降采样适配3.x

Signed-off-by: tsm <2418639820@qq.com>

library/src/main/ets/downsampling/DownsampleStartegy.ets

@@ -14,13 +14,11 @@
  */
 import { BaseDownsampling } from './BaseDownsampling';
 import { highestOneBit,SampleSizeRounding } from './downsampleUtils';
-//FitCenter类实现DownsampleStartegy
 @Sendable
 export class FitCenter implements BaseDownsampling {
   getName() {
     return "FitCenter"
   }
-
   //实现 getScaleFactor 方法
   getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,autoResize?:boolean): number {
     const IS_BITMAP_FACTORY_SCALING_SUPPORTED = autoResize; //这里需要根据实际情况设置这个值
@@ -43,22 +41,16 @@ export class FitCenter implements BaseDownsampling {
     if (!IS_BITMAP_FACTORY_SCALING_SUPPORTED) {
       return 0;
     } else {
-      // TODO: 这个逻辑可能不正确，但是如果不这样做，我们可能会跳过一个采样尺寸，因为 QUALITY 更喜欢宽度和高度缩放因子中比较小的那个
-      //  MEMORY 折中方案,他让我们更喜欢两者中较大的那个
         return SampleSizeRounding.MEMORY;
     }
 
   }
 }
-
-//None 类实现 DownsampleStrategy 接口
 @Sendable
 export class None implements BaseDownsampling{
   getName(): string{
     return "DownsampleNone"
   }
-
-  //实现 getScaleFactor 方法
   public getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
     //不进行任何下采样，缩放因子为 1
     return 1;
@@ -66,7 +58,6 @@ export class None implements BaseDownsampling{
 
   //实现 getSampleSizeRounding 方法
   public getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): SampleSizeRounding {
-    //总是返回 QUALITY
     return SampleSizeRounding.QUALITY
 
   }
@@ -81,7 +72,6 @@ export class CenterOutside implements BaseDownsampling {
     return "CenterOutside"
   }
 
-  //实现 getScaleFactor 方法
   getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
     const widthPercentage = requestedWidth / sourceWidth;
     const heightPercentage = requestedHeight / sourceHeight;
@@ -89,7 +79,6 @@ export class CenterOutside implements BaseDownsampling {
     return Math.max(widthPercentage, heightPercentage);
   }
 
-  //实现 getSampleSizeRounding 方法
   getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): SampleSizeRounding {
     //根据 CenterOutside 的逻辑，总是返回 QUALITY
     return SampleSizeRounding.QUALITY;
@@ -99,11 +88,6 @@ export class CenterOutside implements BaseDownsampling {
 /*请求尺寸大于实际尺寸不进行放大,按照原图展示*/
 @Sendable
 export class Atleast implements BaseDownsampling {
-  //构造函数
-  constructor(){
-    //TypeScript 默认构造函数不需要特殊标记
-  }
-
   getName() {
     return "AtLeast"
   }
@@ -115,7 +99,6 @@ export class Atleast implements BaseDownsampling {
     //根据最小整数因子计算缩放因子
     return minIntegerFactor === 0 ? 1 : 1 / highestOneBit(minIntegerFactor);
   }
-  //实现 getSampleSizeRounding 方法
   public getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): SampleSizeRounding {
     //总是返回 QUALITY
     return SampleSizeRounding.QUALITY
@@ -134,24 +117,15 @@ export class AtMost implements BaseDownsampling {
     const maxIntegerFactor = Math.ceil(Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth));
     let lesserOrEqualSampleSize = Math.max(1, highestOneBit(maxIntegerFactor));
     let greaterOrEqualSampleSize = lesserOrEqualSampleSize
-    // if (lesserOrEqualSampleSize < maxIntegerFactor) {
+    if (lesserOrEqualSampleSize < maxIntegerFactor) {
-    //   let greaterOrEqualSampleSize = lesserOrEqualSampleSize <<= 1; // lest shift by 1
+      greaterOrEqualSampleSize = lesserOrEqualSampleSize <<= 1;
-    // }
+    }
     greaterOrEqualSampleSize = lesserOrEqualSampleSize << (lesserOrEqualSampleSize < maxIntegerFactor ? 1 : 0)
     //返回缩放因子
     return 1 / greaterOrEqualSampleSize
   }
 
-  highestOneBit(i: number): number {
-    i |= (i >> 1);
-    i |= (i >> 2);
-    i |= (i >> 4);
-    i |= (i >> 8);
-    i |= (i >> 16);
-    return i - (i >>> 1);
-  }
 
-  //实现 getSampleSizeRounding 方法
   getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestHeight: number): SampleSizeRounding {
     //根据 AtMost 的逻辑，总是返回 MEMORY
     return SampleSizeRounding.MEMORY
@@ -166,18 +140,16 @@ export class CenterInside implements BaseDownsampling {
     return "CenterInside"
   }
 
-  //实现 getScaleFactor 方法
   getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,autoResize?:boolean): number {
     //获取 FIT_CENTER 的缩放因子
     const fitCenterScaleFactor : ESObject = this.getScale(sourceWidth,sourceHeight,requestedWidth,requestedHeight,autoResize);
-    //实现 getScaleFactor 方法
     //返回不超过 1 的缩放因子，即尽量缩小图像以适应目标尺寸，但不会放大
     return Math.min(1,fitCenterScaleFactor);
 
   }
 
   getScale(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,autoResize?:boolean): number {
-    const IS_BITMAP_FACTORY_SCALING_SUPPORTED = autoResize; //这里需要根据实际情况设置这个值
+    const IS_BITMAP_FACTORY_SCALING_SUPPORTED = autoResize;
     if (IS_BITMAP_FACTORY_SCALING_SUPPORTED) {
       const widthPercentage = requestedWidth / sourceWidth
       const heightPercentage = requestedHeight / sourceHeight
@@ -190,9 +162,6 @@ export class CenterInside implements BaseDownsampling {
 
   }
 }
-
-
-  //实现 getSampleSizeRounding 方法
   getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,autoResize?:boolean): SampleSizeRounding {
   //如果缩放因子为 1，表示没有缩放，优先选择质量
     if (this.getScaleFactor(sourceWidth,sourceHeight,requestedWidth,requestedHeight,autoResize) === 1) {
@@ -201,27 +170,12 @@ export class CenterInside implements BaseDownsampling {
     //否则，使用 FIL_CENTER 的 SampleSizeRounding 值
     return this.getSampleSize(sourceWidth,sourceHeight,requestedWidth,requestedHeight);
     }
-
-  highestOneBit(i: number): number {
-    i |= (i >> 1);
-    i |= (i >> 2);
-    i |= (i >> 4);
-    i |= (i >> 8);
-    i |= (i >> 16);
-    return i - (i >>> 1);
-  }
-
-  //实现 getSampleSizeRounding 方法
   getSampleSize(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,autoResize?:boolean): SampleSizeRounding {
-    const IS_BITMAP_FACTORY_SCALING_SUPPORTED = autoResize; //这里需要根据实际情况设置这个值
+    const IS_BITMAP_FACTORY_SCALING_SUPPORTED = autoResize;
 
     if (IS_BITMAP_FACTORY_SCALING_SUPPORTED) {
       return 0;
     } else {
-      //   TODO: 这个逻辑可能不正确，但是如果不这样做，我们可能会跳过一个采样尺寸，因为 QUALITY 更喜欢宽度和高度缩放因子中比较小的那个
-      //    MEMORY 折中方案,他让我们更喜欢两者中较大的那个
-      //
-      // }
       return SampleSizeRounding.MEMORY;
     }
   }