spine-runtimes/spine-flutter/lib/raw_image_provider.dart

// MIT License
//
// Copyright (c) 2021 Yrom Wang
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
import 'dart:typed_data';
import 'dart:ui' as ui;

import 'package:flutter/foundation.dart';
import 'package:flutter/painting.dart';
import 'package:crypto/crypto.dart';

/// Decodes the given [image] (raw image pixel data) as an image ('dart:ui')
class RawImageProvider extends ImageProvider<_RawImageKey> {
  final RawImageData image;
  final double? scale;
  final int? targetWidth;
  final int? targetHeight;
  RawImageProvider(
    this.image, {
    this.scale = 1.0,
    this.targetWidth,
    this.targetHeight,
  });

  @override
  ImageStreamCompleter loadImage(_RawImageKey key, ImageDecoderCallback decode) {
    return MultiFrameImageStreamCompleter(
      codec: _loadAsync(key),
      scale: scale ?? 1.0,
      debugLabel: 'RawImageProvider(${describeIdentity(key)})',
    );
  }

  @override
  Future<_RawImageKey> obtainKey(ImageConfiguration configuration) {
    return SynchronousFuture(image._obtainKey());
  }

  /// see [ui.decodeImageFromPixels]
  Future<ui.Codec> _loadAsync(_RawImageKey key) async {
    assert(key == image._obtainKey());
    // rgba8888 pixels
    var buffer = await ui.ImmutableBuffer.fromUint8List(image.pixels);

    final descriptor = ui.ImageDescriptor.raw(
      buffer,
      width: image.width,
      height: image.height,
      pixelFormat: image.pixelFormat,
    );
    assert(() {
      debugPrint('ImageDescriptor: ${descriptor.width}x${descriptor.height}');
      return true;
    }());
    return descriptor.instantiateCodec(
        targetWidth: targetWidth, targetHeight: targetHeight);
  }
}

class _RawImageKey {
  final int w;
  final int h;
  final int format;
  final Digest dataHash;
  _RawImageKey(this.w, this.h, this.format, this.dataHash);

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) return true;

    return other is _RawImageKey &&
        other.w == w &&
        other.h == h &&
        other.format == format &&
        other.dataHash == dataHash;
  }

  @override
  int get hashCode {
    return Object.hash(w, h, format, dataHash.hashCode);
  }
}

/// Raw pixels data of an image
class RawImageData {
  final Uint8List pixels;
  final int width;
  final int height;
  final ui.PixelFormat pixelFormat;

  RawImageData(
    this.pixels,
    this.width,
    this.height, {
    this.pixelFormat = ui.PixelFormat.rgba8888,
  });

  _RawImageKey? _key;
  _RawImageKey _obtainKey() {
    return _key ??=
        _RawImageKey(width, height, pixelFormat.index, md5.convert(pixels));
  }
}