How to use DeviceCapabilities to Retrieve the paper names and sizes from specific printer in Delphi

Question

I have been looking for a way of retrieving the papers supported by an specific printer and their sizes (width and height) in millimeters if possible.

I have seen and "Studied" many posts and sites about using Printer.Getprinter and Printer.SetPrinter but I am really far from understanding the whole process to make that work, I learnt that I have to use DeviceCapabilities in order to retrieve data that is specific to one printer but I really don't know how to use those structures. I need something similar to this but for a specific printer and using the DeviceCapabilities. I use Delphi VCL.

In the question linked, they use EnumForms which I understand is for all the printers, they also mention that DeviceCapabilities is for a specific printer, and that is what I need, to get the supported paper names and sizes but only for the selected printer and not all of them. lets say I select my printer: Printer.PrinterIndex:= Printer.Printers.IndexOf(MyPrinter); I would like to get the papers and paper sizes for those supported by that printer.

Thank you so much for any help provided!

Answer 1

Here is an example that calls DeviceCapabilities for the currently selected printer and outputs supported paper names for "the current default initialization values for the specified printer driver" to a memo. The quoted part in the previous sentence is from the documentation of the function and I'm not absolutely positive that I understand what it means. That happens because a DevMode is not passed.

procedure TForm1.Button1Click(Sender: TObject);
var
  PrinterName: string;
  HPrinter: THandle;
  Ret: DWORD;
  Buf: array of array [0..63] of Char;
  i: Integer;
begin
  PrinterName := Printer.Printers[Printer.PrinterIndex];
  if OpenPrinter(PChar(PrinterName), HPrinter, nil) then begin
    Ret := DeviceCapabilities(PChar(PrinterName), nil, DC_PAPERNAMES, nil, nil);
    if Ret > 0 then begin
      SetLength(Buf, Ret);
      DeviceCapabilities(PChar(PrinterName), nil, DC_PAPERNAMES, Pointer(Buf), nil);
      for i := 0 to Ret - 1 do
        Memo1.Lines.Add(Buf[i]);
    end;
    ClosePrinter(HPrinter);
  end;
end;

Explaining the code is kind of pointless, I'd be duplicating the documentation. I included the link above.