Printer.GetPrinter vs. WinSpool.GetPrinter

what a different of Printer.GetPrinter and WinSpool.GetPrinter?

Printer.GetPrinter is part of the Delphi VCL, it gets you the *current* 
DEVMODE of the selected printer inside your application. The function 
happens to return a global memory handle for the devmode record instead of 
a pointer to it, so it has to be locked to get access to the memory of the 
record. When you modify the current Devmode settings and then call 
Printer.beginDoc the settings will be used to create the printer device 
context. It is not necessary to call Printer.SetPrinter to make the changes 
active. But any changes you make here are local to your program, they do 
not influence other programs printing to the same printer. 

WinSpool.GetPrinter is part of the Windows Spooler API, it gets you 
information about the *default* settings for the printer. As it happens the 
TPrinterInfo2 record contains a pointer to the DEVMODE holding the default 
settings, not a memory handle, so locking is not required. Changes you make 
to the default DEVMODE have no effect at all until you call 
Winspool.SetPrinter, passing it the TPrinterInfo2 record you obtained from 
Winspool.GetPrinter. The SetPrinter call changes the defaults, so this 
influences other programs that use the printer as well as yours.