The EM_FORMATRANGE message formats a range of text in a rich edit control for a specific device.
EM_FORMATRANGE wParam = (WPARAM) (BOOL) fRender; lParam = (LPARAM) (FORMATRANGE FAR *) lpFmt;
This message is typically used with the EM_DISPLAYBAND message to format a rich edit control’s contents for an output device such as a printer.
It is very important to free cached information after the last time you use this message by specifying NULL in lpFmt. In addition, after using this message for one device, you must free cached information before using it again for a different device.
Returns the index of the last character that fits in the region plus one.