nc-photos/app/lib/pixel_image_provider.dart

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

import 'package:flutter/foundation.dart';
import 'package:flutter/rendering.dart';

/// ImageProvider for raw RGBA pixels
class PixelImage extends ImageProvider<PixelImage> {
  PixelImage(
    this.rgba,
    this.width,
    this.height, {
    this.scale = 1.0,
  });

  @override
  obtainKey(ImageConfiguration configuration) =>
      SynchronousFuture<PixelImage>(this);

  @override
  load(PixelImage key, DecoderCallback decode) =>
      OneFrameImageStreamCompleter(_createImageInfo());

  Future<ImageInfo> _createImageInfo() async {
    final codec = await ImageDescriptor.raw(
      await ImmutableBuffer.fromUint8List(rgba),
      width: width,
      height: height,
      pixelFormat: PixelFormat.rgba8888,
    ).instantiateCodec();
    final frame = await codec.getNextFrame();
    return ImageInfo(image: frame.image, scale: scale);
  }

  final Uint8List rgba;
  final int width;
  final int height;

  /// The scale to place in the [ImageInfo] object of the image.
  final double scale;
}