fis_lib_vid/lib/processors/processor.dart

import 'dart:typed_data';

class Test {
  void run() {
    final processor = BrightnessProcessor();
    processor.propertyChanged.add(onPropertyChanged);
    processor.brightness++;
    processor.propertyChanged.remove(onPropertyChanged);
    processor.brightness++;
  }

  onPropertyChanged(Object sender, void e) {
    //
    print('onPropertyChanged');
  }
}

abstract class IImageProcessor {
  // final propertyChanged = FEventHandler<int>();
  late final FEventHandler<void> propertyChanged;

  bool get changed;

  Uint8List process(Uint8List pixelDatas);

  void reset();
}

class BrightnessProcessor implements IImageProcessor {
  int _brightness = 0;

  int get brightness => _brightness;

  set brightness(int value) {
    if (_brightness != value) {
      _brightness = value;

      // OnBrightnessChanged();
      onPropertyChanged();
    }
  }

  @override
  bool get changed => _brightness != 0;

  @override
  Uint8List process(Uint8List pixelDatas) {
    if (brightness == 0) {
      return pixelDatas;
    }
    int bVal = brightness;
    if (bVal < -255) bVal = -255;
    if (bVal > 255) bVal = 255;
    for (int i = 0; i < pixelDatas.length - 1; i += 4) {
      int b = pixelDatas[i];
      int g = pixelDatas[i + 1];
      int r = pixelDatas[i + 2];
      b += bVal;
      g += bVal;
      r += bVal;

      if (b < 0) b = 0;
      if (b > 255) b = 255;
      if (g < 0) g = 0;
      if (g > 255) g = 255;
      if (r < 0) r = 0;
      if (r > 255) r = 255;
      pixelDatas[i] = b;
      pixelDatas[i + 1] = g;
      pixelDatas[i + 2] = r;
    }
    // for (int i = 0; i < pixelDatas.length - 1; i++) {
    //   int pixel = pixelDatas[i];

    //   List<int> pixelBytes = intToBytes(pixel);
    //   int b = pixelBytes[0];
    //   int g = pixelBytes[1];
    //   int r = pixelBytes[2];
    //   b += bVal;
    //   g += bVal;
    //   r += bVal;

    //   if (b < 0) b = 0;
    //   if (b > 255) b = 255;
    //   if (g < 0) g = 0;
    //   if (g > 255) g = 255;
    //   if (r < 0) r = 0;
    //   if (r > 255) r = 255;
    //   pixelBytes[0] = b;
    //   pixelBytes[1] = g;
    //   pixelBytes[2] = r;
    //   ByteData data = ByteData.view(Uint8List.fromList(pixelBytes).buffer);
    //   final rst = data.getInt32(0, Endian.host);
    //   // final rst = bytesToInt(pixelBytes);
    //   pixelDatas[i] = rst;
    // }
    return pixelDatas;
  }

  static List<int> intToBytes(int i) {
    final bytes = List<int>.filled(4, 0, growable: false);
    bytes[0] = i & 0xff;
    bytes[1] = (i >> 8) & 0xff;
    bytes[2] = (i >> 16) & 0xff;
    bytes[3] = (i >> 24) & 0xff;
    return bytes;
  }

  static int bytesToInt(List<int> bytes, [int offset = 0]) {
    int value;
    value = (bytes[offset] & 0xff) |
        ((bytes[offset + 1] & 0xff) << 8) |
        ((bytes[offset + 2] & 0xff) << 16) |
        ((bytes[offset + 3] & 0xff) << 24);
    return value;
  }

  @override
  void reset() {
    print('reset');
  }

  @override
  FEventHandler<void> propertyChanged = FEventHandler<void>();

  void onPropertyChanged() {
    propertyChanged.emit(this, null);
  }
}

typedef FEventCallback<T> = void Function(
  Object sender,
  T e,
);

class FEventHandler<T> {
  List<FEventCallback<T>>? _callbacks;

  void emit(Object sender, T e) {
    if (_callbacks != null && _callbacks!.isNotEmpty) {
      for (final callback in _callbacks!) {
        callback.call(sender, e);
      }
    }
  }

  void add(FEventCallback<T> callback) {
    _callbacks ??= [];
    _callbacks!.add(callback);
  }

  void remove(FEventCallback<T> callback) {
    if (_callbacks == null) return;

    if (_callbacks!.contains(callback)) {
      _callbacks!.remove(callback);
    }
  }
}