Writing a raw string of data to the printer

Question:

How do I write a raw string of a data to the printer?

Answer:

Under Win16, you can use the SpoolFile function, or the Passthrough escape if the printer supports it. This is detailed in TI3196 - Direct Commands to Printer - Passthrough/Escape available from the Borland web site. Under Win32, you should use WritePrinter.

The following is an example of opening a printer and writing a raw string of data to the printer. Note that you must send the correct printer name, such as "HP LaserJet 5MP" for the function to succeed.

You are also responsible for embedding any necessary control codes that the printer may require.

uses WinSpool;

procedure WriteRawStringToPrinter(PrinterName:String; S:String);

var

Handle: THandle;

N: DWORD;

DocInfo1: TDocInfo1;

begin

if not OpenPrinter(PChar(PrinterName), Handle, nil) then

begin

ShowMessage('error ' + IntToStr(GetLastError));

Exit;

end;

with DocInfo1 do begin

pDocName := PChar('test doc');

pOutputFile := nil;

pDataType := 'RAW';

end;

StartDocPrinter(Handle, 1, @DocInfo1);

StartPagePrinter(Handle);

WritePrinter(Handle, PChar(S), Length(S), N);

EndPagePrinter(Handle);

EndDocPrinter(Handle);

ClosePrinter(Handle);

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

WriteRawStringToPrinter('HP', 'Test This');

end;