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import fs from '@ohos.file.fs';
import { image } from '@kit.ImageKit';
import { resourceManager } from '@kit.LocalizationKit';
import { Base64Util } from './Base64Util';
import { FileUtil } from './FileUtil';
import { ResUtil } from './ResUtil';
import { DateUtil } from './DateUtil';
import { PreviewUtil } from './PreviewUtil';/*** 图片工具类* 提供图片处理相关功能，如压缩、转换、保存等。* author: 鸿蒙布道师* since: 2025/04/17*/
export class ImageUtil {/*** 将 Base64 字符串转换为 PixelMap* @param base64 Base64 格式的图片字符串* @returns Promise<image.PixelMap>*/static async base64ToPixelMap(base64: string): Promise<image.PixelMap> {if (!base64) throw new Error("Base64 string cannot be empty.");const reg = /data:image\/\w+;base64,/;const base64Str = base64.replace(reg, '');const arrayBuffer = Base64Util.decodeSync(base64Str).buffer as ArrayBuffer;const imageSource = image.createImageSource(arrayBuffer);return imageSource.createPixelMap({ editable: false });}/*** 将 PixelMap 转换为 Base64 字符串* @param pixelMap 图片的 PixelMap 对象* @param format 图片格式，默认为 'image/png'* @returns Promise<string>*/static async pixelMapToBase64Str(pixelMap: image.PixelMap, format: string = 'image/png'): Promise<string> {if (!pixelMap) throw new Error("PixelMap cannot be null.");const packOpts: image.PackingOption = { format, quality: 100 };const arrayBuffer = await ImageUtil.packingFromPixelMap(pixelMap, packOpts);const base64Str = Base64Util.encodeToStrSync(new Uint8Array(arrayBuffer));const headStr = `data:${format};base64,`;return base64Str.startsWith(headStr) ? base64Str : headStr + base64Str;}/*** 保存 PixelMap 到指定路径* @param pixelMap 图片的 PixelMap 对象* @param path 保存路径* @param name 文件名* @param format 图片格式，默认为 'image/png'* @returns Promise<string> 返回文件保存路径*/static async savePixelMap(pixelMap: image.PixelMap, path: string, name: string, format: string = 'image/png'): Promise<string> {if (!path || !name) throw new Error("Path and name cannot be empty.");if (!FileUtil.accessSync(path)) FileUtil.mkdirSync(path);const filePath = `${path}${FileUtil.separator}${name}`;const file = FileUtil.openSync(filePath);const packOpts: image.PackingOption = { format, quality: 100 };await ImageUtil.packToFileFromPixelMap(pixelMap, file.fd, packOpts);FileUtil.closeSync(file.fd);return filePath;}/*** 保存 ImageSource 到指定路径* @param source 图片的 ImageSource 对象* @param path 保存路径* @param name 文件名* @param format 图片格式，默认为 'image/png'* @returns Promise<string> 返回文件保存路径*/static async saveImageSource(source: image.ImageSource, path: string, name: string, format: string = 'image/png'): Promise<string> {if (!path || !name) throw new Error("Path and name cannot be empty.");if (!FileUtil.accessSync(path)) FileUtil.mkdirSync(path);const filePath = `${path}${FileUtil.separator}${name}`;const file = FileUtil.openSync(filePath);const packOpts: image.PackingOption = { format, quality: 100 };await ImageUtil.packToFileFromImageSource(source, file.fd, packOpts);FileUtil.closeSync(file.fd);return filePath;}/*** 创建 ImageSource 对象* @param src 图片资源（路径、资源 ID、ArrayBuffer 或 RawFileDescriptor）* @param options 可选的 SourceOptions* @returns image.ImageSource*/static createImageSource(src: string | number | ArrayBuffer | resourceManager.RawFileDescriptor,options?: image.SourceOptions): image.ImageSource {if (!src) throw new Error("Source cannot be empty.");if (typeof src === "string") {return options ? image.createImageSource(src, options) : image.createImageSource(src);} else if (typeof src === "number") {return options ? image.createImageSource(src, options) : image.createImageSource(src);} else if (src instanceof ArrayBuffer) {return options ? image.createImageSource(src, options) : image.createImageSource(src);} else {// Assume it's a RawFileDescriptorreturn options ? image.createImageSource(src, options) : image.createImageSource(src);}}/*** 使用增量方式创建 ImageSource* @param buf 图片数据缓冲区* @param options 可选的 SourceOptions* @returns image.ImageSource*/static createIncrementalSource(buf: ArrayBuffer, options?: image.SourceOptions): image.ImageSource {if (!buf) throw new Error("Buffer cannot be empty.");return options ? image.CreateIncrementalSource(buf, options) : image.CreateIncrementalSource(buf);}/*** 将 PixelMap 打包为 ArrayBuffer* @param source PixelMap 对象* @param options 打包选项* @returns Promise<ArrayBuffer>*/static packingFromPixelMap(source: image.PixelMap, options: image.PackingOption): Promise<ArrayBuffer> {const imagePacker = image.createImagePacker();return imagePacker.packing(source, options).finally(() => imagePacker.release());}/*** 将 ImageSource 打包为 ArrayBuffer* @param source ImageSource 对象* @param options 打包选项* @returns Promise<ArrayBuffer>*/static packingFromImageSource(source: image.ImageSource, options: image.PackingOption): Promise<ArrayBuffer> {const imagePacker = image.createImagePacker();return imagePacker.packing(source, options).finally(() => imagePacker.release());}/*** 将 PixelMap 打包并写入文件* @param source PixelMap 对象* @param fd 文件描述符* @param options 打包选项* @returns Promise<void>*/static packToFileFromPixelMap(source: image.PixelMap, fd: number, options: image.PackingOption): Promise<void> {const imagePacker = image.createImagePacker();return imagePacker.packToFile(source, fd, options).finally(() => imagePacker.release());}/*** 将 ImageSource 打包并写入文件* @param source ImageSource 对象* @param fd 文件描述符* @param options 打包选项* @returns Promise<void>*/static packToFileFromImageSource(source: image.ImageSource, fd: number, options: image.PackingOption): Promise<void> {const imagePacker = image.createImagePacker();return imagePacker.packToFile(source, fd, options).finally(() => imagePacker.release());}/*** 从资源获取 PixelMap* @param resource 资源对象* @param options 解码选项* @returns Promise<image.PixelMap>*/static async getPixelMapFromMedia(resource: Resource, options?: image.DecodingOptions): Promise<image.PixelMap> {const uint8Array = await ResUtil.getMediaContent(resource);return ImageUtil.createImageSource(uint8Array.buffer).createPixelMap(options);}/*** 压缩图片* @param sourcePixelMap 原始 PixelMap* @param maxImgSize 最大图片大小（单位：KB）* @param imageFormat 图片格式，默认为 'image/jpeg'* @returns Promise<ArrayBuffer>*/static async compressedImage(sourcePixelMap: image.PixelMap, maxImgSize: number, imageFormat: string = "image/jpeg"): Promise<ArrayBuffer> {if (!sourcePixelMap) throw new Error("PixelMap cannot be null.");if (maxImgSize <= 0) throw new Error("Max image size must be greater than 0.");const imagePacker = image.createImagePacker();const packOpts: image.PackingOption = { format: imageFormat, quality: 0 };let compressedImageData = await imagePacker.packing(sourcePixelMap, packOpts);const maxCompressedImageByte = maxImgSize * 1024;if (compressedImageData.byteLength > maxCompressedImageByte) {compressedImageData = await ImageUtil.compressWithScale(sourcePixelMap, maxCompressedImageByte, imageFormat);} else {compressedImageData = await ImageUtil.compressWithQuality(sourcePixelMap, maxCompressedImageByte, imageFormat);}imagePacker.release();return compressedImageData;}/*** 将 PixelMap 打包为 ArrayBuffer* @param sourcePixelMap 图片的 PixelMap 对象* @param imageQuality 图片质量* @param imageFormat 图片格式，默认为 'image/jpeg'* @returns Promise<ArrayBuffer>*/static async packing(sourcePixelMap: image.PixelMap,imageQuality: number,imageFormat: string = "image/jpeg"): Promise<ArrayBuffer> {const imagePacker = image.createImagePacker();const packOpts: image.PackingOption = { format: imageFormat, quality: imageQuality };const data: ArrayBuffer = await imagePacker.packing(sourcePixelMap, packOpts);imagePacker.release();return data;}/*** 使用质量压缩图片* @param sourcePixelMap 原始 PixelMap* @param maxCompressedImageByte 最大字节数* @param imageFormat 图片格式* @returns Promise<ArrayBuffer>*/private static async compressWithQuality(sourcePixelMap: image.PixelMap,maxCompressedImageByte: number,imageFormat: string): Promise<ArrayBuffer> {// 生成从 0 到 100 的质量数组，步长为 10const qualities: number[] = [];for (let i = 0; i <= 10; i++) {qualities.push(i * 10);}let left = 0, right = qualities.length - 1;// 使用二分查找法寻找最佳质量while (left <= right) {const mid = Math.floor((left + right) / 2);const quality = qualities[mid];const data: ArrayBuffer = await ImageUtil.packing(sourcePixelMap, quality, imageFormat);if (data.byteLength <= maxCompressedImageByte) {left = mid + 1;} else {right = mid - 1;}}// 返回找到的最佳质量对应的压缩图片数据return ImageUtil.packing(sourcePixelMap, qualities[right], imageFormat);}/*** 使用缩放压缩图片* @param sourcePixelMap 原始 PixelMap* @param maxCompressedImageByte 最大字节数* @param imageFormat 图片格式* @returns Promise<ArrayBuffer>*/private static async compressWithScale(sourcePixelMap: image.PixelMap,maxCompressedImageByte: number,imageFormat: string): Promise<ArrayBuffer> {let scale = 1, step = 0.4;while (true) {scale -= step;if (scale <= 0) break;await sourcePixelMap.scale(scale, scale);const data = await ImageUtil.packing(sourcePixelMap, 0, imageFormat);if (data.byteLength <= maxCompressedImageByte) {return data;}}throw new Error("Failed to compress image within the specified size limit.");}/*** 压缩图片并保存* @param uri 图片 URI* @param maxSize 最大图片大小（单位：KB）* @param imageFormat 图片格式* @returns Promise<string> 返回保存路径*/static async compressPhoto(uri: string, maxSize: number, imageFormat?: string): Promise<string> {if (!uri) throw new Error("URI cannot be empty.");if (maxSize <= 0) throw new Error("Max size must be greater than 0.");imageFormat = imageFormat ?? PreviewUtil.getMimeType(FileUtil.getFileExtention(uri));const srcFile = await FileUtil.open(uri, fs.OpenMode.READ_ONLY);const pixelMap = await ImageUtil.createImageSource(srcFile.fd).createPixelMap();const arrayBuffer = await ImageUtil.compressedImage(pixelMap, maxSize, imageFormat);const filePath = FileUtil.getTempDirPath(DateUtil.getTodayStr("yyyy-MM-dd"), srcFile.name);await FileUtil.writeEasy(filePath, arrayBuffer, false);FileUtil.closeSync(srcFile.fd);pixelMap.release();return filePath;}
}
代码如下：

import fs from '@ohos.file.fs';
import { image } from '@kit.ImageKit';
import { resourceManager } from '@kit.LocalizationKit';
import { Base64Util } from './Base64Util';
import { FileUtil } from './FileUtil';
import { ResUtil } from './ResUtil';
import { DateUtil } from './DateUtil';
import { PreviewUtil } from './PreviewUtil';/*** 图片工具类* 提供图片处理相关功能，如压缩、转换、保存等。* author: 鸿蒙布道师* since: 2025/04/17*/
export class ImageUtil {/*** 将 Base64 字符串转换为 PixelMap* @param base64 Base64 格式的图片字符串* @returns Promise<image.PixelMap>*/static async base64ToPixelMap(base64: string): Promise<image.PixelMap> {if (!base64) throw new Error("Base64 string cannot be empty.");const reg = /data:image\/\w+;base64,/;const base64Str = base64.replace(reg, '');const arrayBuffer = Base64Util.decodeSync(base64Str).buffer as ArrayBuffer;const imageSource = image.createImageSource(arrayBuffer);return imageSource.createPixelMap({ editable: false });}/*** 将 PixelMap 转换为 Base64 字符串* @param pixelMap 图片的 PixelMap 对象* @param format 图片格式，默认为 'image/png'* @returns Promise<string>*/static async pixelMapToBase64Str(pixelMap: image.PixelMap, format: string = 'image/png'): Promise<string> {if (!pixelMap) throw new Error("PixelMap cannot be null.");const packOpts: image.PackingOption = { format, quality: 100 };const arrayBuffer = await ImageUtil.packingFromPixelMap(pixelMap, packOpts);const base64Str = Base64Util.encodeToStrSync(new Uint8Array(arrayBuffer));const headStr = `data:${format};base64,`;return base64Str.startsWith(headStr) ? base64Str : headStr + base64Str;}/*** 保存 PixelMap 到指定路径* @param pixelMap 图片的 PixelMap 对象* @param path 保存路径* @param name 文件名* @param format 图片格式，默认为 'image/png'* @returns Promise<string> 返回文件保存路径*/static async savePixelMap(pixelMap: image.PixelMap, path: string, name: string, format: string = 'image/png'): Promise<string> {if (!path || !name) throw new Error("Path and name cannot be empty.");if (!FileUtil.accessSync(path)) FileUtil.mkdirSync(path);const filePath = `${path}${FileUtil.separator}${name}`;const file = FileUtil.openSync(filePath);const packOpts: image.PackingOption = { format, quality: 100 };await ImageUtil.packToFileFromPixelMap(pixelMap, file.fd, packOpts);FileUtil.closeSync(file.fd);return filePath;}/*** 保存 ImageSource 到指定路径* @param source 图片的 ImageSource 对象* @param path 保存路径* @param name 文件名* @param format 图片格式，默认为 'image/png'* @returns Promise<string> 返回文件保存路径*/static async saveImageSource(source: image.ImageSource, path: string, name: string, format: string = 'image/png'): Promise<string> {if (!path || !name) throw new Error("Path and name cannot be empty.");if (!FileUtil.accessSync(path)) FileUtil.mkdirSync(path);const filePath = `${path}${FileUtil.separator}${name}`;const file = FileUtil.openSync(filePath);const packOpts: image.PackingOption = { format, quality: 100 };await ImageUtil.packToFileFromImageSource(source, file.fd, packOpts);FileUtil.closeSync(file.fd);return filePath;}/*** 创建 ImageSource 对象* @param src 图片资源（路径、资源 ID、ArrayBuffer 或 RawFileDescriptor）* @param options 可选的 SourceOptions* @returns image.ImageSource*/static createImageSource(src: string | number | ArrayBuffer | resourceManager.RawFileDescriptor,options?: image.SourceOptions): image.ImageSource {if (!src) throw new Error("Source cannot be empty.");if (typeof src === "string") {return options ? image.createImageSource(src, options) : image.createImageSource(src);} else if (typeof src === "number") {return options ? image.createImageSource(src, options) : image.createImageSource(src);} else if (src instanceof ArrayBuffer) {return options ? image.createImageSource(src, options) : image.createImageSource(src);} else {// Assume it's a RawFileDescriptorreturn options ? image.createImageSource(src, options) : image.createImageSource(src);}}/*** 使用增量方式创建 ImageSource* @param buf 图片数据缓冲区* @param options 可选的 SourceOptions* @returns image.ImageSource*/static createIncrementalSource(buf: ArrayBuffer, options?: image.SourceOptions): image.ImageSource {if (!buf) throw new Error("Buffer cannot be empty.");return options ? image.CreateIncrementalSource(buf, options) : image.CreateIncrementalSource(buf);}/*** 将 PixelMap 打包为 ArrayBuffer* @param source PixelMap 对象* @param options 打包选项* @returns Promise<ArrayBuffer>*/static packingFromPixelMap(source: image.PixelMap, options: image.PackingOption): Promise<ArrayBuffer> {const imagePacker = image.createImagePacker();return imagePacker.packing(source, options).finally(() => imagePacker.release());}/*** 将 ImageSource 打包为 ArrayBuffer* @param source ImageSource 对象* @param options 打包选项* @returns Promise<ArrayBuffer>*/static packingFromImageSource(source: image.ImageSource, options: image.PackingOption): Promise<ArrayBuffer> {const imagePacker = image.createImagePacker();return imagePacker.packing(source, options).finally(() => imagePacker.release());}/*** 将 PixelMap 打包并写入文件* @param source PixelMap 对象* @param fd 文件描述符* @param options 打包选项* @returns Promise<void>*/static packToFileFromPixelMap(source: image.PixelMap, fd: number, options: image.PackingOption): Promise<void> {const imagePacker = image.createImagePacker();return imagePacker.packToFile(source, fd, options).finally(() => imagePacker.release());}/*** 将 ImageSource 打包并写入文件* @param source ImageSource 对象* @param fd 文件描述符* @param options 打包选项* @returns Promise<void>*/static packToFileFromImageSource(source: image.ImageSource, fd: number, options: image.PackingOption): Promise<void> {const imagePacker = image.createImagePacker();return imagePacker.packToFile(source, fd, options).finally(() => imagePacker.release());}/*** 从资源获取 PixelMap* @param resource 资源对象* @param options 解码选项* @returns Promise<image.PixelMap>*/static async getPixelMapFromMedia(resource: Resource, options?: image.DecodingOptions): Promise<image.PixelMap> {const uint8Array = await ResUtil.getMediaContent(resource);return ImageUtil.createImageSource(uint8Array.buffer).createPixelMap(options);}/*** 压缩图片* @param sourcePixelMap 原始 PixelMap* @param maxImgSize 最大图片大小（单位：KB）* @param imageFormat 图片格式，默认为 'image/jpeg'* @returns Promise<ArrayBuffer>*/static async compressedImage(sourcePixelMap: image.PixelMap, maxImgSize: number, imageFormat: string = "image/jpeg"): Promise<ArrayBuffer> {if (!sourcePixelMap) throw new Error("PixelMap cannot be null.");if (maxImgSize <= 0) throw new Error("Max image size must be greater than 0.");const imagePacker = image.createImagePacker();const packOpts: image.PackingOption = { format: imageFormat, quality: 0 };let compressedImageData = await imagePacker.packing(sourcePixelMap, packOpts);const maxCompressedImageByte = maxImgSize * 1024;if (compressedImageData.byteLength > maxCompressedImageByte) {compressedImageData = await ImageUtil.compressWithScale(sourcePixelMap, maxCompressedImageByte, imageFormat);} else {compressedImageData = await ImageUtil.compressWithQuality(sourcePixelMap, maxCompressedImageByte, imageFormat);}imagePacker.release();return compressedImageData;}/*** 将 PixelMap 打包为 ArrayBuffer* @param sourcePixelMap 图片的 PixelMap 对象* @param imageQuality 图片质量* @param imageFormat 图片格式，默认为 'image/jpeg'* @returns Promise<ArrayBuffer>*/static async packing(sourcePixelMap: image.PixelMap,imageQuality: number,imageFormat: string = "image/jpeg"): Promise<ArrayBuffer> {const imagePacker = image.createImagePacker();const packOpts: image.PackingOption = { format: imageFormat, quality: imageQuality };const data: ArrayBuffer = await imagePacker.packing(sourcePixelMap, packOpts);imagePacker.release();return data;}/*** 使用质量压缩图片* @param sourcePixelMap 原始 PixelMap* @param maxCompressedImageByte 最大字节数* @param imageFormat 图片格式* @returns Promise<ArrayBuffer>*/private static async compressWithQuality(sourcePixelMap: image.PixelMap,maxCompressedImageByte: number,imageFormat: string): Promise<ArrayBuffer> {// 生成从 0 到 100 的质量数组，步长为 10const qualities: number[] = [];for (let i = 0; i <= 10; i++) {qualities.push(i * 10);}let left = 0, right = qualities.length - 1;// 使用二分查找法寻找最佳质量while (left <= right) {const mid = Math.floor((left + right) / 2);const quality = qualities[mid];const data: ArrayBuffer = await ImageUtil.packing(sourcePixelMap, quality, imageFormat);if (data.byteLength <= maxCompressedImageByte) {left = mid + 1;} else {right = mid - 1;}}// 返回找到的最佳质量对应的压缩图片数据return ImageUtil.packing(sourcePixelMap, qualities[right], imageFormat);}/*** 使用缩放压缩图片* @param sourcePixelMap 原始 PixelMap* @param maxCompressedImageByte 最大字节数* @param imageFormat 图片格式* @returns Promise<ArrayBuffer>*/private static async compressWithScale(sourcePixelMap: image.PixelMap,maxCompressedImageByte: number,imageFormat: string): Promise<ArrayBuffer> {let scale = 1, step = 0.4;while (true) {scale -= step;if (scale <= 0) break;await sourcePixelMap.scale(scale, scale);const data = await ImageUtil.packing(sourcePixelMap, 0, imageFormat);if (data.byteLength <= maxCompressedImageByte) {return data;}}throw new Error("Failed to compress image within the specified size limit.");}/*** 压缩图片并保存* @param uri 图片 URI* @param maxSize 最大图片大小（单位：KB）* @param imageFormat 图片格式* @returns Promise<string> 返回保存路径*/static async compressPhoto(uri: string, maxSize: number, imageFormat?: string): Promise<string> {if (!uri) throw new Error("URI cannot be empty.");if (maxSize <= 0) throw new Error("Max size must be greater than 0.");imageFormat = imageFormat ?? PreviewUtil.getMimeType(FileUtil.getFileExtention(uri));const srcFile = await FileUtil.open(uri, fs.OpenMode.READ_ONLY);const pixelMap = await ImageUtil.createImageSource(srcFile.fd).createPixelMap();const arrayBuffer = await ImageUtil.compressedImage(pixelMap, maxSize, imageFormat);const filePath = FileUtil.getTempDirPath(DateUtil.getTodayStr("yyyy-MM-dd"), srcFile.name);await FileUtil.writeEasy(filePath, arrayBuffer, false);FileUtil.closeSync(srcFile.fd);pixelMap.release();return filePath;}
}