我有以下代码段，将图像数据提取到from(dateQuery.first()).pipe(
// TAP because it seems to be a sideeffect. If this could stop your stream, "filter" would be appropriate
tap(result =>query.greaterThanOrEqualTo('createdAt', result.createdAt)),
// MAP because we can discard "result" and only need the Moment-Object in the rest of the stream
map(result => getMoment(result.createdAt),
// switchMap to switch to the second stream, because it is only one command (in a long pipe) you don´t need a explicit return-command
switchMap( createdAt =>
from(query.find()).pipe(
// MAP because we now want a UserObjects-Array in our stream
map(el => createUserObjects(el)),
// MAP because we want our NamesUpdateList. Depending on the usage you may not need "Observable.of()" here
map(userObjects => createNamesUpdateList(userObjects, createdAt ))
)
)
).subscribe(
(next) => res.send(serialize(next)),
(error) => res.send(serialize(error)),
() => console.log('completed')
)
getMoment(date){
return moment(result.createdAt).format('DD/MM/YYYY - HH:mm:ss')
}
createUserObjects(el){
el.map((e) => {
return {
id: e.id,
username: e.get('username')
}
}
}
createNamesUpdateList(array, dateFormat){
return {
names: array,
lastUpdate: dateFormat
}
}
对象中，然后绘制一个圆。之后，我尝试将处理后的数据放回Mat数组中。该文件已保存，但是当我随后打开它时，收到消息，提示它无法打开。
byte[]如Micka所建议，可能可以使用imwrite。但是，如果要在捕获图像之前在屏幕上显示经过处理的图像怎么办？然后，我必须将已处理的private static class ImageSaver implements Runnable {
/**
* The JPEG image
*/
private final Image mImage;
private final File mFile;
ImageSaver(Image image, File file){
mImage = image;
mFile = file;
}
@Override
public void run(){
ByteBuffer buffer = mImage.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.remaining()];
buffer.get(bytes);
Mat mat = Imgcodecs.imdecode(new MatOfByte(bytes), Imgcodecs.CV_LOAD_IMAGE_UNCHANGED);
Point pt = new Point(mat.width()/2, mat.height()/2);
int radius = 40;
Scalar color = new Scalar(256,0,0);
Imgproc.circle(mat, pt, radius, color);
int length = (int) (mat.total() * mat.elemSize());
byte[] newBytes = new byte[length];
mat.get(0,0,newBytes);
FileOutputStream output = null;
try {
output = new FileOutputStream(mFile);
output.write(newBytes);
} catch (IOException e){
e.printStackTrace();
} finally {
mImage.close();
if (output != null){
try {
output.close();
} catch (IOException e){
e.printStackTrace();
}
}
}
}
}
复制到bytes吗？
我想改用本机，因为这看起来更快，分辨率更高。
答案 0 :(得分：0)
好的，所以我找到了自己的问题的答案。首先，如果保存图像是唯一的目标，那么使用imwrite确实是最简单的解决方案。
一种替代方法是使用
MatOfByte mByte = new MatOfByte();
Imgcodecs.imencode(".jpeg", mat, mByte);
...
output.write(mByte.toArray());
...