This feature of ignoring empty rows is supported from version 19.1.
The code uses some of the objects defined in: Working with Common Operations.
Sometimes Excel document contains information at the beginning of the worksheet and after that, it contains some count of empty (blank) rows and information again e.g. summary row. Also, there is the possibility that the worksheet contains the empty columns as well. In case, if the number of empty rows or columns is considerably huge, the rendering time increases and hence, it affects the performance.
GroupDocs.Viewer for .NET provides the options, CellsOptions.setIgnoreEmptyRows(bool) which allow omitting to render empty rows as shown in the samples below.
Ignoring Empty Rows