英文:
How can I convert CameraImageStream CameraImage to jpeg or bitmap in Flutter using Flutter's image-processing libraries?
问题
I can help with the translation of the code you provided. Here's the translated code:
无法将CameraImage从bgra8888转换为jpeg。
我已经尝试了不同的方法，但都不起作用。
我最后尝试的是：
```dart
void testB(CameraImage i) async {
cameraRepository.stopRecording();
print(i.format.group);
imglib.Image im = imglib.Image.fromBytes(
width: (i.planes[0].bytesPerRow / 4).round(),
height: i.height,
bytes: (i.planes[0].bytes).buffer);
imglib.PngEncoder pngEncoder = new imglib.PngEncoder();
Uint8List png = pngEncoder.encode(im);
//Uint8List jpeg = imglib.encodeJpg(im);
imageList.add(png);
当我像这样在小部件中显示它：
return Scaffold(
appBar: AppBar(
title: const Text('Test'),
),
body: ListView.builder(
itemCount: 1,
itemBuilder: (BuildContext context, int index) {
return SizedBox(width:500, height:500, child: Container(
decoration: BoxDecoration(
image: new DecorationImage(fit: BoxFit.cover, image: MemoryImage(BlocProvider.of<CameraBloc>(context).imageList[0], scale: 0.5)),
)
));
}),
);
图像会显示出来，但是转换似乎有问题：
（这是我的键盘，所以图像不是完全的噪音）。
我尝试了这段代码：
import 'package:image/image.dart' as imglib;
import 'package:camera/camera.dart';
Future<List<int>> convertImagetoPng(CameraImage image) async {
try {
imglib.Image img;
if (image.format.group == ImageFormatGroup.yuv420) {
img = _convertYUV420(image);
} else if (image.format.group == ImageFormatGroup.bgra8888) {
img = _convertBGRA8888(image);
}
imglib.PngEncoder pngEncoder = new imglib.PngEncoder();
// 转换为png
List<int> png = pngEncoder.encodeImage(img);
return png;
} catch (e) {
print(">>>>>>>>>> ERROR:" + e.toString());
}
return null;
}
// CameraImage BGRA8888 -> PNG
// 颜色
imglib.Image _convertBGRA8888(CameraImage image) {
return imglib.Image.fromBytes(
image.width,
image.height,
image.planes[0].bytes,
format: imglib.Format.bgra,
);
}
// CameraImage YUV420_888 -> PNG -> Image（压缩：0，过滤器：无）
// 黑色
imglib.Image _convertYUV420(CameraImage image) {
var img = imglib.Image(image.width, image.height); // 创建图像缓冲区
Plane plane = image.planes[0];
const int shift = (0xFF << 24);
// 使用YUV420_888的plane[0]填充图像缓冲区
for (int x = 0; x < image.width; x++) {
for (int planeOffset = 0;
planeOffset < image.height * image.width;
planeOffset += image.width) {
final pixelColor = plane.bytes[planeOffset + x];
// 颜色：0x FF FF FF FF
// A B G R
// 计算像素颜色
var newVal = shift | (pixelColor << 16) | (pixelColor << 8) | pixelColor;
img.data[planeOffset + x] = newVal;
}
}
return img;
}
但似乎已经过时。尝试时出现不同的错误。
更新
imglib.Image im = imglib.Image.fromBytes(
width: (i.planes[0].bytesPerRow / 4).round(),
height: i.height,
bytes: (i.planes[0].bytes).buffer);
将高度更改为宽度，宽度更改为高度后，图像不会更清晰，几乎是好的。我搞混了这一点，因为看起来似乎不对。
但仍然不好。
Please note that the code comments have also been translated for your convenience.
<details>
<summary>英文:</summary>
I cant convert CameraImage from bgra8888 to an jpeg.
I have found different approaches but none of them work.
The last what I tried is:
void testB(CameraImage i) async {
cameraRepository.stopRecording();
print(i.format.group);
imglib.Image im = imglib.Image.fromBytes(
width: (i.planes[0].bytesPerRow / 4).round(),
height: i.height,
bytes: (i.planes[0].bytes).buffer);
imglib.PngEncoder pngEncoder = new imglib.PngEncoder();
Uint8List png = pngEncoder.encode(im);
//Uint8List jpeg = imglib.encodeJpg(im);
imageList.add(png);
When I display it in a widget like this:
return Scaffold(
appBar: AppBar(
title: const Text('Test'),
),
body: ListView.builder(
itemCount: 1,
itemBuilder: (BuildContext context, int index) {
return SizedBox(width:500, height:500, child: Container(
decoration: BoxDecoration(
image: new DecorationImage(fit: BoxFit.cover, image: MemoryImage(BlocProvider.of<CameraBloc>(context).imageList[0], scale: 0.5)),
)
));
}),
);
I images shows up, but something is wrong with the conversion:
https://pasteboard.co/5yMYpLFxsPkR.jpg
(Thats my Keyboard, so the image isnt complete Noise).
I've tried this code:
import 'package:image/image.dart' as imglib;
import 'package:camera/camera.dart';
Future<List<int>> convertImagetoPng(CameraImage image) async {
try {
imglib.Image img;
if (image.format.group == ImageFormatGroup.yuv420) {
img = _convertYUV420(image);
} else if (image.format.group == ImageFormatGroup.bgra8888) {
img = _convertBGRA8888(image);
}
imglib.PngEncoder pngEncoder = new imglib.PngEncoder();
// Convert to png
List<int> png = pngEncoder.encodeImage(img);
return png;
} catch (e) {
print(">>>>>>>>>>>> ERROR:" + e.toString());
}
return null;
}
// CameraImage BGRA8888 -> PNG
// Color
imglib.Image _convertBGRA8888(CameraImage image) {
return imglib.Image.fromBytes(
image.width,
image.height,
image.planes[0].bytes,
format: imglib.Format.bgra,
);
}
// CameraImage YUV420_888 -> PNG -> Image (compresion:0, filter: none)
// Black
imglib.Image _convertYUV420(CameraImage image) {
var img = imglib.Image(image.width, image.height); // Create Image buffer
Plane plane = image.planes[0];
const int shift = (0xFF << 24);
// Fill image buffer with plane[0] from YUV420_888
for (int x = 0; x < image.width; x++) {
for (int planeOffset = 0;
planeOffset < image.height * image.width;
planeOffset += image.width) {
final pixelColor = plane.bytes[planeOffset + x];
// color: 0x FF FF FF FF
// A B G R
// Calculate pixel color
var newVal = shift | (pixelColor << 16) | (pixelColor << 8) | pixelColor;
img.data[planeOffset + x] = newVal;
}
}
return img;
}
But it seems outdated. Got different errors when i tried it.
**UPDATE**
imglib.Image im = imglib.Image.fromBytes(
width: (i.planes[0].bytesPerRow / 4).round(),
height: i.height,
bytes: (i.planes[0].bytes).buffer);
After changing height to width and width to height, the image is no clearer and almost good. I confused this as it seems.
But its still not good.
</details>
# 答案1
**得分**: 1
如果有人在iPhone上将此流式相机图像（brga8888）转换时遇到困难，由于图像包的新版本，参数已更改：
```dart
imglib.Image im = imglib.Image.fromBytes(
height: i.height,
width: i.width,
bytes: (i.planes[0].bytes).buffer,
format: imglib.Format.uint8,
order: ChannelOrder.bgra
);
这将生成一个清晰的图像。
英文:
If someone is struggling to convert this Streaming CameraImage on IPhone (brga8888),
since a new Version of Image Package the Parameter have changed:
imglib.Image im = imglib.Image.fromBytes(
height: i.height,
width: i.width,
bytes: (i.planes[0].bytes).buffer,
format: imglib.Format.uint8,
order: ChannelOrder.bgra
);
This produced a clean Image.
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