提交 21ddaa83 编写于 作者: X xiaok 提交者: wangxiaokai

Add media image dev docs.

Signed-off-by: Nxiaok <wangxiaokai1@huawei.com>
上级 79190412
...@@ -10,3 +10,5 @@ ...@@ -10,3 +10,5 @@
- [视频播放开发指导](video-playback.md) - [视频播放开发指导](video-playback.md)
- [视频录制开发指导](video-recorder.md) - [视频录制开发指导](video-recorder.md)
- 图片
- [图片开发指导](image.md)
# 图片开发指导
## 场景介绍
图片开发的主要工作是将获取到的图片进行解码,将解码后的pixelmap编码成支持的格式,本文将对图片的解码、编码等场景开发进行介绍说明。
## 接口说明
详细API含义请参考[js-apis-image.md](https://gitee.com/openharmony/docs/blob/791904121afc0b9887510a6ec0504a23a71e6a3c/zh-cn/application-dev/reference/apis/js-apis-image.md)
## 开发步骤
### 全流程场景
包含流程:创建实例,读取图片信息,读写pixelmap,更新数据,打包像素,释放资源等流程。
```js
const Color = new ArrayBuffer(96);//用于存放图像像素数据
let opts = { alphaType: 0, editable: true, pixelFormat: 4, scaleMode: 1, size: { height: 2, width: 3 } } //图像像素数据
//创建pixelmap对象
const Color = new ArrayBuffer(96);
let opts = { alphaType: 0, editable: true, pixelFormat: 4, scaleMode: 1, size: { height: 2, width: 3 } }
image.createPixelMap(Color, opts, pixelmap => {
expect(pixelmap !== null).assertTrue();
console.info('TC_001-1 success');
done();
})
//用于读像素
pixelmap.readPixels(area,(data) => {
if(data !== null) {
var bufferArr = new Uint8Array(area.pixels);
var res = true;
for (var i = 0; i < bufferArr.length; i++) {
console.info('TC_021-1 buffer ' + bufferArr[i]);
if(res) {
if(bufferArr[i] == 0) {
res = false;
console.info('TC_021-1 Success');
expect(true).assertTrue();
done();
break;
}
}
}
//用于存像素
const readBuffer = new ArrayBuffer(96);
pixelmap.readPixelsToBuffer(readBuffer,() => {
var bufferArr = new Uint8Array(readBuffer);
var res = true;
for (var i = 0; i < bufferArr.length; i++) {
if(res) {
if (bufferArr[i] !== 0) {
res = false;
console.info('TC_020-1 Success');
expect(true).assertTrue();
done();
break;
}
}
}
//用于写像素
pixelmap.writePixels(area,() => {
const readArea = { pixels: new ArrayBuffer(20), offset: 0, stride: 8, region: { size: { height: 1, width: 2 }, x: 0, y: 0 }}
pixelmap.readPixels(readArea,() => {
var readArr = new Uint8Array(readArea.pixels);
var res = true;
for (var i = 0; i < readArr.length; i++) {
if(res) {
if (readArr[i] !== 0) {
res = false;
console.info('TC_022-1 Success');
expect(true).assertTrue();
done();
break;
}
}
}
//用于写像素到缓冲区
pixelmap.writeBufferToPixels(writeColor).then(() => {
const readBuffer = new ArrayBuffer(96);
pixelmap.readPixelsToBuffer(readBuffer).then (() => {
var bufferArr = new Uint8Array(readBuffer);
var res = true;
for (var i = 0; i < bufferArr.length; i++) {
if(res) {
if (bufferArr[i] !== i) {
res = false;
console.info('TC_023 Success');
expect(true).assertTrue()
done();
break;
}
}
}
//用于获取图片信息
pixelmap.getImageInfo( imageInfo => {
if (imageInfo !== null) {
console.info('TC_024-1 imageInfo is ready');
expect(imageInfo.size.height == 4).assertTrue();
expect(imageInfo.size.width == 6).assertTrue();
expect(imageInfo.pixelFormat == 4).assertTrue();
done();
}
})
//用于释放pixelmap
pixelmap.release(()=>{
expect(true).assertTrue();
console.log('TC_027-1 suc');
done();
})
//用于创建imagesource(uri)
const imageSourceApi = image.createImageSource(path);//'/data/local/tmp/test.jpg'
//用于创建imagesource(fd)
const imageSourceApi = image.createImageSource(29);
//用于创建imagesource(data)
const data = new ArrayBuffer(96);
const imageSourceApi = image.createImageSource(data);
//用于释放imagesource
imageSourceApi.release(() => {
console.info('TC_044-1 Success');
})
//用于编码
const imagePackerApi = image.createImagePacker();
imagePackerApi.packing(imageSourceApi, packOpts, data => {
console.info('TC_062-1 finished');
expect(data !== null).assertTrue();
done();
})
//用于释放imagepacker
imagePackerApi.release();
```
### 解码场景
```js
/data/local/tmp/test.jpg //设置创建imagesource的路径
//用路径创建imagesource
const imageSourceApi = image.createImageSource(path);//'/data/local/tmp/test.jpg'
//设置参数
let decodingOptions = {
sampleSize:1,//缩略图采样大小
editable: true, //是否可编辑
desiredSize:{ width:1, height:2},//期望输出大小
rotateDegrees:10,//旋转角度
desiredPixelFormat:2,//解码的像素格式
desiredRegion: { size: { height: 1, width: 2 }, x: 0, y: 0 },//解码的区域
index:0//图片序号
};
//用于回调方式创建pixelmap
imageSourceApi.createPixelMap(decodingOptions, pixelmap => {
console.info('TC_050 createPixelMap ');
expect(pixelmap !== null ).assertTrue();
done();
})
}
//用于promise创建pixelmap
imageSourceApi.createPixelMap().then(pixelmap => {
console.info('TC_050-11 createPixelMap ');
expect(pixelmap !== null ).assertTrue();
done();
})
//函数调用发生异常时,捕捉错误信息
catch(error => {
console.log('TC_050-11 error: ' + error);
expect().assertFail();
done();
})
//用于获取像素每行字节数
pixelmap.getBytesNumberPerRow( num => {
console.info('TC_025-1 num is ' + num);
expect(num == expectNum).assertTrue();
done();
})
//用于获取像素总字节数
pixelmap.getPixelBytesNumber(num => {
console.info('TC_026-1 num is ' + num);
expect(num == expectNum).assertTrue();
done();
})
//用于获取pixelmap信息
pixelmap.getImageInfo( imageInfo => {})
//用于打印获取失败信息
console.info('TC_024-1 imageInfo is empty');
expect(false).assertTrue()
//用于释放pixelmap
pixelmap.release(()=>{
expect(true).assertTrue();
console.log('TC_027-1 suc');
done();
})
//用于捕捉释放失败信息
catch(error => {
console.log('TC_027-1 error: ' + error);
expect().assertFail();
done();
})
```
### 编码场景
```js
/data/local/tmp/test.png //设置创建imagesource的路径
//用于设置imagesource
const imageSourceApi = image.createImageSource(path);//'/data/local/tmp/test.png'
//如果创建imagesource失败,打印错误信息
if (imageSourceApi == null) {
console.info('TC_062 create image source failed');
expect(false).assertTrue();
done();
}
//如果创建imagesource成功,则创建imagepacker
const imagePackerApi = image.createImagePacker();
//如果创建失败,打印错误信息
if (imagePackerApi == null) {
console.info('TC_062 create image packer failed');
expect(false).assertTrue();
done();
}
//如果创建imagepacker成功,则设置编码参数
let packOpts = { format:["image/jpeg"], //支持编码的格式为jpg
quality:98 }//图片质量0-100
//用于编码
imagePackerApi.packing(imageSourceApi, packOpts)
.then( data => {
console.info('TC_062 finished');
expect(data !== null).assertTrue();
done();
})
//编码完成,释放imagepacker
imagePackerApi.release();
//用于获取imagesource信息
imageSourceApi.getImageInfo(imageInfo => {
console.info('TC_045 imageInfo');
expect(imageInfo !== null).assertTrue();
done();
})
//用于更新增量数据
imageSourceIncrementalSApi.updateData(array, false, 0, 10,(error,data )=> {})
```
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