{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  SysUtils,
  WinSpool,
  Windows,
  Messages,
  Classes;
var
  hPrinter: THandle;

{$R *.res}
Function GetDefaultPrinterName():PChar; //得到默認的打印機名稱
var
  sIniFile, sSection, sKeyName,p,q: PChar;
begin
  sIniFile := 'win.ini';
  sSection := 'windows';
  sKeyName := 'device';
  p:=StrAlloc(80);
  q:=StrAlloc(80);
  GetPrivateProfileString(sSection,sKeyName,nil,p,80,sIniFile); 
  StrLCopy(q,p,(strscan(p,',')-p));
  Result := q;
end;

Function addpage():Boolean; //添加一打印紙張類型名稱為300k
var
  FormInfo: TFormInfo1;
  PaperSize: TSize;
  PaperRect: TRect;
begin
  FormInfo.Flags := FORM_USER;
  FormInfo.pName := PChar('300k');
  PaperSize.cx := 100000;
  PaperSize.cy := 100000; //300k紙張的默認大小 1000mm*1000mm
  PaperRect.Left := 1;
  PaperRect.Top := 1;
  PaperRect.Right := 100000;
  PaperRect.Bottom := 100000; //紙張的邊距
  FormInfo.Size := PaperSize;
  FormInfo.ImageableArea := PaperRect;
  AddForm(hPrinter, 1, @FormInfo);
  Result := True;
end;

Function changepape():Boolean; //改變當前的打印紙張設置
var
  FormInfos : Array [1..1024] of Form_Info_1;
  cbNeeded, cReturned ,neededsize: DWord;
  i,j:integer;
  ppo:PRINTER_INFO_2;
  dev :PDeviceMode;
begin
  EnumForms(hPrinter, 1, Nil, 0, cbNeeded, cReturned);
  EnumForms(hPrinter, 1, @FormInfos, cbNeeded, cbNeeded, cReturned );
  j := 0;
  for i:= 1 to cReturned  do 通過輪尋找到300k的紙張的紙張類型排序號
    if FormInfos[i].pName = '300k' then j:=i;
  if j=0 then 
  begin
    addpage();
    j := cReturned + 1;
  end; //如無300k紙張則添加
  GetPrinter(hPrinter,2,Nil, 0, @NeededSize);
  GetPrinter(hPrinter, 2, @ppo, NeededSize, @NeededSize);
  dev := ppo.pDevMode;
  dev.dmPaperSize := j;
  ppo.pDevMode := dev;
  SetPrinter(hPrinter,2,@ppo,0); //定義打印機列表并選擇300k紙張
  Result := True;
end;

Function MySetPrtInfo(P:Pchar;W:Integer;L:Integer):Boolean;stdcall;
 //設置打印機的紙張類型為300k，并動態修改300k的大小和邊距
var
  FormInfo: TFormInfo1;
  PaperSize: TSize;
  PaperRect: TRect;
begin
  OpenPrinter(GetDefaultPrinterName, hPrinter, nil);
  changepape(); //改變紙張類型定義
  FormInfo.Flags := FORM_USER;
  FormInfo.pName := '300K';
  PaperSize.cx := W*100;
  PaperSize.cy := L*100;
  PaperRect.Left := 0;
  PaperRect.Top := 0;
  PaperRect.Right := W*100;
  PaperRect.Bottom := L*100;
  FormInfo.Size := PaperSize;
  FormInfo.ImageableArea := PaperRect;
  SetForm(hPrinter,'300k',1,@FormInfo); //設置紙張大小
  ClosePrinter(hPrinter);
  Result := True;
end;

exports
  MySetPrtInfo;
begin
end.