generate static method

Future<String> generate(String root, String path, { NormalMapOptions options = const NormalMapOptions(), })

Makes the normal map of the image at path (project-relative) under root, beside it — <name>_normal.png, _2 and on when that is taken — and gives its path.

Throws an ArgumentError for a path outside the project — absolute, or climbing out with .. (a path read from a scene may) — or in a package (packages/<name>/…, the package's own): nothing is written there. The pixels are worked out off the UI's isolate.

Implementation

static Future<String> generate(
  String root,
  String path, {
  NormalMapOptions options = const NormalMapOptions(),
}) async {
  if (!ProjectFiles.isContained(path)) {
    throw ArgumentError.value(
      path,
      'path',
      'is outside the project: no normal map is made beside it',
    );
  }
  if (PackageAssetPaths.isPackageKey(path)) {
    throw ArgumentError.value(
      path,
      'path',
      "is a package's: no normal map is made in it",
    );
  }
  final picture = await Pixels.read('$root/$path');
  final map = await compute(_make, (picture, options));
  final dot = path.lastIndexOf('.');
  final stem = dot <= path.lastIndexOf('/') ? path : path.substring(0, dot);
  var n = 1;
  String out() => '${stem}_normal${n == 1 ? '' : '_$n'}.png';
  while (File('$root/${out()}').existsSync()) {
    n++;
  }
  final made = out();
  await map.writePng('$root/$made');
  return made;
}