網頁上的原始圖像使用正確的原點和色彩

import 'dart:typed_data';
import 'dart:ui' as ui;

// Parse `image` as a displayable image.
//
// Each byte in `image` is a pixel channel, in the order of blue, green, red,
// and alpha, starting from the bottom left corner and going row first.
Future<ui.Image> parseMyImage(Uint8List image, int width, int height) async {
  final ui.ImageDescriptor descriptor = ui.ImageDescriptor.raw(
    await ui.ImmutableBuffer.fromUint8List(image),
    width: width,
    height: height,
    pixelFormat: ui.PixelFormat.rgba8888,
  );
  return (await (await descriptor.instantiateCodec()).getNextFrame()).image;
}

import 'dart:typed_data';
import 'dart:ui' as ui;

Uint8List verticallyFlipImage(Uint8List sourceBytes, int width, int height) {
  final Uint32List source = Uint32List.sublistView(ByteData.sublistView(sourceBytes));
  final Uint32List result = Uint32List(source.length);
  int sourceOffset = 0;
  int resultOffset = 0;
  for (final int row = height - 1; row >= 0; row -= 1) {
    sourceOffset = width * row;
    for (final int col = 0; col < width; col += 1) {
      result[resultOffset] = source[sourceOffset];
      resultOffset += 1;
      sourceOffset += 1;
    }
  }
  return Uint8List.sublistView(ByteData.sublistView(sourceBytes))
}

Future<ui.Image> parseMyImage(Uint8List image, int width, int height) async {
  final Uint8List correctedImage = verticallyFlipImage(image, width, height);
  final ui.ImageDescriptor descriptor = ui.ImageDescriptor.raw(
    await ui.ImmutableBuffer.fromUint8List(correctedImage),
    width: width,
    height: height,
    pixelFormat: ui.PixelFormat.rgba8888,
  );
  return (await (await descriptor.instantiateCodec()).getNextFrame()).image;
}

Uint8List verticallyFlipImage(Uint8List sourceBytes, int width, int height) {
  // Same as the example above.
}

late Future<bool> imageRawUsesCorrectBehavior = (() async {
  final ui.ImageDescriptor descriptor = ui.ImageDescriptor.raw(
    await ui.ImmutableBuffer.fromUint8List(Uint8List.fromList(<int>[0xED, 0, 0, 0xFF])),
    width: 1, height: 1, pixelFormat: ui.PixelFormat.rgba8888);
  final ui.Image image = (await (await descriptor.instantiateCodec()).getNextFrame()).image;
  final Uint8List resultPixels = Uint8List.sublistView(
    (await image.toByteData(format: ui.ImageByteFormat.rawStraightRgba))!);
  return resultPixels[0] == 0xED;
})();

Future<ui.Image> parseMyImage(Uint8List image, int width, int height) async {
  final Uint8List correctedImage = (await imageRawUsesCorrectBehavior) ?
    verticallyFlipImage(image, width, height) : image;
  final ui.ImageDescriptor descriptor = ui.ImageDescriptor.raw(
    await ui.ImmutableBuffer.fromUint8List(correctedImage), // Use the corrected image
    width: width,
    height: height,
    pixelFormat: ui.PixelFormat.bgra8888, // Use the alternate format
  );
  return (await (await descriptor.instantiateCodec()).getNextFrame()).image;
}