Check if a printer supports postscript

Problem/Question/Abstract:

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!):

uses
WinSpool, Printers;

{: Check if the currently selected printer supports postscript.
Only applicable on Win2K/XP! }

function PrinterSupportsPostscript: Boolean;
const
POSTSCRIPT_PASSTHROUGH = 4115;
POSTSCRIPT_IDENTIFY = 4117;

Escapes: array[0..2] of Cardinal =
(POSTSCRIPT_DATA, POSTSCRIPT_IDENTIFY, POSTSCRIPT_PASSTHROUGH);
var
res: Integer;
i: Integer;
begin
Result := false;
for i := Low(Escapes) to High(Escapes) do
begin
res := ExtEscape(printer.Handle,
QUERYESCSUPPORT,
sizeof(Escapes[0]),
@Escapes[i], 0, nil);
if res <> 0 then
begin
Result := true;
Break;
end;
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
const
boolstr: array[Boolean] of string = (' not', '');
var
i: Integer;
S: string;
begin
for i := 0 to Printer.Printers.Count - 1 do
begin
Printer.PrinterIndex := i;
memo1.Lines.add(
Format('Printer %s does%s support Postscript',
[printer.printers[printer.printerindex],
boolstr[PrinterSupportsPostscript]]));
end;
end;