dilateArtifact function

Artifact dilateArtifact({ required Artifact matrixImage, required int kernelSize, })

Applies dilation morphological operation to a binary image.

Dilation expands the white regions in a binary image, which helps connect nearby text elements and fill small gaps in characters.

Implementation

Artifact dilateArtifact({
  required final Artifact matrixImage,
  required int kernelSize,
}) {
  final Artifact result = Artifact(matrixImage.cols, matrixImage.rows);
  final int halfKernel = kernelSize ~/ 2;
  final int width = matrixImage.cols;
  final int height = matrixImage.rows;

  // Pre-compute row boundaries for each y position
  final List<int> minKYs = List<int>.filled(height, 0);
  final List<int> maxKYs = List<int>.filled(height, 0);
  for (int y = 0; y < height; y++) {
    minKYs[y] = max(0, y - halfKernel);
    maxKYs[y] = min(height - 1, y + halfKernel);
  }

  // Pre-compute column boundaries for each x position
  final List<int> minKXs = List<int>.filled(width, 0);
  final List<int> maxKXs = List<int>.filled(width, 0);
  for (int x = 0; x < width; x++) {
    minKXs[x] = max(0, x - halfKernel);
    maxKXs[x] = min(width - 1, x + halfKernel);
  }

  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      if (matrixImage.cellGet(x, y)) {
        for (int ky = minKYs[y]; ky <= maxKYs[y]; ky++) {
          for (int kx = minKXs[x]; kx <= maxKXs[x]; kx++) {
            result.cellSet(kx, ky, true);
          }
        }
      }
    }
  }

  return result;
}