decodeImagePure function

Future<Rgba8Image> decodeImagePure(Uint8List encoded)

Decodes encoded into straight RGBA8 pixels with no Flutter SDK and no dart:ui behind it — mcp-04n: the headless half of flutter3d_core's own ImageDecoder typedef, which this function's signature already matches structurally without needing to import it (flutter3d_formats sits below flutter3d_core in the dependency order, so the import would run backwards).

PNG and baseline JPEG only, the same two formats sniffImageMimeType recognises a decoder for. Anything else — an unrecognised signature, a progressive JPEG decodeJpeg refuses, a truncated file — throws an ImageFormatException saying which; the texture upload that takes an ImageDecoder treats a throw as it treats a null, as no texture.

Implementation

Future<Rgba8Image> decodeImagePure(Uint8List encoded) async {
  final mimeType = sniffImageMimeType(encoded);
  final decoded = switch (mimeType) {
    'image/png' => decodePng(encoded),
    'image/jpeg' => decodeJpeg(encoded),
    _ => throw ImageFormatException(
      'an image this decoder does not read: PNG and baseline JPEG are, and '
      'this is ${mimeType ?? 'neither'}',
    ),
  };
  return Rgba8Image(
    width: decoded.width,
    height: decoded.height,
    pixels: decoded.rgba,
  );
}