急问：如何动态改变打印机纸张类型

Question

比如打印机现在的预设纸张是A4，现有一程序需要一个用户自定义类型如A2A，那么如何在程序中把打印机预设的A4改成A2A，请大家帮忙，谢谢．

Answer 1

uses
  Windows,
  WinSpool,  //一定要 uses 这玩意
  SysUtils,
  Registry,
  Classes;
//=================================
function TForm1.GetDeviceName():String;
var MyReg: TRegistry;
    szDeviceName: String;
begin
  MyReg := TRegistry.Create;
  try
    MyReg.RootKey := HKEY_CURRENT_CONFIG;
    if MyReg.OpenKey('\System\CurrentControlSet\Control\Print\Printers',False) then
      szDeviceName:=MyReg.ReadString('Default')
    else
      szDeviceName:='';
  except
    MyReg.Free;
  end;
  result:=szDeviceName;
end;//===================================
function TForm1.GetPortName(): String;
var MyReg: TRegistry;
    szPortName: String;
begin
  MyReg := TRegistry.Create;
  try
    MyReg.RootKey := HKEY_LOCAL_MACHINE;
    if MyReg.OpenKey('\System\CurrentControlSet\Control\Print\Printers\'+GetDeviceName(),False) then
      szPortName:=MyReg.ReadString('Port')
    else
      szPortName:='';
  Except
    MyReg.Free;
  end;
  result:=szPortName;
end;
//================================
//nOrient  打印方向
//nHandle  打印机的Handle
// 调用 SetPaperSize（2000，3000，1，printer.handle）;
// 调用后，修改系统的打印机的纸张大小的设置。 
function TForm1.SetPaperSize(var nWidth,nHeight,nOrient:Word;var nHandle: THandle):integer; 
var
//  szPrinterKey: array[0..99] of Char;
  szDeviceName: String;
  szPort: String;
//  cbBuffer: DWORD;
//  dwRV: DWORD;
  dwPapers: DWord;
  lpwPapers: array[0..255] of Word;
  fSupportUserDefind: Boolean;
  fSupportA3: Boolean;
  fSupportA4: Boolean;
  fSupportB5: Boolean;
  hDriver: THandle;
  hMem: HGLOBAL;
  lpDevMode: Pdevicemode;
  a1: Pdevicemode;
  i: integer;
begin
  fSupportUserDefind:=FALSE;
  fSupportA3:=FALSE;
  fSupportA4:=FALSE;
  fSupportB5:=FALSE;  //取当前默认打印机设备名
  szDeviceName:=GetDeviceName();
  if szDeviceName='' then
    result:=-1;  //取打印机端口
  szPort:=GetPortName();
  if szPort='' then
    result:=-2;  //取打印机支持的全部纸型
  dwPapers:=DeviceCapabilities(PChar(szDeviceName),PChar(szPort),DC_PAPERS,@lpwPapers,nil);
  if (dwPapers<1)or(dwPapers>256) then
      result:=-3;  //判断打印机是否支持自定义、A3、A4、B5纸型
  while (dwPapers > 0) do
  begin
    case DWORD(lpwPapers[dwPapers]) of
      DMPAPER_USER: fSupportUserDefind:=TRUE;
      DMPAPER_A3: fSupportA3:=TRUE;
      DMPAPER_A4: fSupportA4:=TRUE;
      DMPAPER_B5: fSupportB5:=TRUE;
    end;
    dwPapers:=dwPapers-1;
  end;  //取打印机的DeviceMode
  a1:=nil;
  if not(OpenPrinter(PChar(szDeviceName),hDriver,nil)) then result:=-4;
  hMem:=GlobalAlloc(GPTR,DocumentPropertiesA(nHandle,hDriver,PChar(szDeviceName),a1^,a1^,0));
  lpDevMode:=GlobalLock(hMem);
  a1:=nil;
  DocumentProperties(nHandle,hDriver,PChar(szDeviceName),lpDevMode^,a1^,DM_OUT_BUFFER);  //设置纸型或大小
  i:=0;
  if ((nWidth=2970)and(nHeight=4200))and(fSupportA3) then i:=1;
  if ((nWidth=2100)and(nHeight=2970))and(fSupportA4) then i:=i+2;
  if ((nWidth=1820)and(nHeight=2570))and(fSupportB5) then i:=i+3;  case i of
    1: begin    //A3
         lpDevMode.dmFields:=DM_PAPERSIZE;
         lpDevMode.dmPaperSize:=DMPAPER_A3;
       end;
    2: begin   //A4
         lpDevMode.dmFields:=DM_PAPERSIZE;
         lpDevMode.dmPaperSize:=DMPAPER_A4;
       end;
    3: begin   //B5
         lpDevMode.dmFields:=DM_PAPERSIZE;
         lpDevMode.dmPaperSize:=DMPAPER_B5;
       end;
    else
       if fSupportUserDefind then
       begin
         lpDevMode.dmFields:=DM_PAPERSIZE or DM_PAPERWIDTH or DM_PAPERLENGTH;
lpDevMode.dmPaperSize:=DMPAPER_USER;
lpDevMode.dmPaperWidth:=nWidth;
lpDevMode.dmPaperLength:=nHeight;
       end
       else
         lpDevMode.dmFields:=0;
  end;  //设置方向
  case nOrient of
    0: begin
         lpDevMode.dmFields:=lpDevMode.dmFields or DM_ORIENTATION;
lpDevMode.dmOrientation:=DMORIENT_PORTRAIT;
       end;
    1: begin
         lpDevMode.dmFields:=lpDevMode.dmFields or DM_ORIENTATION;
  lpDevMode.dmOrientation:=DMORIENT_LANDSCAPE;
       end;
  end;  a1:=nil;
  DocumentProperties(nHandle,hDriver,PChar(szDeviceName),a1^,lpDevMode^,DM_IN_BUFFER or DM_UPDATE);
  GlobalUnlock(hMem);
  GlobalFree(hMem);
  ClosePrinter(hDriver);  result:=1;
end;