1. override
RectCallback getRectCallback(RenderBox referenceBox)

The rectangle to use for the highlight effect and for clipping the splash effects if containedInkWell is true.

This method is intended to be overridden by descendants that specialize InkResponse for unusual cases. For example, TableRowInkWell implements this method to return the rectangle corresponding to the row that the widget is in.

The default behavior returns null, which is equivalent to returning the referenceBox argument's bounding box (though slightly more efficient).

Source 

@override
RectCallback getRectCallback(RenderBox referenceBox) {
  return () {
    RenderObject cell = referenceBox;
    AbstractNode table = cell.parent;
    Matrix4 transform = new Matrix4.identity();
    while (table is RenderObject && table is! RenderTable) {
      RenderTable parentBox = table;
      parentBox.applyPaintTransform(cell, transform);
      assert(table == cell.parent);
      cell = table;
      table = table.parent;
    }
    if (table is RenderTable) {
      TableCellParentData cellParentData = cell.parentData;
      assert(cellParentData.y != null);
      Rect rect = table.getRowBox(cellParentData.y);
      // The rect is in the table's coordinate space. We need to change it to the
      // TableRowInkWell's coordinate space.
      table.applyPaintTransform(cell, transform);
      Offset offset = MatrixUtils.getAsTranslation(transform);
      if (offset != null)
        return rect.shift(-offset);
    }
    return Rect.zero;
  };
}