How to Print a Single Line Without Formfeed

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows version 3.10

SUMMARY

This article shows by example how to have an application print one line at a time without a formfeed. Windows does not inherently provide this ability because it is in direct conflict with the design philosophy of a multitasking operating system.

One method of single-line printing, including sample code, is provided here. This method uses the combination of the RAW.DRV sample printer driver and the PASSTHROUGH escape, and supports printing over a network. It has the following limitations:

• This method is not conducive to shared printing. If another application prints, it will assume that the printer is currently at the top of a page, which may not be the case if this code is being used.
• This method is only compatible with dot matrix, daisywheel, or other printers capable of printing a single line or single line feed. It will not work with LaserJet printers that must print a page at a time.

MORE INFORMATION

If you are sure no other application will use the same printer, you can have your application print one line at a time to a dot matrix printer without issuing a formfeed. Use the RAW.DRV sample printer driver and the PASSTHROUGH escape to accomplish this. Follow these steps:

1. Download RAW.DRV and place it in the \WINDOWS directory. For more information about RAW.DRV, including instructions for download, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q35708

      TITLE     : SAMPLE: Using a Device Driver to Send Binary Data to Printer
   
      Do not install this driver as the default printer driver. It is a sample
      driver and is not intended to be used for commercial applications.
   
   

2. Call the PrintLineNow function by using the following code fragment:

   // The Abort Procedure for printing (a generic AbortProc)
   // This procedure needs to listed be in the Exports section
   //    of the .DEF file
   

  MSG msg;

  while(PeekMessage(&msg, NULL, 0, 0, TRUE))
  {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  return TRUE;

// The function that prints one line without formfeed

  #define   LINEBUFFER_LENGTH 80 //or dynamically alloc enough space
  HDC       hDC;
  char      pOutput[LINEBUFFER_LENGTH+sizeof(WORD)];
  DOCINFO   di;
  ABORTPROC lpfnAbortProc;

  // Buffer size is LINEBUFFER_LENGTH bytes
  if( cbBytes > LINEBUFFER_LENGTH )
     return FALSE;

  // Get the DC using the RAW.DRV driver
  if( (hDC = CreateDC( "RAW", NULL, "LPT1", NULL ) ) == NULL )
    return FALSE;

  // Set up an Abort Procedure
  if((lpfnAbortProc = MakeProcInstance(AbortProc, hInst)) == NULL)
    {
      DeleteDC( hDC );
      return FALSE;
    }
  if( SetAbortProc( hDC, lpfnAbortProc ) <= 0 )
    {
      DeleteDC( hDC );
      FreeProcInstance( lpfnAbortProc );
      return FALSE;
    }

  // Start a Document
  di.cbSize = sizeof( DOCINFO );
  di.lpszDocName = "MyDoc";
  di.lpszOutput = NULL;
  if( StartDoc( hDC, &di ) <= 0 )
    {
      DeleteDC( hDC );
      FreeProcInstance( lpfnAbortProc );
      return FALSE;
    }

  // The start of a page
  if( StartPage( hDC ) <= 0 )
    {
      DeleteDC( hDC );
      FreeProcInstance( lpfnAbortProc );
      return FALSE;
    }

  // Put data in the buffer and send to the printer
  *(WORD *)pOutput = cbBytes;
  memcpy( &(pOutput[sizeof(WORD)]), pData, cbBytes );
  if( Escape( hDC, PASSTHROUGH, 0, pOutput, NULL ) <= 0 )
    {
      DeleteDC( hDC );
      FreeProcInstance( lpfnAbortProc );
      return FALSE;
    }

  // The end of the page
  if( EndPage( hDC ) < 0 )
    {
      DeleteDC( hDC );
      FreeProcInstance( lpfnAbortProc );
      return FALSE;
    }

  // End the Document
  if( EndDoc( hDC ) < 0 )
    {
      DeleteDC( hDC );
      FreeProcInstance( lpfnAbortProc );
      return FALSE;
    }

  // Clean up
  DeleteDC( hDC );
  FreeProcInstance( lpfnAbortProc );
  return TRUE;   // Success
}