PHPOffice/PHPExcel — pull request #61 by sadapon2008 (2012-10-19 02:55:40+00:00)
Title: PHPExcel_Worksheet::copyCellStyle() method added to just copy cell's style to the others

Some style-related method seem to affect performance.
Probably, PHPExcel::getCellXfByHashCode method call in PHPExcel_Worksheet::duplicateStyle method cosumes too much time to find similar style from the array PHPExcel::_cellXfCollection especially in the case when the number of style objects is big.
Instead of using such methods, I recommend to just copy a cell's style with added PHPExcel_Worksheet::copyCellStyle() method.
The method receives PHPExcel_Cell object and ranges of cells,
and just copy the style of specified cell to the cells at specified ranges.
It makes faster than setting a style for each cell.