Updating colors and shaders at runtime about vector_graphics

[aloisdeniel]

Here is an example of such a listener if FlutterVectorGraphicsListener would have a raw public constructor instead of _.

class OverridesFlutterVectorGraphicsListener
    extends FlutterVectorGraphicsListener {
  factory OverridesFlutterVectorGraphicsListener({
    required Map<int, int> colorOverrides,
    int id = 0,
    Locale? locale,
    TextDirection? textDirection,
    bool clipViewbox = true,
    @visibleForTesting
    DefaultPictureFactory pictureFactory = const DefaultPictureFactory(),
  }) {
    final PictureRecorder recorder = pictureFactory.createPictureRecorder();
    return OverridesFlutterVectorGraphicsListener.raw(
      id,
      pictureFactory,
      recorder,
      pictureFactory.createCanvas(recorder),
      locale,
      textDirection,
      clipViewbox,
      colorOverrides,
    );
  }

  OverridesFlutterVectorGraphicsListener.raw(
    int id,
    DefaultPictureFactory pictureFactory,
    PictureRecorder recorder,
    Canvas canvas,
    Locale? locale,
    TextDirection? textDirection,
    bool clipViewbox,
    this.colorOverrides,
  ) : super.raw(
          id,
          pictureFactory,
          recorder,
          canvas,
          locale,
          textDirection,
          clipViewbox,
        );

  final Map<int, int> colorOverrides;

  @override
  void onLinearGradient(
    double fromX,
    double fromY,
    double toX,
    double toY,
    Int32List colors,
    Float32List? offsets,
    int tileMode,
    int id,
  ) {
    final colorValues = <int>[];
    for (var color in colors) {
      final replacedColor = colorOverrides[_colorValue(color)];
      colorValues.add(replacedColor ?? color);
    }
    super.onLinearGradient(
      fromX,
      fromY,
      toX,
      toY,
      Int32List.fromList(colorValues),
      offsets,
      tileMode,
      id,
    );
  }

  @override
  void onPaintObject({
    required int color,
    required int? strokeCap,
    required int? strokeJoin,
    required int blendMode,
    required double? strokeMiterLimit,
    required double? strokeWidth,
    required int paintStyle,
    required int id,
    required int? shaderId,
  }) {
    /// If we add an override we add it to the paints instead

    final int? override = colorOverrides[_colorValue(color)];
    if (override != null) {
      return super.onPaintObject(
        id: id,
        color: override,
        strokeCap: strokeCap,
        strokeJoin: strokeJoin,
        blendMode: blendMode,
        strokeMiterLimit: strokeMiterLimit,
        strokeWidth: strokeWidth,
        paintStyle: paintStyle,
        shaderId: shaderId,
      );
    }

    return super.onPaintObject(
      id: id,
      color: color,
      strokeCap: strokeCap,
      strokeJoin: strokeJoin,
      blendMode: blendMode,
      strokeMiterLimit: strokeMiterLimit,
      strokeWidth: strokeWidth,
      paintStyle: paintStyle,
      shaderId: shaderId,
    );
  }

  final _colorData = ByteData(4);

  int _colorValue(int value) {
    _colorData.setInt32(0, value);
    return _colorData.getUint32(0);
  }
}