oneAnchor2twoAnchor()
                
                oneAnchor2twoAnchor(\PHPExcel_Worksheet  $sheet, string  $coordinates, integer  $offsetX, integer  $offsetY, integer  $width, integer  $height) : array
                Convert 1-cell anchor coordinates to 2-cell anchor coordinates
This function is ported from PEAR Spreadsheet_Writer_Excel with small modifications
                Calculate the vertices that define the position of the image as required by
the OBJ record.
    +------------+------------+
    |     A      |      B     |
| +-----+------------+------------+ | 
 | 
(x1,y1) | 
 | 
 | 
1 | 
(A1).___ | 
__ | 
 | 
 | 
 | 
 | 
| +-----+---- | 
BITMAP | 
-----+ | 
 | 
 | 
 | 
 | 
| 2 | 
 | 
__. | 
 | 
 | 
(B2) | 
 | 
 | 
(x2,y2) | 
+---- +------------+------------+
Example of a bitmap that covers some of the area from cell A1 to cell B2.
Based on the width and height of the bitmap we need to calculate 8 vars:
$col_start, $row_start, $col_end, $row_end, $x1, $y1, $x2, $y2.
The width and height of the cells are also variable and have to be taken into
account.
The values of $col_start and $row_start are passed in from the calling
function. The values of $col_end and $row_end are calculated by subtracting
the width and height of the bitmap from the width and height of the
underlying cells.
The vertices are expressed as a percentage of the underlying cell width as
follows (rhs values are in pixels):
  x1 = X / W *1024
  y1 = Y / H *256
  x2 = (X-1) / W *1024
  y2 = (Y-1) / H *256
  Where:  X is distance from the left side of the underlying cell
          Y is distance from the top of the underlying cell
          W is the width of the cell
          H is the height of the cell
                                    Parameters
                    
                                                    
                                | \PHPExcel_Worksheet | 
                                $sheet  | 
                                 | 
                            
                                                    
                                | string | 
                                $coordinates  | 
                                E.g. 'A1'  | 
                            
                                                    
                                | integer | 
                                $offsetX  | 
                                Horizontal offset in pixels  | 
                            
                                                    
                                | integer | 
                                $offsetY  | 
                                Vertical offset in pixels  | 
                            
                                                    
                                | integer | 
                                $width  | 
                                Width in pixels  | 
                            
                                                    
                                | integer | 
                                $height  | 
                                Height in pixels  | 
                            
                                            
                
                
                                    Returns
                    array