How to set the paper size using the WinSpool API? - delphi

Question

I can't use the XPS API since the program has to be able to print on Windows XP.
I'm trying to set the paper size from Letter to A4 using WinSpool.
This is my test code:
var
H : THandle;
I : TBytes;
Info : PPrinterInfo2;
NeededSize : DWORD;
DevMode : PDeviceMode;
PD : TPrinterDefaults;
begin
PD.pDatatype := nil;
PD.pDevMode := nil;
PD.DesiredAccess := PRINTER_ACCESS_ADMINISTER;
if not OpenPrinter('Brother HL-5350DN series Printer', H, #PD) then begin
raise Exception.Create('OpenPrinter error: ' + SysErrorMessage(GetLastError));
end;
try
Assert(not GetPrinter(H, 2, nil, 0, #NeededSize));
SetLength(I, NeededSize);
Info := #I[0];
if not GetPrinter(H, 2, Info, NeededSize, #NeededSize) then begin
raise Exception.Create('GetPrinter error: ' + SysErrorMessage(GetLastError));
end;
DevMode := Info.pDevMode;
DevMode.dmFields := DevMode.dmFields or DM_PAPERSIZE;
DevMode.dmPaperSize := DMPAPER_A4;
Info.pSecurityDescriptor := nil; // According to MSDN it has to be niled if we're not going to change it.
if not SetPrinter(H, 2, Info, 0) then begin
raise Exception.Create('SetPrinter error: ' + SysErrorMessage(GetLastError));
end;
finally
ClosePrinter(H);
end;
TPrintDialog.Create(Self).Execute; // This is just so I can check the paper size
end;
I have two problems related to access rights.
If I set PD.DesiredAccess to PRINTER_ACCESS_ADMINISTER the GetPrinter call fails, I guess this is due to UAC.
If I set it to PRINTER_ACCESS_USE the GetPrinter call succeeds and the Info structure is fine, but the call to SetPrinter fails.
Interestingly enough when I ignore the Result of SetPrinter the print dialog reports A4 as the printer size even though SetPrinter fails.
Am I doing it completly wrong and it is enough to pass a correctly setup up PDeviceMode to OpenPrinter? (I actually came up with this after writing this question :-)
Another question regarding the VCL:
If I use the Printers unit how do I know how big the buffers have to be that get passed as parameters to the TPrinter.GetPrinter method?
Background:
The system is: Windows 7 Professional 64-Bit English with English locale.
I'm trying to print to A4 paper on a network printer (Brother HL-5350DN).
I have set all printer settings in the control panel to A4 paper, but the Delphi 2009 program I'm writing still gets the paper dimensions for US Letter.
In other words: The Delphi program doesn't respect the default settings of the printer spooler.
If I run a TPrinterDialog first and select the correct paper size from there manually (in the advanced printer settings) everything is fine.
The program has to run without any UI, so I have to solve this programmatically or preferably the program should just respect the default Windows printer spooler settings.
Maybe I have missed some imporant setting?

Answer 1

try this guys
it work for me
uses WinSpool,Windows,System;
procedure SetPrinterInfo(APrinterName: PChar);
var
HPrinter : THandle;
InfoSize,
BytesNeeded: Cardinal;
DevMode : PDeviceMode;
PI2: PPrinterInfo2;
PrinterDefaults: TPrinterDefaults;
begin
with PrinterDefaults do
begin
DesiredAccess := PRINTER_ACCESS_USE;
pDatatype := nil;
pDevMode := nil;
end;
if OpenPrinter(APrinterName, HPrinter, #PrinterDefaults) then
try
SetLastError(0);
//Determine the number of bytes to allocate for the PRINTER_INFO_2 construct...
if not GetPrinter(HPrinter, 2, nil, 0, #BytesNeeded) then
begin
//Allocate memory space for the PRINTER_INFO_2 pointer (PrinterInfo2)...
PI2 := AllocMem(BytesNeeded);
try
InfoSize := SizeOf(TPrinterInfo2);
if GetPrinter(HPrinter, 2, PI2, BytesNeeded, #BytesNeeded) then
begin
DevMode := PI2.pDevMode;
DevMode.dmFields := DevMode.dmFields or DM_PAPERSIZE;
DevMode.dmPaperSize := DMPAPER_A4;
PI2.pSecurityDescriptor := nil;
// Apply settings to the printer
if DocumentProperties(0, hPrinter, APrinterName, PI2.pDevMode^,
PI2.pDevMode^, DM_IN_BUFFER or DM_OUT_BUFFER) = IDOK then
begin
SetPrinter(HPrinter, 2, PI2, 0); // Ignore the result of this call...
end;
end;
finally
FreeMem(PI2, BytesNeeded);
end;
end;
finally
ClosePrinter(HPrinter);
end;
end;

Answer 2

Like David wrote, my specific problem is solved by setting the correct printer preferences in Windows.
I still haven't found a way to set the local printing properties for my application, but that is no longer necessary.
Like Sertac wrote you can read and write the global printer preferences using TPrinter.GetPrinter and TPrinter.SetPrinter. (See the comments to the question)
Since nobody provided an anwser and the problem is now solved, I'm marking this as community wiki. Feel free to improve this answer.