HOWTO: How to Print a Single Line Without Formfeed

• Microsoft Windows Software Development Kit (SDK) 3.1

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 additional information about raw.drv, including instructions for download, please see the following article(s) in the Microsoft Knowledge Base:

   Q35708 SAMPLE: Raw.exe Sends Binary Data to Printer w/Device Driver

   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
      BOOL CALLBACK AbortProc( HDC hDC, int Error )
      {
        MSG msg;
   
       while(PeekMessage(&msg, NULL, 0, 0, TRUE))
       {
          TranslateMessage(&msg);
          DispatchMessage(&msg);
        }
        return TRUE;
      }
   
      // The function that prints one line without formfeed
      BOOL PrintLineNow( char *pData, WORD cbBytes )
      {
        #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
      } 

Additional query words: NEWFRAME FF Mailing Label Form Feed GdiPrn

Keywords : kb16bitonly kbDSupport kbSDKWin16
Version : WINDOWS:3.1
Platform : WINDOWS
Issue type : kbhowto