife/Downsampling/Downsampler.ets
index 4624e6a..ab9eb3f 100644
--- a/library/src/main/ets/components/imageknife/Downsampling/Downsampler.ets
+++ b/library/src/main/ets/components/imageknife/Downsampling/Downsampler.ets
@@ -36,13 +36,13 @@ export class Downsampler {
       orientedSourceHeight = sourceWidth;
     }
     /*安卓的模式*/
-    let exactScaleFactor: number = new FitCenter().getScaleFactor(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+    let exactScaleFactor: number = FitCenter.getScaleFactor(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
     if (exactScaleFactor <= 0) {
       throw new Error("Cannot	round	with exactScaleFactor");
     }
     console.log('exactScaleFactor', exactScaleFactor)
     /*安卓的模式*/
-    let rounding: SampleSizeRounding = new FitCenter().getSampleSizeRounding(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+    let rounding: SampleSizeRounding = CenterOutside.getSampleSizeRounding(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
     if (rounding == null) {
       throw new Error("Cannot round with null rounding");
     }
@@ -53,6 +53,7 @@ export class Downsampler {
     let scaleFactor = rounding == SampleSizeRounding.MEMORY ? Math.max(widthScaleFactor, heightScaleFactor) : Math.min(widthScaleFactor, heightScaleFactor)
     // 将整型的缩放因子转换为2的次幂采样大小
     let powerOfTwoSampleSize: number = 0;
+    powerOfTwoSampleSize = Math.max(1,this.highestOneBit(scaleFactor))
     if (rounding == SampleSizeRounding.MEMORY && powerOfTwoSampleSize < (1 / exactScaleFactor)) {
       powerOfTwoSampleSize = powerOfTwoSampleSize << 1;
     }