Collect Formatted Cell Ranges Without ScRangeList::Join
The API method getUniqueCellFormatRanges is used to collect ranges with equal cell formats, in order to generate automatic styles only once for each set of formats. The implementation uses ScAttrRectIterator to iterate over cell attributes, and ScRangeList::Join to update the list of ranges for each format. ScAttrRectIterator returns ranges column-wise. It that is taken into account, they can be joined more efficiently than with the general-case ScRangeList::Join method. In cases where a set of attributes is used in many non-adjacent cells or ranges, ScRangeList::Join can use a large part of the total saving time, so in these cases saving will be much faster.