如何将Flutter CameraImage从图像流转换为base64编码的二进制数据对象开发者社区

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// Take the picutre
await _cameraController.takePicture(path);
// Load it from my filesystem
File imagefile = new File(path); 
// Convert to amazon requirements
List imageBytes = imagefile.readAsBytesSync();
String base64Image = base64Encode(imageBytes);

final int numBytes =
    image.planes.fold(0, (count, plane) => count += plane.bytes.length);
final Uint8List allBytes = Uint8List(numBytes);
int nextIndex = 0;
for (int i = 0; i < image.planes.length; i++) {
  allBytes.setRange(nextIndex, nextIndex + image.planes[i].bytes.length,
      image.planes[i].bytes);
  nextIndex += image.planes[i].bytes.length;
// Convert as done previously
String base64Image = base64Encode(allBytes);

Future convertYUV420toImageColor(CameraImage image) async {
  try {
    final int width = image.width;
    final int height = image.height;
    final int uvRowStride = image.planes[1].bytesPerRow;
    final int uvPixelStride = image.planes[1].bytesPerPixel;
    print("uvRowStride: " + uvRowStride.toString());
    print("uvPixelStride: " + uvPixelStride.toString());
    // imgLib -> Image package from https://pub.dartlang.org/packages/image
    var img = imglib.Image(width, height); // Create Image buffer
    // Fill image buffer with plane[0] from YUV420_888
    for(int x=0; x < width; x++) {
      for(int y=0; y < height; y++) {
        final int uvIndex = uvPixelStride * (x/2).floor() + uvRowStride*(y/2).floor();
        final int index = y * width + x;
        final yp = image.planes[0].bytes[index];
        final up = image.planes[1].bytes[uvIndex];
        final vp = image.planes[2].bytes[uvIndex];
        // Calculate pixel color
        int r = (yp + vp * 1436 / 1024 - 179).round().clamp(0, 255);
        int g = (yp - up * 46549 / 131072 + 44 -vp * 93604 / 131072 + 91).round().clamp(0, 255);
        int b = (yp + up * 1814 / 1024 - 227).round().clamp(0, 255);     
        // color: 0x FF  FF  FF  FF 
        //           A   B   G   R
        img.data[index] = (0xFF << 24) | (b << 16) | (g << 8) | r;
    imglib.PngEncoder pngEncoder = new imglib.PngEncoder(level: 0, filter: 0);
    List png = pngEncoder.encodeImage(img);
    muteYUVProcessing = false;
    return Image.memory(png);  
  } catch (e) {
    print(">>>>>>>>>>>> ERROR:" + e.toString());
  return null;
}

// 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;
}

Future> convertImagetoPng(CameraImage image) async {
  try {
    imglib.Image img;
    if (image.format.group == ImageFormatGroup.yuv420) {
      img = convertYUV420_ToPNG(image);
    } else if (image.format.group == ImageFormatGroup.bgra8888) {
      img = convertBGRA8888_ToPNG(image);
    imglib.PngEncoder pngEncoder = new imglib.PngEncoder();
    // Convert to png
    List png = pngEncoder.encodeImage(img);

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