count method

int count(
  1. Rectangle area
)

Implementation

int count(Rectangle area) {
  final clipped = _clipRect(area);
  if (clipped.isEmpty) return 0;
  final stride = width + 1;
  final x0 = clipped.minX;
  final y0 = clipped.minY;
  final x1 = clipped.maxX;
  final y1 = clipped.maxY;
  return _prefixSums[y1 * stride + x1] -
      _prefixSums[y0 * stride + x1] -
      _prefixSums[y1 * stride + x0] +
      _prefixSums[y0 * stride + x0];
}