floodFill method

Future<void> floodFill(int x, int y)

Implementation

Future<void> floodFill(int x, int y) async {
  // Setup
  _prepare();
  // ***Do first call to floodfill.
  _linearFill(x, y);
  // ***Call floodfill routine while floodfill _ranges still exist on the
  // queue
  _FloodFillRange range;
  while (_ranges.isNotEmpty) {
    // **Get Next Range Off the Queue
    range = _ranges.removeFirst();
    // **Check Above and Below Each Pixel in the Floodfill Range
    int downPxIdx = (_width * (range.y + 1)) + range.startX;
    int upPxIdx = (_width * (range.y - 1)) + range.startX;
    int upY = range.y - 1; // so we can pass the y coord by ref
    int downY = range.y + 1;
    for (int i = range.startX; i <= range.endX; i++) {
      // *Start Fill Upwards
      // if we're not above the top of the bitmap and the pixel above
      // this one is within the color tolerance
      if (range.y > 0 && (!_pixelsChecked[upPxIdx]) && _checkPixel(i, upY)) {
        _linearFill(i, upY);
      }
      // *Start Fill Downwards
      // if we're not below the bottom of the bitmap and the pixel
      // below this one is within the color tolerance
      if (range.y < (_height - 1) &&
          (!_pixelsChecked[downPxIdx]) &&
          _checkPixel(i, downY)) {
        _linearFill(i, downY);
      }
      downPxIdx++;
      upPxIdx++;
    }
  }
}