!379 imageKnife降采样

Merge pull request !379 from 田双明/master

CHANGELOG.md

@@ -3,6 +3,7 @@
 - 修复加载错误图后未去请求排队队列中的请求
 - 子线程本地Resource参数类型转换成number
 - 修改使用hilog记录日志，默认打开debug级别的日志
+- 增加降采样
 
 ## 3.1.0-rc.2
 - 修复宽高不等svg图片显示有毛边

README.md

@@ -264,6 +264,17 @@ ImageKnifeAnimatorComponent({
         }),animatorOption:this.animatorOption
       }).width(300).height(300).backgroundColor(Color.Orange).margin({top:30})
 ```
+#### 11.图片降采样 示例
+```
+ImageKnifeComponent({
+        imageKnifeOption:new ImageKnifeOption({
+          loadSrc:$r("app.media.pngSample"),
+          placeholderSrc:$r('app.media.loading'),
+          errorholderSrc:$r('app.media.failed'),
+          downsampleOf: DownsampleStrategy.NONE
+        }),animatorOption:this.animatorOption
+      }).width(300).height(300)
+```
 ## 接口说明
 ### ImageKnife组件
 | 组件名称                        | 入参内容                            | 功能简介   |
@@ -306,7 +317,17 @@ ImageKnifeAnimatorComponent({
 | drawingColorFilter    | ColorFilter | drawing.ColorFilter                     | 图片变换（可选）        |
 | onComplete            | (event:EventImage | undefined) => voi                 | 颜色滤镜效果（可选）        |
 | onLoadListener        | onLoadStart: () => void、onLoadSuccess: (data: string | PixelMap | undefined) => void、onLoadFailed: (err: string) => void| 监听图片加载成功与失败     |
-
+| downsampleOf          | DownsampleStrategy                                    | 降采样(可选)                  |
+### 降采样类型
+| 类型                  | 相关描述              |
+|---------------------|-------------------|
+| NONE                | 不进行降采样            |
+| AT_MOST             | 请求尺寸大于实际尺寸不进行放大   |
+| FIT_CENTER_MEMORY          | 两边自适应内存优先             |
+| FIT_CENTER_QUALITY          | 两边自适应质量优先             |
+| CENTER_INSIDE_MEMORY       | 宽高缩放比最大的比例，进行缩放适配内存优先 |
+| CENTER_INSIDE_QUALITY       | 宽高缩放比最大的比例，进行缩放适配质量优先 |
+| CENTER_OUTSIDE      | 根据宽高的最小的比例，进行适配   |
 ### ImageKnife接口
 
 | 参数名称             | 入参内容                                                                                                  | 功能简介          |

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

@@ -0,0 +1,208 @@
+/*
+ * Copyright (C) 2024 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { DownsampleStrategy, ImageKnifeOption, } from '@ohos/imageknife';
+import { ImageKnifeComponent, BlurTransformation, } from '@ohos/libraryimageknife';
+import { image } from '@kit.ImageKit';
+import { BusinessError } from '@kit.BasicServicesKit';
+import { Downsampler } from '@ohos/imageknife/src/main/ets/downsampling/Downsampler';
+import { FileTypeUtil } from '@ohos/imageknife/src/main/ets/utils/FileTypeUtil';
+
+@Entry
+@ComponentV2
+struct DownSamplePage {
+  @Local imageKnifeOption: ImageKnifeOption = new ImageKnifeOption( {
+    loadSrc: $r('app.media.startIcon'),
+    placeholderSrc: $r("app.media.loading"),
+    errorholderSrc: $r("app.media.app_icon"),
+    objectFit: ImageFit.Contain
+  })
+  isBrightness: boolean = false
+  @Local beforeSampling: number = 0
+  @Local afterSampling: number = 0
+  @Local SamplingList: SamplingType[] = [
+    new SamplingType(0, "NONE"),
+    new SamplingType(1, "AT_MOST"),
+    new SamplingType(2, "FIT_CENTER_MEMORY"),
+    new SamplingType(4, "FIT_CENTER_QUALITY"),
+    new SamplingType(5, "CENTER_INSIDE_MEMORY"),
+    new SamplingType(6, "CENTER_INSIDE_QUALITY"),
+    new SamplingType(7, "CENTER_OUTSIDE"),
+  ]
+  @Local checked: boolean = false
+
+  updateImageKnifeOption(value: string) {
+    if (value === 'NONE') {
+      this.imageKnifeOption =new ImageKnifeOption( {
+        loadSrc: $r('app.media.jpgSample'),
+        placeholderSrc: $r("app.media.loading"),
+        errorholderSrc: $r("app.media.app_icon"),
+        objectFit: ImageFit.Contain,
+        downsampleOf: DownsampleStrategy.NONE
+      })
+      this.originalPixMap($r('app.media.jpgSample'))
+      this.afterSamplingFunc($r('app.media.jpgSample'))
+    } else if (value === 'AT_MOST') {
+      this.imageKnifeOption =new ImageKnifeOption( {
+        loadSrc: $r('app.media.svgSample'),
+        placeholderSrc: $r("app.media.loading"),
+        errorholderSrc: $r("app.media.app_icon"),
+        objectFit: ImageFit.Contain,
+        downsampleOf: DownsampleStrategy.AT_MOST
+      })
+      this.originalPixMap($r('app.media.svgSample'))
+      this.afterSamplingFunc($r('app.media.svgSample'))
+    } else if (value === 'FIT_CENTER_MEMORY') {
+      this.imageKnifeOption =new ImageKnifeOption( {
+        loadSrc: $r('app.media.pngSample'),
+        placeholderSrc: $r("app.media.loading"),
+        errorholderSrc: $r("app.media.app_icon"),
+        objectFit: ImageFit.Contain,
+        downsampleOf: DownsampleStrategy.FIT_CENTER_MEMORY
+      })
+      this.originalPixMap($r('app.media.pngSample'))
+      this.afterSamplingFunc($r('app.media.pngSample'))
+    }
+    else if (value ==='FIT_CENTER_QUALITY') {
+      this.imageKnifeOption =new ImageKnifeOption( {
+        loadSrc: $r('app.media.pngSample'),
+        placeholderSrc: $r("app.media.loading"),
+        errorholderSrc: $r("app.media.app_icon"),
+        objectFit: ImageFit.Contain,
+        downsampleOf: DownsampleStrategy.FIT_CENTER_QUALITY
+      })
+      this.originalPixMap($r('app.media.pngSample'))
+      this.afterSamplingFunc($r('app.media.pngSample'))
+    }
+    else if (value === 'CENTER_INSIDE_MEMORY') {
+      this.imageKnifeOption = new ImageKnifeOption({
+        loadSrc: $r('app.media.jpgSample1'),
+        placeholderSrc: $r("app.media.loading"),
+        errorholderSrc: $r("app.media.app_icon"),
+        objectFit: ImageFit.Contain,
+        downsampleOf: DownsampleStrategy.CENTER_INSIDE_MEMORY
+      })
+      this.originalPixMap($r('app.media.jpgSample1'))
+      this.afterSamplingFunc($r('app.media.jpgSample1'))
+    }    else if (value === 'CENTER_INSIDE_QUALITY') {
+      this.imageKnifeOption = new ImageKnifeOption({
+        loadSrc: $r('app.media.jpgSample1'),
+        placeholderSrc: $r("app.media.loading"),
+        errorholderSrc: $r("app.media.app_icon"),
+        objectFit: ImageFit.Contain,
+        downsampleOf: DownsampleStrategy.CENTER_INSIDE_QUALITY
+      })
+      this.originalPixMap($r('app.media.jpgSample1'))
+      this.afterSamplingFunc($r('app.media.jpgSample1'))
+    }
+    else {
+      this.imageKnifeOption = new ImageKnifeOption({
+        loadSrc: $r('app.media.jpgSample2'),
+        placeholderSrc: $r("app.media.loading"),
+        errorholderSrc: $r("app.media.app_icon"),
+        objectFit: ImageFit.Contain,
+        downsampleOf: DownsampleStrategy.CENTER_OUTSIDE
+      })
+      this.originalPixMap($r('app.media.jpgSample2'))
+      this.afterSamplingFunc($r('app.media.jpgSample2'))
+    }
+  }
+
+  async afterSamplingFunc(imgs: Resource) {
+    let img: Uint8Array = await getContext(this).resourceManager.getMediaContent(imgs);
+    let imageSource: image.ImageSource = image.createImageSource(img.buffer.slice(0));
+    let fileTypeUtil = new FileTypeUtil();
+    let typeValue = fileTypeUtil.getFileType(img.buffer.slice(0));
+    let decodingOptions: image.DecodingOptions = {
+      editable: true,
+      desiredPixelFormat: 3,
+    }
+    let imageInfo = await imageSource.getImageInfo()
+    let reqSize =
+      new Downsampler().calculateScaling(typeValue, imageInfo.size.width, imageInfo.size.height, 300,
+        300, this.imageKnifeOption.downsampleOf)
+    decodingOptions = {
+      editable: true,
+      desiredSize: {
+        width: reqSize.targetWidth,
+        height: reqSize.targetHeight
+      }
+    }
+    // 创建pixelMap
+    imageSource.createPixelMap(decodingOptions).then((pixelMap: image.PixelMap) => {
+      this.afterSampling = pixelMap.getPixelBytesNumber()
+    }).catch((err: BusinessError) => {
+      console.error("Failed to create PixelMap")
+    });
+  }
+
+  async originalPixMap(imgs: Resource,) {
+    let img: Uint8Array = await getContext(this).resourceManager.getMediaContent(imgs);
+    let imageSource: image.ImageSource = image.createImageSource(img.buffer.slice(0));
+    let decodingOptions: image.DecodingOptions = {
+      editable: true,
+      desiredPixelFormat: 3,
+    }
+    // 创建pixelMap
+    imageSource.createPixelMap(decodingOptions).then((pixelMap: image.PixelMap) => {
+      this.beforeSampling = pixelMap.getPixelBytesNumber()
+    }).catch((err: BusinessError) => {
+      console.error("Failed to create PixelMap")
+    });
+  }
+
+  build() {
+    Scroll() {
+      Column() {
+        ForEach(this.SamplingList, (item: SamplingType, index) => {
+          Flex({ justifyContent: FlexAlign.Center, alignItems: ItemAlign.Center }) {
+            Radio({ value: item.value + 'radio', group: 'radioGroup' })
+              .height(50)
+              .width(50)
+              .checked(this.checked)
+              .onClick(() => {
+                this.updateImageKnifeOption(item.value)
+              })
+            Text("降采样规格：" + item.value).fontSize(20)
+          }
+        }, (item: SamplingType) => JSON.stringify(item))
+        Column() {
+          Text(`未降采样大小：${this.beforeSampling}`).fontSize(20)
+          Text(`降采样后大小：${this.afterSampling}`).fontSize(20)
+        }
+
+        ImageKnifeComponent({
+          imageKnifeOption: this.imageKnifeOption
+        })
+          .height(300)
+          .width(300)
+          .borderWidth(1)
+          .borderColor(Color.Pink)
+      }
+
+    }
+    .height('100%')
+    .width('100%')
+  }
+}
+
+class SamplingType {
+  key: number
+  value: string
+
+  constructor(key: number, value: string) {
+    this.key = key
+    this.value = value
+  }
+}

entry/src/main/ets/pages/Index.ets

@@ -47,6 +47,11 @@ struct Index {
 
           });
         })
+        Button("降采样").margin({top:10}).onClick(() => {
+          router.push({
+            uri: 'pages/DownSamplePage',
+          });
+        })
         Button("单个图片使用").margin({top:10}).onClick(()=>{
           router.push({
             uri: 'pages/SingleImage',

entry/src/main/resources/base/profile/main_pages.json

@@ -23,6 +23,7 @@
     "pages/ImageAnimatorPage",
     "pages/TestSetCustomImagePage",
     "pages/TestErrorHolderPage",
-    "pages/TestTaskResourcePage"
+    "pages/TestTaskResourcePage",
+    "pages/DownSamplePage"
   ]
 }

entry/src/ohosTest/ets/test/List.test.ets

@@ -18,6 +18,7 @@ import ImageKnifeOptionTest from './ImageKnifeOption.test';
 import MemoryLruCacheTest from './MemoryLruCache.test';
 import ImageKnifeTest from './ImageKnife.test';
 import Transform from './transform.test';
+import SamplingTest from './SamplingTest.test';
 
 export default function testsuite() {
   MemoryLruCacheTest();
@@ -26,4 +27,5 @@ export default function testsuite() {
   ImageKnifeOptionTest();
   ImageKnifeTest();
   Transform();
+  SamplingTest()
 }

entry/src/ohosTest/ets/test/SamplingTest.test.ets

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2024 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { describe, beforeAll, beforeEach, afterEach, afterAll, it, expect } from '@ohos/hypium'
+import { image } from '@kit.ImageKit'
+import { BusinessError } from '@kit.BasicServicesKit'
+import { calculateScaleType, Downsampler } from '@ohos/imageknife/src/main/ets/downsampling/Downsampler'
+import { DownsampleStrategy } from '@ohos/imageknife'
+
+export default function SamplingTest() {
+  describe('SamplingTest', () => {
+    // Defines a test suite. Two parameters are supported: test suite name and test suite function.
+    beforeAll(() => {
+      // Presets an action, which is performed only once before all test cases of the test suite start.
+      // This API supports only one parameter: preset action function.
+    })
+    beforeEach(() => {
+      // Presets an action, which is performed before each unit test case starts.
+      // The number of execution times is the same as the number of test cases defined by **it**.
+      // This API supports only one parameter: preset action function.
+    })
+    afterEach(() => {
+      // Presets a clear action, which is performed after each unit test case ends.
+      // The number of execution times is the same as the number of test cases defined by **it**.
+      // This API supports only one parameter: clear action function.
+    })
+    afterAll(() => {
+      // Presets a clear action, which is performed after all test cases of the test suite end.
+      // This API supports only one parameter: clear action function.
+    })
+    it('NONE', 0, () => {
+      let reqSize: calculateScaleType =
+        new Downsampler().calculateScaling('jpg', 1024, 1024, 200,
+          200, DownsampleStrategy.NONE, false)
+      let req = (reqSize.targetWidth == 1024 && reqSize.targetHeight == 1024)
+      expect(req).assertEqual(true);
+    })
+    it('AT_MOST', 1, () => {
+      let reqSize: calculateScaleType =
+        new Downsampler().calculateScaling('jpg', 1024, 1024, 200,
+          200, DownsampleStrategy.AT_MOST, false)
+      let req = (reqSize.targetWidth < 1024 && reqSize.targetHeight < 1024)
+      expect(req).assertEqual(true);
+    })
+    it('FIT_CENTER', 2, () => {
+      let reqSize: calculateScaleType =
+        new Downsampler().calculateScaling('jpg', 1024, 1024, 200,
+          200, DownsampleStrategy.FIT_CENTER, false)
+      let req = (reqSize.targetWidth < 1024 && reqSize.targetHeight < 1024)
+      expect(req).assertEqual(true);
+    })
+    it('CENTER_INSIDE', 3, () => {
+      let reqSize: calculateScaleType =
+        new Downsampler().calculateScaling('jpg', 1024, 1024, 200,
+          200, DownsampleStrategy.CENTER_INSIDE, false)
+      let req = (reqSize.targetWidth < 1024 && reqSize.targetHeight < 1024)
+      expect(req).assertEqual(true);
+    })
+    it('CENTER_OUTSIDE', 4, () => {
+      let reqSize: calculateScaleType =
+        new Downsampler().calculateScaling('jpg', 1024, 1024, 200,
+          200, DownsampleStrategy.CENTER_OUTSIDE, false)
+      let req = (reqSize.targetWidth < 1024 && reqSize.targetHeight < 1024)
+      expect(req).assertEqual(true);
+    })
+
+  })
+}

library/index.ets

@@ -67,3 +67,5 @@ export { CropTransformation } from './src/main/ets/transform/CropTransformation'
 export { MaskTransformation } from './src/main/ets/transform/MaskTransformation'
 
 export { SepiaTransformation } from './src/main/ets/transform/SepiaTransformation'
+
+export { DownsampleStrategy } from './src/main/ets/downsampling/DownsampleStartegy'

library/src/main/ets/ImageKnifeDispatcher.ets

@@ -40,6 +40,8 @@ import {
 } from './model/ImageKnifeData'
 import { combineArrayBuffers } from './model/utils';
 import { BusinessError } from '@kit.BasicServicesKit';
+import { Downsampler } from './downsampling/Downsampler';
+import { DownsampleStrategy } from './downsampling/DownsampleStartegy';
 
 export class ImageKnifeDispatcher {
   // 最大并发
@@ -189,7 +191,10 @@ export class ImageKnifeDispatcher {
       fileCacheFolder: ImageKnife.getInstance().getFileCache()?.getCacheFolder(),
       isAnimator:isAnimator,
       moduleName: moduleName == "" ? undefined : moduleName,
-      resName: resName == "" ? undefined : resName
+      resName: resName == "" ? undefined : resName,
+      targetWidth: currentRequest.componentWidth,
+      targetHeight: currentRequest.componentHeight,
+      downsampType: currentRequest.imageKnifeOption.downsampleOf,
     }
 
     if(request.customGetImage == undefined) {
@@ -651,6 +656,20 @@ async function requestJob(request: RequestJobRequest, requestList?: List<ImageKn
       editable: true,
       desiredSize: defaultSize
     };
+    let imageInfo = await imageSource.getImageInfo()
+    if ((request.downsampType !== DownsampleStrategy.NONE && request.downsampType !== undefined) &&
+      request.requestSource == ImageKnifeRequestSource.SRC) {
+      let reqSize =
+        new Downsampler().calculateScaling(typeValue, imageInfo.size.width, imageInfo.size.height, request.targetWidth,
+          request.targetHeight, request.downsampType)
+      opts = {
+        editable: true,
+        desiredSize: {
+          height: vp2px(reqSize.targetHeight),
+          width: vp2px(reqSize.targetWidth)
+        }
+      }
+    }
     await imageSource.createPixelMap(opts)
       .then((pixelmap: PixelMap) => {
         resPixelmap = pixelmap
@@ -663,6 +682,22 @@ async function requestJob(request: RequestJobRequest, requestList?: List<ImageKn
       type:typeValue
     };
   }
+
+  let imageInfo = await imageSource.getImageInfo()
+  if ((request.downsampType !== undefined && request.downsampType !== DownsampleStrategy.NONE) &&
+    request.requestSource == ImageKnifeRequestSource.SRC) {
+    let reqSize =
+      new Downsampler().calculateScaling(typeValue, imageInfo.size.width, imageInfo.size.height, request.targetWidth,
+        request.targetHeight, request.downsampType)
+
+    decodingOptions = {
+      editable: true,
+      desiredSize: {
+        width: reqSize.targetWidth,
+        height: reqSize.targetHeight
+      }
+    }
+  }
   let size = (await imageSource.getImageInfo()).size
   await imageSource.createPixelMap(decodingOptions)
     .then((pixelmap: PixelMap) => {

library/src/main/ets/ImageKnifeOption.ets

@@ -16,6 +16,7 @@ import taskpool from '@ohos.taskpool';
 import common from '@ohos.app.ability.common'
 import { CacheStrategy, ImageKnifeData,EventImage } from './model/ImageKnifeData';
 import { PixelMapTransformation } from './transform/PixelMapTransformation';
+import { DownsampleStrategy } from './downsampling/DownsampleStartegy';
 import { drawing } from '@kit.ArkGraphics2D';
 
 export interface HeaderOptions {
@@ -90,6 +91,8 @@ interface ImageOption {
   onLoadListener?: OnLoadCallBack | undefined;
   onComplete?:(event:EventImage | undefined) => void
   drawingColorFilter?: ColorFilter | drawing.ColorFilter
+  downsampleOf?: DownsampleStrategy
+
 }
 @ObservedV2
 export class ImageKnifeOption {
@@ -121,6 +124,9 @@ export class ImageKnifeOption {
   onLoadListener?: OnLoadCallBack | undefined;
   onComplete?:(event:EventImage | undefined) => void
   drawingColorFilter?: ColorFilter | drawing.ColorFilter
+  // 下采样
+  downsampleOf?: DownsampleStrategy = DownsampleStrategy.NONE
+
   constructor(option?:ImageOption) {
     this.loadSrc = option?.loadSrc == undefined ? "" : option?.loadSrc
     this.placeholderSrc = option?.placeholderSrc
@@ -141,6 +147,7 @@ export class ImageKnifeOption {
     this.onLoadListener = option?.onLoadListener
     this.onComplete = option?.onComplete
     this.drawingColorFilter = option?.drawingColorFilter
+    this.downsampleOf = option?.downsampleOf
   }
 }
 

library/src/main/ets/ImageKnifeRequest.ets

@@ -15,7 +15,7 @@
 import { ImageKnifeOption } from './ImageKnifeOption';
 import common from '@ohos.app.ability.common';
 import { ImageKnifeRequestSource } from './model/ImageKnifeData';
-
+import { DownsampleStrategy } from './downsampling/DownsampleStartegy';
 
 export class ImageKnifeRequest {
   requestState: ImageKnifeRequestState = ImageKnifeRequestState.PROGRESS
@@ -27,18 +27,22 @@ export class ImageKnifeRequest {
   ImageKnifeRequestCallback: ImageKnifeRequestCallback
   componentVersion: number = 0
   headers: Map<string,Object> = new Map<string,Object>()
+  downsampType?: DownsampleStrategy
   constructor(option: ImageKnifeOption,
     uIAbilityContext: common.UIAbilityContext,
     width: number,
     height: number,
     version: number,
-              ImageKnifeRequestCallback: ImageKnifeRequestCallback) {
+    ImageKnifeRequestCallback: ImageKnifeRequestCallback,
+    downsampType?: DownsampleStrategy,
+  ) {
     this.imageKnifeOption = option
     this.context = uIAbilityContext
     this.componentWidth = width
     this.componentHeight = height
     this.componentVersion = version
     this.ImageKnifeRequestCallback = ImageKnifeRequestCallback
+    this.downsampType = downsampType
   }
   // RequestOption调用header对于的方法
   addHeader(key: string, value: Object) {

library/src/main/ets/downsampling/BaseDownsampling.ets

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2024 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { DownsampleStrategy } from './DownsampleStartegy';
+
+import { SampleSizeRounding } from './DownsampleUtils';
+
+export interface BaseDownsampling {
+  getName(): string
+
+  getScaleFactor(sourceWidth: number, sourceHeight: number, requestWidth: number, requestHeight: number,downsampType?:DownsampleStrategy): number
+
+  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestWidth: number,
+    requestHeight: number,downsampType?:DownsampleStrategy): SampleSizeRounding
+}

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

@@ -0,0 +1,184 @@
+/*
+ * Copyright (C) 2024 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { BaseDownsampling } from './BaseDownsampling';
+import { highestOneBit, SampleSizeRounding } from './DownsampleUtils';
+
+export class FitCenter implements BaseDownsampling {
+  getName() {
+    return "FitCenter"
+  }
+
+  getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy
+    ): number {
+    if (downsampType===DownsampleStrategy.FIT_CENTER_QUALITY) {
+      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;
+    }
+  }
+
+  //实现 getSampleSizeRounding 方法
+  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy
+    ): number {
+    if (downsampType===DownsampleStrategy.FIT_CENTER_QUALITY) {
+      return SampleSizeRounding.QUALITY;
+    } else {
+      return SampleSizeRounding.MEMORY;
+    }
+
+  }
+}
+
+export class None implements BaseDownsampling {
+  getName(): string {
+    return "DownsampleNone"
+  }
+
+  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;
+  }
+
+  //实现 getSampleSizeRounding 方法
+  public getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number,
+    requestedHeight: number): SampleSizeRounding {
+    return SampleSizeRounding.QUALITY
+
+  }
+}
+
+
+/*宽高进行等比缩放宽高里面最小的比例先放进去
+然后再更据原图的缩放比去适配另一边*/
+
+export class CenterOutside implements BaseDownsampling {
+  getName() {
+    return "CenterOutside"
+  }
+
+  getScaleFactor(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number): number {
+    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);
+  }
+
+  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number,
+    requestedHeight: number): SampleSizeRounding {
+    //根据 CenterOutside 的逻辑，总是返回 QUALITY
+    return SampleSizeRounding.QUALITY;
+  }
+}
+
+/*请求尺寸大于实际尺寸不进行放大,按照原图展示*/
+
+export class AtMost implements BaseDownsampling {
+  getName() {
+    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));
+    let greaterOrEqualSampleSize = lesserOrEqualSampleSize
+    if (lesserOrEqualSampleSize < maxIntegerFactor) {
+      greaterOrEqualSampleSize = lesserOrEqualSampleSize <<= 1;
+    }
+    greaterOrEqualSampleSize = lesserOrEqualSampleSize << (lesserOrEqualSampleSize < maxIntegerFactor ? 1 : 0)
+    //返回缩放因子
+    return 1 / greaterOrEqualSampleSize
+  }
+
+
+  getSampleSizeRounding(sourceWidth: number, sourceHeight: number, requestedWidth: number,
+    requestHeight: number): SampleSizeRounding {
+    //根据 AtMost 的逻辑，总是返回 MEMORY
+    return SampleSizeRounding.MEMORY
+  }
+}
+
+/*宽高进行等比缩放宽高里面最大的比例先放进去
+然后再更据原图的缩放比去适配另一边*/
+export class CenterInside implements BaseDownsampling {
+  getName() {
+    return "CenterInside"
+  }
+
+  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);
+
+  }
+
+  getScale(sourceWidth: number, sourceHeight: number, requestedWidth: number, requestedHeight: number,downsampType:DownsampleStrategy
+    ): number {
+    if (downsampType===DownsampleStrategy.FIT_CENTER_QUALITY) {
+      const widthPercentage = requestedWidth / sourceWidth
+      const heightPercentage = requestedHeight / sourceHeight
+      return Math.min(widthPercentage, heightPercentage)
+    } else {
+      //类似 AT_LEAST,但只要求一个维度或另一个维度大于等于请求的尺寸
+      const maxIntegerFactor = Math.max(sourceHeight / requestedHeight, sourceWidth / requestedWidth);
+      return maxIntegerFactor === 0 ? 1 : 1 / highestOneBit(maxIntegerFactor);
+
+    }
+  }
+
+  getSampleSizeRounding(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) {
+      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
+    ): SampleSizeRounding {
+    if (downsampType===DownsampleStrategy.CENTER_INSIDE_QUALITY) {
+      return SampleSizeRounding.QUALITY;
+    } else {
+      return SampleSizeRounding.MEMORY;
+    }
+  }
+}
+
+export enum DownsampleStrategy {
+  //请求尺寸大于实际尺寸不进行放大
+  AT_MOST,
+  //两边自适应内存优先
+  FIT_CENTER_MEMORY  ,
+  //两边自适应质量优先
+  FIT_CENTER_QUALITY,
+  //按照宽高比的最大比进行适配内存优先
+  CENTER_INSIDE_MEMORY ,
+  //按照宽高比的最大比进行适配质量优先
+  CENTER_INSIDE_QUALITY,
+  //宽高进行等比缩放宽高里面最小的比例先放进去，然后再根据原图的缩放比去适配
+  CENTER_OUTSIDE,
+  //不进行降采样
+  NONE,
+}

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

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2024 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+export enum SampleSizeRounding {
+  /**
+   * Prefer to round the sample size up so that the image is downsampled to smaller than the
+   * requested size to use less memory.
+   */
+  //（内存优先）
+  MEMORY,
+  /**
+   * Prefer to round the sample size down so that the image is downsampled to larger than the
+   * requested size to maintain quality at the expense of extra memory usage.
+   */
+  //（质量优先）
+  QUALITY
+}
+export function highestOneBit(i: number): number {
+  i |= (i >> 1);
+  i |= (i >> 2);
+  i |= (i >> 4);
+  i |= (i >> 8);
+  i |= (i >> 16);
+  return i - (i >>> 1);
+}

library/src/main/ets/downsampling/Downsampler.ets

@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2024 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {
+  AtMost,
+  CenterInside,
+  CenterOutside,
+  DownsampleStrategy,
+  FitCenter,
+  None,
+} from './DownsampleStartegy';
+import { highestOneBit, SampleSizeRounding } from './DownsampleUtils';
+
+export interface calculateScaleType {
+  targetWidth: number,
+  targetHeight: number
+}
+
+export class Downsampler {
+  calculateScaling(
+    typeValue: string | null,
+    sourceHeight: number, //原始宽高
+    sourceWidth: number | undefined, //原始宽高
+    requestHeight: number, //请求宽高
+    requestWidth: number, //请求宽高
+    downsampType: DownsampleStrategy | undefined,
+
+  ): calculateScaleType {
+    let degreesToRotate: ESObject = 90;
+    const fileType = typeValue //获取图片类型
+    let powerOfTwoWidth: number | null = null;
+    let powerOfTwoHeight: number | null = null;
+    let targetWidth: number = 0
+    let targetHeight: number = 0
+
+    if (sourceHeight <= 0 || sourceWidth == undefined || sourceWidth == null || sourceWidth <= 0) {
+      throw new Error("Cannot found width or height");
+    }
+    let orientedSourceWidth = sourceWidth;
+    let orientedSourceHeight = sourceHeight;
+    if (this.isRotationRequired(degreesToRotate)) {
+      orientedSourceWidth = sourceHeight;
+      orientedSourceHeight = sourceWidth;
+    }
+    if (requestWidth && !requestHeight) {
+      targetWidth = this.round((requestHeight) * orientedSourceWidth / orientedSourceHeight)
+    } else if (requestHeight && !requestWidth) {
+      targetHeight = this.round((requestWidth) * orientedSourceHeight / orientedSourceWidth)
+    } else if (requestHeight && requestWidth) {
+      targetWidth =
+        requestHeight == sourceWidth ? (this.isRotationRequired(degreesToRotate) ? sourceHeight : sourceWidth) :
+          requestWidth;
+      targetHeight =
+        requestHeight == sourceHeight ? (this.isRotationRequired(degreesToRotate) ? sourceWidth : sourceHeight) :
+          requestWidth;
+    } else {
+      throw new Error("Cannot found width or height");
+    }
+    let exactScaleFactor: number | undefined
+    let rounding: SampleSizeRounding | undefined
+    switch (downsampType) {
+      case DownsampleStrategy.FIT_CENTER_MEMORY || DownsampleStrategy.FIT_CENTER_QUALITY:
+        exactScaleFactor = new FitCenter()
+          .getScaleFactor(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight,downsampType)
+        rounding = new FitCenter()
+          .getSampleSizeRounding(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight,downsampType)
+        break;
+      case DownsampleStrategy.NONE:
+        exactScaleFactor = new None()
+          .getScaleFactor(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+        rounding = new None()
+          .getSampleSizeRounding(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+        break
+      case DownsampleStrategy.AT_MOST:
+        exactScaleFactor = new AtMost()
+          .getScaleFactor(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+        rounding = new AtMost()
+          .getSampleSizeRounding(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+        break
+      case DownsampleStrategy.CENTER_INSIDE_MEMORY || DownsampleStrategy.CENTER_INSIDE_QUALITY:
+        exactScaleFactor = new CenterInside()
+          .getScaleFactor(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight,downsampType)
+        rounding = new CenterInside()
+          .getSampleSizeRounding(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight,downsampType)
+        break
+
+      case DownsampleStrategy.CENTER_OUTSIDE:
+        exactScaleFactor = new CenterOutside()
+          .getScaleFactor(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+        rounding = new CenterOutside()
+          .getSampleSizeRounding(orientedSourceWidth, orientedSourceHeight, targetWidth, targetHeight)
+        break
+    }
+    if (exactScaleFactor==undefined|| exactScaleFactor <= 0 ) {
+      throw new Error("Cannot round with exactScaleFactor");
+    }
+    if (rounding == undefined) {
+      throw new Error("Cannot round with null rounding");
+    }
+    let outWidth: number = this.round(exactScaleFactor * orientedSourceWidth);
+    let outHeight: number = this.round(exactScaleFactor * orientedSourceHeight);
+    let widthScaleFactor = orientedSourceWidth / outWidth;
+    let heightScaleFactor = orientedSourceHeight / outHeight;
+    let scaleFactor = rounding ==SampleSizeRounding.QUALITY ? 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 = scaleFactor;
+    powerOfTwoSampleSize = Math.max(1, highestOneBit(scaleFactor))
+    if (rounding == 1 && (powerOfTwoSampleSize < (1 / exactScaleFactor))) {
+      powerOfTwoSampleSize = powerOfTwoSampleSize << 1;
+    }
+    //基于上一步得出的采样大小，根据不同的图片类型，计算采样后的图片尺寸
+    if (fileType === "png") {
+      powerOfTwoWidth = Math.floor(orientedSourceWidth / powerOfTwoSampleSize);
+      powerOfTwoHeight = Math.floor(orientedSourceHeight / powerOfTwoSampleSize);
+    } else if (fileType === "webp") {
+      powerOfTwoWidth = Math.round(orientedSourceWidth / powerOfTwoSampleSize);
+      powerOfTwoHeight = Math.round(orientedSourceHeight / powerOfTwoSampleSize);
+    } else {
+      powerOfTwoWidth = orientedSourceWidth / powerOfTwoSampleSize;
+      powerOfTwoHeight = orientedSourceHeight / powerOfTwoSampleSize;
+    }
+    let a: calculateScaleType = {
+      "targetWidth": powerOfTwoWidth,
+      "targetHeight": powerOfTwoHeight
+    }
+    return a
+  }
+
+  round(value: number): number {
+    return Math.floor(value + 0.5);
+  }
+
+  isRotationRequired(degreesToRotate: number): boolean {
+    return degreesToRotate == 90 || degreesToRotate == 270;
+  }
+}

library/src/main/ets/key/DefaultEngineKey.ets

@@ -17,6 +17,7 @@ import { ImageKnifeOption } from '../ImageKnifeOption';
 import { IEngineKey } from './IEngineKey';
 import { PixelMapTransformation } from '../transform/PixelMapTransformation';
 import { ImageKnifeRequestSource } from '../model/ImageKnifeData';
+import { DownsampleStrategy } from '../downsampling/DownsampleStartegy';
 
 @Sendable
 export class DefaultEngineKey implements IEngineKey {
@@ -31,6 +32,9 @@ export class DefaultEngineKey implements IEngineKey {
       if (imageKnifeOption.transformation) {
         key += "transformation=" + this.getTransformation(imageKnifeOption.transformation) + ";"
       }
+      if ((imageKnifeOption.downsampleOf !== DownsampleStrategy.NONE && imageKnifeOption.downsampleOf !== undefined)) {
+        key += "downsampleOf" + imageKnifeOption.downsampleOf +"width="+width+"height="+ height
+      }
     }
     return key
   }

library/src/main/ets/model/ImageKnifeData.ets

@@ -18,7 +18,7 @@ import { IEngineKey } from '../key/IEngineKey'
 import { PixelMapTransformation } from '../transform/PixelMapTransformation'
 import common from '@ohos.app.ability.common';
 import { Size } from '@kit.ArkUI'
-
+import { DownsampleStrategy } from '../downsampling/DownsampleStartegy'
 export interface ImageKnifeData {
   source: PixelMap | string,
   imageWidth: number,
@@ -103,6 +103,9 @@ export interface RequestJobRequest {
   fileCacheFolder: string,
   isAnimator?: boolean,
   moduleName?:string,
-  resName?: string
+  resName?: string,
+  targetWidth: number
+  targetHeight: number
+  downsampType?: DownsampleStrategy
 }