// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// For documentation see https://github.com/flutter/engine/blob/main/lib/ui/painting.dart
part of ui;

// ignore: unused_element, Used in Shader assert.
bool _offsetIsValid(Offset offset) {
  assert(!offset.dx.isNaN && !offset.dy.isNaN, 'Offset argument contained a NaN value.');
  return true;
}

// ignore: unused_element, Used in Shader assert.
bool _matrix4IsValid(Float32List matrix4) {
  assert(matrix4.length == 16, 'Matrix4 must have 16 entries.');
  return true;
}

void _validateColorStops(List<Color> colors, List<double>? colorStops) {
  if (colorStops == null) {
    if (colors.length != 2) {
      throw ArgumentError('"colors" must have length 2 if "colorStops" is omitted.');
    }
  } else {
    if (colors.length != colorStops.length) {
      throw ArgumentError('"colors" and "colorStops" arguments must have equal length.');
    }
  }
}

Color _scaleAlpha(Color a, double factor) {
  return a.withAlpha(engine.clampInt((a.alpha * factor).round(), 0, 255));
}

class Color {
  const Color(int value) : value = value & 0xFFFFFFFF;
  const Color.fromARGB(int a, int r, int g, int b)
      : value = (((a & 0xff) << 24) |
                ((r & 0xff) << 16) |
                ((g & 0xff) << 8) |
                ((b & 0xff) << 0)) &
            0xFFFFFFFF;
  const Color.fromRGBO(int r, int g, int b, double opacity)
      : value = ((((opacity * 0xff ~/ 1) & 0xff) << 24) |
                ((r & 0xff) << 16) |
                ((g & 0xff) << 8) |
                ((b & 0xff) << 0)) &
            0xFFFFFFFF;
  final int value;
  int get alpha => (0xff000000 & value) >> 24;
  double get opacity => alpha / 0xFF;
  int get red => (0x00ff0000 & value) >> 16;
  int get green => (0x0000ff00 & value) >> 8;
  int get blue => (0x000000ff & value) >> 0;
  Color withAlpha(int a) {
    return Color.fromARGB(a, red, green, blue);
  }

  Color withOpacity(double opacity) {
    assert(opacity >= 0.0 && opacity <= 1.0);
    return withAlpha((255.0 * opacity).round());
  }

  Color withRed(int r) {
    return Color.fromARGB(alpha, r, green, blue);
  }

  Color withGreen(int g) {
    return Color.fromARGB(alpha, red, g, blue);
  }

  Color withBlue(int b) {
    return Color.fromARGB(alpha, red, green, b);
  }

  // See <https://www.w3.org/TR/WCAG20/#relativeluminancedef>
  static double _linearizeColorComponent(double component) {
    if (component <= 0.03928) {
      return component / 12.92;
    }
    return math.pow((component + 0.055) / 1.055, 2.4) as double;
  }

  double computeLuminance() {
    // See <https://www.w3.org/TR/WCAG20/#relativeluminancedef>
    final double R = _linearizeColorComponent(red / 0xFF);
    final double G = _linearizeColorComponent(green / 0xFF);
    final double B = _linearizeColorComponent(blue / 0xFF);
    return 0.2126 * R + 0.7152 * G + 0.0722 * B;
  }

  static Color? lerp(Color? a, Color? b, double t) {
    if (b == null) {
      if (a == null) {
        return null;
      } else {
        return _scaleAlpha(a, 1.0 - t);
      }
    } else {
      if (a == null) {
        return _scaleAlpha(b, t);
      } else {
        return Color.fromARGB(
          engine.clampInt(_lerpInt(a.alpha, b.alpha, t).toInt(), 0, 255),
          engine.clampInt(_lerpInt(a.red, b.red, t).toInt(), 0, 255),
          engine.clampInt(_lerpInt(a.green, b.green, t).toInt(), 0, 255),
          engine.clampInt(_lerpInt(a.blue, b.blue, t).toInt(), 0, 255),
        );
      }
    }
  }

  static Color alphaBlend(Color foreground, Color background) {
    final int alpha = foreground.alpha;
    if (alpha == 0x00) {
      // Foreground completely transparent.
      return background;
    }
    final int invAlpha = 0xff - alpha;
    int backAlpha = background.alpha;
    if (backAlpha == 0xff) {
      // Opaque background case
      return Color.fromARGB(
        0xff,
        (alpha * foreground.red + invAlpha * background.red) ~/ 0xff,
        (alpha * foreground.green + invAlpha * background.green) ~/ 0xff,
        (alpha * foreground.blue + invAlpha * background.blue) ~/ 0xff,
      );
    } else {
      // General case
      backAlpha = (backAlpha * invAlpha) ~/ 0xff;
      final int outAlpha = alpha + backAlpha;
      assert(outAlpha != 0x00);
      return Color.fromARGB(
        outAlpha,
        (foreground.red * alpha + background.red * backAlpha) ~/ outAlpha,
        (foreground.green * alpha + background.green * backAlpha) ~/ outAlpha,
        (foreground.blue * alpha + background.blue * backAlpha) ~/ outAlpha,
      );
    }
  }

  static int getAlphaFromOpacity(double opacity) {
    return (clampDouble(opacity, 0.0, 1.0) * 255).round();
  }

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) {
      return true;
    }
    if (other.runtimeType != runtimeType) {
      return false;
    }
    return other is Color && other.value == value;
  }

  @override
  int get hashCode => value.hashCode;

  @override
  String toString() {
    return 'Color(0x${value.toRadixString(16).padLeft(8, '0')})';
  }
}

enum StrokeCap {
  butt,
  round,
  square,
}

// These enum values must be kept in sync with SkPaint::Join.
enum StrokeJoin {
  miter,
  round,
  bevel,
}

enum PaintingStyle {
  fill,
  stroke,
}

enum BlendMode {
  // This list comes from Skia's SkXfermode.h and the values (order) should be
  // kept in sync.
  // See: https://skia.org/user/api/skpaint#SkXfermode
  clear,
  src,
  dst,
  srcOver,
  dstOver,
  srcIn,
  dstIn,
  srcOut,
  dstOut,
  srcATop,
  dstATop,
  xor,
  plus,
  modulate,

  // Following blend modes are defined in the CSS Compositing standard.
  screen, // The last coeff mode.
  overlay,
  darken,
  lighten,
  colorDodge,
  colorBurn,
  hardLight,
  softLight,
  difference,
  exclusion,
  multiply, // The last separable mode.
  hue,
  saturation,
  color,
  luminosity,
}

enum Clip {
  none,
  hardEdge,
  antiAlias,
  antiAliasWithSaveLayer,
}

abstract class Paint {
  factory Paint() => engine.renderer.createPaint();
  static bool enableDithering = false;
  BlendMode get blendMode;
  set blendMode(BlendMode value);
  PaintingStyle get style;
  set style(PaintingStyle value);
  double get strokeWidth;
  set strokeWidth(double value);
  StrokeCap get strokeCap;
  set strokeCap(StrokeCap value);
  StrokeJoin get strokeJoin;
  set strokeJoin(StrokeJoin value);
  bool get isAntiAlias;
  set isAntiAlias(bool value);

  Color get color;
  set color(Color value);
  bool get invertColors;

  set invertColors(bool value);
  Shader? get shader;
  set shader(Shader? value);
  MaskFilter? get maskFilter;
  set maskFilter(MaskFilter? value);
  // TODO(ianh): verify that the image drawing methods actually respect this
  FilterQuality get filterQuality;
  set filterQuality(FilterQuality value);
  ColorFilter? get colorFilter;
  set colorFilter(ColorFilter? value);

  double get strokeMiterLimit;
  set strokeMiterLimit(double value);
  ImageFilter? get imageFilter;
  set imageFilter(ImageFilter? value);
}

abstract class Shader {
  Shader._();

  void dispose();

  bool get debugDisposed;
}

abstract class Gradient extends Shader {
  factory Gradient.linear(
    Offset from,
    Offset to,
    List<Color> colors, [
    List<double>? colorStops,
    TileMode tileMode = TileMode.clamp,
    Float64List? matrix4,
  ]) {
    final Float32List? matrix = matrix4 == null ? null : engine.toMatrix32(matrix4);
    return engine.renderer.createLinearGradient(
      from,
      to,
      colors,
      colorStops,
      tileMode,
      matrix);
  }

  factory Gradient.radial(
    Offset center,
    double radius,
    List<Color> colors, [
    List<double>? colorStops,
    TileMode tileMode = TileMode.clamp,
    Float64List? matrix4,
    Offset? focal,
    double focalRadius = 0.0,
  ]) {
    _validateColorStops(colors, colorStops);
    // If focal is null or focal radius is null, this should be treated as a regular radial gradient
    // If focal == center and the focal radius is 0.0, it's still a regular radial gradient
    final Float32List? matrix32 = matrix4 != null ? engine.toMatrix32(matrix4) : null;
    if (focal == null || (focal == center && focalRadius == 0.0)) {
      return engine.renderer.createRadialGradient(
        center, radius, colors, colorStops, tileMode, matrix32);
    } else {
      assert(center != Offset.zero ||
          focal != Offset.zero); // will result in exception(s) in Skia side
      return engine.renderer.createConicalGradient(
        focal, focalRadius, center, radius, colors, colorStops, tileMode, matrix32);
    }
  }
  factory Gradient.sweep(
    Offset center,
    List<Color> colors, [
    List<double>? colorStops,
    TileMode tileMode = TileMode.clamp,
    double startAngle = 0.0,
    double endAngle = math.pi * 2,
    Float64List? matrix4,
  ]) => engine.renderer.createSweepGradient(
    center,
    colors,
    colorStops,
    tileMode,
    startAngle,
    endAngle,
    matrix4 != null ? engine.toMatrix32(matrix4) : null);
}

typedef ImageEventCallback = void Function(Image image);

abstract class Image {
  static ImageEventCallback? onCreate;
  static ImageEventCallback? onDispose;

  int get width;
  int get height;
  Future<ByteData?> toByteData({ImageByteFormat format = ImageByteFormat.rawRgba});
  void dispose();
  bool get debugDisposed;

  Image clone() => this;

  bool isCloneOf(Image other) => other == this;

  List<StackTrace>? debugGetOpenHandleStackTraces() => null;

  ColorSpace get colorSpace => ColorSpace.sRGB;

  @override
  String toString() => '[$width\u00D7$height]';
}

class ColorFilter implements ImageFilter {
  const factory ColorFilter.mode(Color color, BlendMode blendMode) = engine.EngineColorFilter.mode;
  const factory ColorFilter.matrix(List<double> matrix) = engine.EngineColorFilter.matrix;
  const factory ColorFilter.linearToSrgbGamma() = engine.EngineColorFilter.linearToSrgbGamma;
  const factory ColorFilter.srgbToLinearGamma() = engine.EngineColorFilter.srgbToLinearGamma;
}

// These enum values must be kept in sync with SkBlurStyle.
enum BlurStyle {
  // These mirror SkBlurStyle and must be kept in sync.
  normal,
  solid,
  outer,
  inner,
}

class MaskFilter {
  const MaskFilter.blur(
    this._style,
    this._sigma,
  );

  final BlurStyle _style;
  final double _sigma;
  double get webOnlySigma => _sigma;
  BlurStyle get webOnlyBlurStyle => _style;

  @override
  bool operator ==(Object other) {
    return other is MaskFilter
        && other._style == _style
        && other._sigma == _sigma;
  }

  @override
  int get hashCode => Object.hash(_style, _sigma);

  @override
  String toString() => 'MaskFilter.blur($_style, ${_sigma.toStringAsFixed(1)})';
}

enum FilterQuality {
  none,
  low,
  medium,
  high,
}

class ImageFilter {
  factory ImageFilter.blur({
    double sigmaX = 0.0,
    double sigmaY = 0.0,
    TileMode tileMode = TileMode.clamp
  }) => engine.renderer.createBlurImageFilter(
    sigmaX: sigmaX,
    sigmaY: sigmaY,
    tileMode: tileMode
  );

  factory ImageFilter.dilate({ double radiusX = 0.0, double radiusY = 0.0 }) =>
    engine.renderer.createDilateImageFilter(radiusX: radiusX, radiusY: radiusY);

  factory ImageFilter.erode({ double radiusX = 0.0, double radiusY = 0.0 }) =>
    engine.renderer.createErodeImageFilter(radiusX: radiusX, radiusY: radiusY);

  factory ImageFilter.matrix(Float64List matrix4, {FilterQuality filterQuality = FilterQuality.low}) {
    if (matrix4.length != 16) {
      throw ArgumentError('"matrix4" must have 16 entries.');
    }
    return engine.renderer.createMatrixImageFilter(matrix4, filterQuality: filterQuality);
  }

  factory ImageFilter.compose({required ImageFilter outer, required ImageFilter inner}) =>
    engine.renderer.composeImageFilters(outer: outer, inner: inner);
}

enum ColorSpace {
  sRGB,
  extendedSRGB,
}

enum ImageByteFormat {
  rawRgba,
  rawStraightRgba,
  rawUnmodified,
  png,
}

enum PixelFormat {
  rgba8888,
  bgra8888,
}

typedef ImageDecoderCallback = void Function(Image result);

abstract class FrameInfo {
  FrameInfo._();
  Duration get duration => Duration(milliseconds: _durationMillis);
  int get _durationMillis => 0;
  Image get image;
}

class Codec {
  Codec._();
  int get frameCount => 0;
  int get repetitionCount => 0;
  Future<FrameInfo> getNextFrame() {
    return engine.futurize<FrameInfo>(_getNextFrame);
  }

  String? _getNextFrame(engine.Callback<FrameInfo> callback) => null;
  void dispose() {}
}

Future<Codec> instantiateImageCodec(
  Uint8List list, {
  int? targetWidth,
  int? targetHeight,
  bool allowUpscaling = true,
}) => engine.renderer.instantiateImageCodec(
  list,
  targetWidth: targetWidth,
  targetHeight: targetHeight,
  allowUpscaling: allowUpscaling);

Future<Codec> instantiateImageCodecFromBuffer(
  ImmutableBuffer buffer, {
  int? targetWidth,
  int? targetHeight,
  bool allowUpscaling = true,
}) => engine.renderer.instantiateImageCodec(
  buffer._list!,
  targetWidth: targetWidth,
  targetHeight: targetHeight,
  allowUpscaling: allowUpscaling);

Future<Codec> instantiateImageCodecWithSize(
  ImmutableBuffer buffer, {
  TargetImageSizeCallback? getTargetSize,
}) async {
  if (getTargetSize == null) {
    return engine.renderer.instantiateImageCodec(buffer._list!);
  } else {
    final Codec codec = await engine.renderer.instantiateImageCodec(buffer._list!);
    try {
      final FrameInfo info = await codec.getNextFrame();
      try {
        final int width = info.image.width;
        final int height = info.image.height;
        final TargetImageSize targetSize = getTargetSize(width, height);
        return engine.renderer.instantiateImageCodec(buffer._list!,
            targetWidth: targetSize.width, targetHeight: targetSize.height, allowUpscaling: false);
      } finally {
        info.image.dispose();
      }
    } finally {
      codec.dispose();
    }
  }
}

typedef TargetImageSizeCallback = TargetImageSize Function(int intrinsicWidth, int intrinsicHeight);

class TargetImageSize {
  const TargetImageSize({this.width, this.height})
      : assert(width == null || width > 0),
        assert(height == null || height > 0);

  final int? width;
  final int? height;
}

Future<Codec> webOnlyInstantiateImageCodecFromUrl(Uri uri,
  {engine.WebOnlyImageCodecChunkCallback? chunkCallback}) =>
  engine.renderer.instantiateImageCodecFromUrl(uri, chunkCallback: chunkCallback);

void decodeImageFromList(Uint8List list, ImageDecoderCallback callback) {
  _decodeImageFromListAsync(list, callback);
}

Future<void> _decodeImageFromListAsync(Uint8List list, ImageDecoderCallback callback) async {
  final Codec codec = await instantiateImageCodec(list);
  final FrameInfo frameInfo = await codec.getNextFrame();
  callback(frameInfo.image);
}

// Encodes the input pixels into a BMP file that supports transparency.
//
// The `pixels` should be the scanlined raw pixels, 4 bytes per pixel, from left
// to right, then from top to down. The order of the 4 bytes of pixels is
// decided by `format`.
Future<Codec> createBmp(
  Uint8List pixels,
  int width,
  int height,
  int rowBytes,
  PixelFormat format,
) {
  late bool swapRedBlue;
  switch (format) {
    case PixelFormat.bgra8888:
      swapRedBlue = true;
      break;
    case PixelFormat.rgba8888:
      swapRedBlue = false;
      break;
  }

  // See https://en.wikipedia.org/wiki/BMP_file_format for format examples.
  // The header is in the 108-byte BITMAPV4HEADER format, or as called by
  // Chromium, WindowsV4. Do not use the 56-byte or 52-byte Adobe formats, since
  // they're not supported.
  const int dibSize = 0x6C /* 108: BITMAPV4HEADER */;
  const int headerSize = dibSize + 0x0E;
  final int bufferSize = headerSize + (width * height * 4);
  final ByteData bmpData = ByteData(bufferSize);
  // 'BM' header
  bmpData.setUint16(0x00, 0x424D);
  // Size of data
  bmpData.setUint32(0x02, bufferSize, Endian.little);
  // Offset where pixel array begins
  bmpData.setUint32(0x0A, headerSize, Endian.little);
  // Bytes in DIB header
  bmpData.setUint32(0x0E, dibSize, Endian.little);
  // Width
  bmpData.setUint32(0x12, width, Endian.little);
  // Height
  bmpData.setUint32(0x16, height, Endian.little);
  // Color panes (always 1)
  bmpData.setUint16(0x1A, 0x01, Endian.little);
  // bpp: 32
  bmpData.setUint16(0x1C, 32, Endian.little);
  // Compression method is BITFIELDS to enable bit fields
  bmpData.setUint32(0x1E, 3, Endian.little);
  // Raw bitmap data size
  bmpData.setUint32(0x22, width * height, Endian.little);
  // Print DPI width
  bmpData.setUint32(0x26, width, Endian.little);
  // Print DPI height
  bmpData.setUint32(0x2A, height, Endian.little);
  // Colors in the palette
  bmpData.setUint32(0x2E, 0x00, Endian.little);
  // Important colors
  bmpData.setUint32(0x32, 0x00, Endian.little);
  // Bitmask R
  bmpData.setUint32(0x36, swapRedBlue ? 0x00FF0000 : 0x000000FF, Endian.little);
  // Bitmask G
  bmpData.setUint32(0x3A, 0x0000FF00, Endian.little);
  // Bitmask B
  bmpData.setUint32(0x3E, swapRedBlue ? 0x000000FF : 0x00FF0000, Endian.little);
  // Bitmask A
  bmpData.setUint32(0x42, 0xFF000000, Endian.little);

  int destinationByte = headerSize;
  final Uint32List combinedPixels = Uint32List.sublistView(pixels);
  // BMP is scanlined from bottom to top. Rearrange here.
  for (int rowCount = height - 1; rowCount >= 0; rowCount -= 1) {
    int sourcePixel = rowCount * rowBytes;
    for (int colCount = 0; colCount < width; colCount += 1) {
      bmpData.setUint32(destinationByte, combinedPixels[sourcePixel], Endian.little);
      destinationByte += 4;
      sourcePixel += 1;
    }
  }

  return instantiateImageCodec(
    bmpData.buffer.asUint8List(),
  );
}

void decodeImageFromPixels(
  Uint8List pixels,
  int width,
  int height,
  PixelFormat format,
  ImageDecoderCallback callback, {
  int? rowBytes,
  int? targetWidth,
  int? targetHeight,
  bool allowUpscaling = true,
}) => engine.renderer.decodeImageFromPixels(
  pixels,
  width,
  height,
  format,
  callback,
  rowBytes: rowBytes,
  targetWidth: targetWidth,
  targetHeight: targetHeight,
  allowUpscaling: allowUpscaling);

class Shadow {
  const Shadow({
    this.color = const Color(_kColorDefault),
    this.offset = Offset.zero,
    this.blurRadius = 0.0,
  })  : assert(blurRadius >= 0.0, 'Text shadow blur radius should be non-negative.');

  static const int _kColorDefault = 0xFF000000;
  final Color color;
  final Offset offset;
  final double blurRadius;
  // See SkBlurMask::ConvertRadiusToSigma().
  // <https://github.com/google/skia/blob/bb5b77db51d2e149ee66db284903572a5aac09be/src/effects/SkBlurMask.cpp#L23>
  static double convertRadiusToSigma(double radius) {
    return radius > 0 ? radius * 0.57735 + 0.5 : 0;
  }

  double get blurSigma => convertRadiusToSigma(blurRadius);
  Paint toPaint() {
    return Paint()
      ..color = color
      ..maskFilter = MaskFilter.blur(BlurStyle.normal, blurSigma);
  }

  Shadow scale(double factor) {
    return Shadow(
      color: color,
      offset: offset * factor,
      blurRadius: blurRadius * factor,
    );
  }

  static Shadow? lerp(Shadow? a, Shadow? b, double t) {
    if (b == null) {
      if (a == null) {
        return null;
      } else {
        return a.scale(1.0 - t);
      }
    } else {
      if (a == null) {
        return b.scale(t);
      } else {
        return Shadow(
          color: Color.lerp(a.color, b.color, t)!,
          offset: Offset.lerp(a.offset, b.offset, t)!,
          blurRadius: _lerpDouble(a.blurRadius, b.blurRadius, t),
        );
      }
    }
  }

  static List<Shadow>? lerpList(List<Shadow>? a, List<Shadow>? b, double t) {
    if (a == null && b == null) {
      return null;
    }
    a ??= <Shadow>[];
    b ??= <Shadow>[];
    final List<Shadow> result = <Shadow>[];
    final int commonLength = math.min(a.length, b.length);
    for (int i = 0; i < commonLength; i += 1) {
      result.add(Shadow.lerp(a[i], b[i], t)!);
    }
    for (int i = commonLength; i < a.length; i += 1) {
      result.add(a[i].scale(1.0 - t));
    }
    for (int i = commonLength; i < b.length; i += 1) {
      result.add(b[i].scale(t));
    }
    return result;
  }

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) {
      return true;
    }
    return other is Shadow &&
        other.color == color &&
        other.offset == offset &&
        other.blurRadius == blurRadius;
  }

  @override
  int get hashCode => Object.hash(color, offset, blurRadius);

  @override
  String toString() => 'TextShadow($color, $offset, $blurRadius)';
}

abstract class ImageShader extends Shader {
  factory ImageShader(Image image, TileMode tmx, TileMode tmy, Float64List matrix4, {
    FilterQuality? filterQuality,
  }) => engine.renderer.createImageShader(image, tmx, tmy, matrix4, filterQuality);

  @override
  void dispose();

  @override
  bool get debugDisposed;
}

class ImmutableBuffer {
  ImmutableBuffer._(this._length);
  static Future<ImmutableBuffer> fromUint8List(Uint8List list) async {
    final ImmutableBuffer instance = ImmutableBuffer._(list.length);
    instance._list = list;
    return instance;
  }

  static Future<ImmutableBuffer> fromAsset(String assetKey) async {
    throw UnsupportedError('ImmutableBuffer.fromAsset is not supported on the web.');
  }

  static Future<ImmutableBuffer> fromFilePath(String path) async {
    throw UnsupportedError('ImmutableBuffer.fromFilePath is not supported on the web.');
  }

  Uint8List? _list;

  int get length => _length;
  final int _length;

  bool get debugDisposed {
    late bool disposed;
    assert(() {
      disposed = _list == null;
      return true;
    }());
    return disposed;
  }
  void dispose() => _list = null;
}

class ImageDescriptor {
  // Not async because there's no expensive work to do here.
  ImageDescriptor.raw(
    ImmutableBuffer buffer, {
    required int width,
    required int height,
    int? rowBytes,
    required PixelFormat pixelFormat,
  })   : _width = width,
        _height = height,
        _rowBytes = rowBytes,
        _format = pixelFormat {
    _data = buffer._list;
  }

  ImageDescriptor._()
      : _width = null,
        _height = null,
        _rowBytes = null,
        _format = null;

  static Future<ImageDescriptor> encoded(ImmutableBuffer buffer) async {
    final ImageDescriptor descriptor = ImageDescriptor._();
    descriptor._data = buffer._list;
    return descriptor;
  }

  Uint8List? _data;
  final int? _width;
  final int? _height;
  final int? _rowBytes;
  final PixelFormat? _format;

  Never _throw(String parameter) {
    throw UnsupportedError('ImageDescriptor.$parameter is not supported on web.');
  }

  int get width => _width ?? _throw('width');
  int get height => _height ?? _throw('height');
  int get bytesPerPixel =>
      throw UnsupportedError('ImageDescriptor.bytesPerPixel is not supported on web.');
  void dispose() => _data = null;
  Future<Codec> instantiateCodec({int? targetWidth, int? targetHeight}) async {
    if (_data == null) {
      throw StateError('Object is disposed');
    }
    if (_width == null) {
      return instantiateImageCodec(
        _data!,
        targetWidth: targetWidth,
        targetHeight: targetHeight,
        allowUpscaling: false,
      );
    }

    return createBmp(_data!, width, height, _rowBytes ?? width, _format!);
  }
}

abstract class FragmentProgram {
  static Future<FragmentProgram> fromAsset(String assetKey) {
    return engine.renderer.createFragmentProgram(assetKey);
  }

  FragmentShader fragmentShader();
}

abstract class FragmentShader implements Shader {
  void setFloat(int index, double value);

  void setImageSampler(int index, Image image);

  @override
  void dispose();

  @override
  bool get debugDisposed;
}