Author: Peter Below

How to check if a printer supports postscript?

Answer:

That is really difficult do to if it has to work on all Windows platforms. The best 
way (no kidding) may be to ask the user which printer to use. What platforms do you 
need to support? If it is only Win2K (and perhaps XP) one may be able to use this 
(i have no postscript-enabled printer around to see if it works!): 

1   uses
2     WinSpool, Printers;
3   
4   {: Check if the currently selected printer supports postscript.
5     Only applicable on Win2K/XP! }
6   
7   function PrinterSupportsPostscript: Boolean;
8   const
9     POSTSCRIPT_PASSTHROUGH = 4115;
10    POSTSCRIPT_IDENTIFY = 4117;
11  
12    Escapes: array[0..2] of Cardinal =
13    (POSTSCRIPT_DATA, POSTSCRIPT_IDENTIFY, POSTSCRIPT_PASSTHROUGH);
14  var
15    res: Integer;
16    i: Integer;
17  begin
18    Result := false;
19    for i := Low(Escapes) to High(Escapes) do
20    begin
21      res := ExtEscape(printer.Handle,
22        QUERYESCSUPPORT,
23        sizeof(Escapes[0]),
24        @Escapes[i], 0, nil);
25      if res <> 0 then
26      begin
27        Result := true;
28        Break;
29      end;
30    end;
31  end;
32  
33  procedure TForm1.Button1Click(Sender: TObject);
34  const
35    boolstr: array[Boolean] of string = (' not', '');
36  var
37    i: Integer;
38    S: string;
39  begin
40    for i := 0 to Printer.Printers.Count - 1 do
41    begin
42      Printer.PrinterIndex := i;
43      memo1.Lines.add(
44        Format('Printer %s does%s support Postscript',
45        [printer.printers[printer.printerindex],
46        boolstr[PrinterSupportsPostscript]]));
47    end;
48  end;