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

Signed-off-by: 田双明 <tianshuangming@h-partners.com>
2024-10-09 08:39:28 +00:00 · 2024-10-09 08:39:28 +00:00 · 6e708e1c17
parent f80dd101d0
commit 6e708e1c17
1 changed files with 79 additions and 54 deletions
--- a/library/src/main/ets/downsampling/DownsampleStartegy.ets
+++ b/library/src/main/ets/downsampling/DownsampleStartegy.ets
@ -13,28 +13,34 @@
 * limitations under the License.
 */
 import { BaseDownsampling } from './BaseDownsampling';
-import { highestOneBit, SampleSizeRounding } from './DownsampleUtils';
+import { getScale, highestOneBit, round, SampleSizeRounding } from './DownsampleUtils';

 export class FitCenter implements BaseDownsampling {
  getName() {
    return "FitCenter"
  }

-  getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy |undefined
+  getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,
+    downsampType: DownsampleStrategy
  ): number {
-    if (downsampType===DownsampleStrategy.FIT_CENTER_MEMORY) {
-      const widthPercentage = requestedWidth / sourceWidth
-      const heightPercentage = requestedHeight / sourceHeight
-      return Math.min(widthPercentage, heightPercentage)
-    } else {
-      const maxIntegerFactor = Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth);
-      const a = maxIntegerFactor === 0 ? 1 : 1 / highestOneBit(maxIntegerFactor)
-      return a;
+    //重新计算宽高比;
+    let outSize: Size = {
+      width: round(getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType) * sourceWidth),
+      height:round(getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType) * sourceHeight)
    }
+    let scaleFactor = this.getSampleSizeType(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType)===
+    SampleSizeRounding.QUALITY? Math.max(1, highestOneBit(Math.max(sourceWidth / outSize.width, sourceHeight / outSize.height))) :
+    Math.max(1, highestOneBit(Math.min(sourceWidth / outSize.width, sourceHeight / outSize.height)))//将整型的缩放因子转换为2的次幂采样大小
+
+    if (this.getSampleSizeType(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType)===
+    SampleSizeRounding.MEMORY && (scaleFactor < (1 / getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType)))) {
+      scaleFactor = scaleFactor << 1;
+    }
+    return scaleFactor
  }

-  //实现 getSampleSizeRounding 方法
-  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy|undefined
+  getSampleSizeType(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,
+    downsampType: DownsampleStrategy
  ): number {
    if (downsampType === DownsampleStrategy.FIT_CENTER_QUALITY) {
      return SampleSizeRounding.QUALITY;
@ -52,15 +58,19 @@ export class None implements BaseDownsampling {

  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;
+    let outSize: Size = {
+      width: round(sourceWidth),
+      height:round(sourceHeight)
+    }
+    let scaleFactor =
+      Math.max(1, highestOneBit(Math.max(sourceWidth / outSize.width, sourceHeight / outSize.height)))
+    return scaleFactor
  }

-  //实现 getSampleSizeRounding 方法
-  public getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number,
+  //实现 getSampleSizeType 方法
+  public getSampleSizeType(sourceWidth: number, sourceHeight: number, requestedWidth: number,
    requestedHeight: number): SampleSizeRounding {
    return SampleSizeRounding.QUALITY
-
  }
 }

@ -77,10 +87,16 @@ export class CenterOutside implements BaseDownsampling {
    const widthPercentage = requestedWidth / sourceWidth;
    const heightPercentage = requestedHeight / sourceHeight;
    //返回宽度和高度比例中最大的值
-    return Math.max(widthPercentage, heightPercentage);
+    let outSize: Size = {
+      width: round(Math.max(widthPercentage, heightPercentage) * sourceWidth),
+      height:round(Math.max(widthPercentage, heightPercentage) * sourceHeight)
+    }
+    let scaleFactor = Math.max(1, highestOneBit(Math.max(sourceWidth / outSize.width, sourceHeight / outSize.height)))
+
+    return scaleFactor
  }

-  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number,
+  getSampleSizeType(sourceWidth: number, sourceHeight: number, requestedWidth: number,
    requestedHeight: number): SampleSizeRounding {
    return SampleSizeRounding.QUALITY;
  }
@ -93,7 +109,7 @@ export class AtMost implements BaseDownsampling {
    return "AtMost"
  }

-  //实现 getScaleFactor 方法
+
  getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
    const maxIntegerFactor = Math.ceil(Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth));
    let lesserOrEqualSampleSize = Math.max(1, highestOneBit(maxIntegerFactor));
@ -103,11 +119,19 @@ export class AtMost implements BaseDownsampling {
    }
    greaterOrEqualSampleSize = lesserOrEqualSampleSize << (lesserOrEqualSampleSize < maxIntegerFactor ? 1 : 0)
    //返回缩放因子
-    return 1 / greaterOrEqualSampleSize
+    let outSize: Size = {
+      width: round((1 / greaterOrEqualSampleSize) * sourceWidth),
+      height:round((1 / greaterOrEqualSampleSize) * sourceHeight)
+    }
+    let scaleFactor = Math.max(1, highestOneBit(Math.min(sourceWidth / outSize.width, sourceHeight / outSize.height)))
+    if ((scaleFactor < greaterOrEqualSampleSize)) {
+      scaleFactor = scaleFactor << 1;
+    }
+    return scaleFactor
  }


-  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number,
+  getSampleSizeType(sourceWidth: number, sourceHeight: number, requestedWidth: number,
    requestHeight: number): SampleSizeRounding {
    //根据 AtMost 的逻辑，总是返回 MEMORY
    return SampleSizeRounding.MEMORY
@ -120,41 +144,42 @@ export class CenterInside implements BaseDownsampling {
  getName() {
    return "CenterInside"
  }
-
-  getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy|undefined
+  getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,
+    downsampType: DownsampleStrategy
  ): number {
-    //获取 FIT_CENTER 的缩放因子
-    const fitCenterScaleFactor: ESObject =
-      this.getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType);
-    //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);
+
+    let outSize: Size = {
+      width: round(Math.min(1, getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType)) * sourceWidth),
+      height:round(Math.min(1, getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType)) * sourceHeight)
+    }
+    let scaleFactor = this.getSampleSizeType(sourceWidth, sourceHeight, requestedWidth, requestedHeight,
+    downsampType) == SampleSizeRounding.QUALITY ?
+    Math.max(sourceWidth / outSize.width, sourceHeight / outSize.height) :
+      Math.min(sourceWidth / outSize.width, sourceHeight / outSize.height) //重新计算宽高比
+
+    scaleFactor = Math.max(1, highestOneBit(scaleFactor))//将整型的缩放因子转换为2的次幂采样大小
+
+    if (this.getSampleSizeType(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType)
+      == SampleSizeRounding.MEMORY  && (scaleFactor < (1 / Math.min(1, getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType))))) {
+      scaleFactor = scaleFactor << 1;
+    }
+    return scaleFactor

  }

-  getScale(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy|undefined
-  ): number {
-    if (downsampType===DownsampleStrategy.FIT_CENTER_MEMORY) {
-      const widthPercentage = requestedWidth / sourceWidth
-      const heightPercentage = requestedHeight / sourceHeight
-      return Math.min(widthPercentage, heightPercentage)
-    } else {
-      const maxIntegerFactor = Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth);
-      const a = maxIntegerFactor === 0 ? 1 : 1 / highestOneBit(maxIntegerFactor)
-      return a;
-    }
-  }
-
-  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy|undefined
+  getSampleSizeType(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,
+    downsampType: DownsampleStrategy
  ): 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, downsampType) === 1) {
+    if (Math.min(1, getScale(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType)) === 1) {
      return SampleSizeRounding.QUALITY
    }
    //否则，使用 FIL_CENTER 的 SampleSizeRounding 值
    return this.getSampleSize(sourceWidth, sourceHeight, requestedWidth, requestedHeight, downsampType);
  }

-  getSampleSize(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy|undefined
+  getSampleSize(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,
+    downsampType: DownsampleStrategy
  ): SampleSizeRounding {
    if (downsampType === DownsampleStrategy.CENTER_INSIDE_MEMORY) {
      return SampleSizeRounding.MEMORY;