图片格式转换 - OpenHarmony开发者论坛

import common from '@ohos.app.ability.common';
@Entry
@Component
struct Index {
...
context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext
...
async getPixelMap(){
// 获取resourceManager资源管理
const resourceMgr = this.context.resourceManager
// 获取rawfile文件夹下imagetransfer.PNG的ArrayBuffer
const fileData = await resourceMgr.getMediaContent($r('app.media.imagetransfer'))
const buffer = fileData.buffer
// 创建imageSource
const imageSource = image.createImageSource(buffer)
// 获取PixelMap
const pixelMap = await imageSource.createPixelMap()
return pixelMap
}
...
}

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...
@State src:PixelMap = undefined
...
// 页面加载前将获取到的图片PixelMap数据赋值给状态变量src
async aboutToAppear() {
this.src = await this.getPixelMap()
}
...
// 创建ImagePacker实例
let imagePackerApi = image.createImagePacker();
let options = {
// 设置重新打包的图片格式
format: 'image/jpeg',
quality: 98
};
// 打包时传入图片的PixelMap：src和图片打包选项：option，异步获取打包后的数据data
imagePackerApi.packing(this.src, options).then((data) => {
console.log('Succeeded in packing the image.');
}).catch(error => {
console.log('Failed to pack the image..');
....
})

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...
// 打包时传入图片的pixelmap：src和图片打包选项：option，异步获取打包后的数据data
imagePackerApi.packing(this.src, options).then((data) => {
// 创建文件管理器保存选项实例
let photoSaveOptions = new picker.PhotoSaveOptions();
// 保存文件名（可选）
photoSaveOptions.newFileNames = ["imageTransfer.jpg"];
let photoViewPicker = new picker.PhotoViewPicker();
// 保存时传入保存的文件名：photoSaveOptions
photoViewPicker.save(photoSaveOptions)
.then((photoSaveResult) => {
setTimeout(() => {
// 获取到保存文件的URI，后续进行文件读取等操作
this.uri = photoSaveResult[0];
fs.open(this.uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE).then((file) => {
// 将图片打包数据data写入保存的文件
fs.write(file.fd, data).then((number) => {
console.info("foo imagetest: write data to file succeed and size is:" + number);
}).catch((err) => {
console.info("foo imagetest: write data to file failed with error:" + err);
});
// 完成文件写入后，关闭文件
fs.close(file, (err) => {
if (err) {
console.info("close file failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("close file success");
}
});
}).catch((err) => {
console.info("foo open file failed with error message: " + err.message + ", error code: " + err.code);
});
}, 200)
})
.catch((err) => {
console.error('PhotoViewPicker.save failed with err: ' + err);
})
})
...

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import image from '@ohos.multimedia.image';
import fs from '@ohos.file.fs';
import common from '@ohos.app.ability.common';
import picker from '@ohos.file.picker';
@Entry
@Component
struct Index {
@State src:PixelMap = undefined
context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext
private uri = null
// 页面加载前将获取到的图片PixelMap数据赋值给状态变量src
async aboutToAppear() {
this.src = await this.getPixelMap()
}
async getPixelMap(){
// 获取resourceManager资源管理
const resourceMgr = this.context.resourceManager
// 获取rawfile文件夹下httpimage.PNG的ArrayBuffer
const fileData = await resourceMgr.getMediaContent($r('app.media.contact6'))
const buffer = fileData.buffer
// 创建imageSource
const imageSource = image.createImageSource(buffer)
// 创建PixelMap
const pixelMap = await imageSource.createPixelMap()
return pixelMap
console.log('pixelMap ' + JSON.stringify(this.src.getPixelBytesNumber()))
}
build() {
Row() {
Column() {
Button('转换图片格式：png->jpeg')
.onClick(() => {
// 创建ImagePacker实例
let imagePackerApi = image.createImagePacker();
// 设置重新打包的图片格式，及图片压缩质量
let options = {
format: 'image/jpeg',
quality: 98
};
// 打包时传入图片的pixelmap：src和图片打包选项：option，异步获取打包后的数据data
imagePackerApi.packing(this.src, options).then((data) => {
// 创建文件管理器保存选项实例
let photoSaveOptions = new picker.PhotoSaveOptions();
// 保存文件名（可选）
photoSaveOptions.newFileNames = ["imageTransfer.jpg"];
let photoViewPicker = new picker.PhotoViewPicker();
// 保存时传入保存的文件名：photoSaveOptions
photoViewPicker.save(photoSaveOptions)
.then((photoSaveResult) => {
console.log('foo start')
setTimeout(() => {
// 获取到图片的URI后进行文件读取等操作
this.uri = photoSaveResult[0];
fs.open(this.uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE).then((file) => {
// 将图片打包数据data写入保存的文件
fs.write(file.fd, data).then((number) => {
console.info("foo imagetest: write data to file succeed and size is:" + number);
}).catch((err) => {
console.info("foo imagetest: write data to file failed with error:" + err);
});
// 完成文件写入后，关闭文件
fs.close(file, (err) => {
if (err) {
console.info("close file failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("close file success");
}
});
}).catch((err) => {
console.info("foo open file failed with error message: " + err.message + ", error code: " + err.code);
});
}, 200)
})
.catch((err) => {
console.error('PhotoViewPicker.save failed with err: ' + err);
})
})
})
}
.width('100%')
}
.height('100%')
}
}

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