HOWTO: How to Print a Single Line Without Formfeed (124649)

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:

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:
35708 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.

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(&amp;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
   }