R_FntStr()
 Install an external EGA or VGA font from a string
------------------------------------------------------------------------------

 Syntax
        nRetCode := R_FntStr ( cFontData [, cFontName] )

 Arguments
        cFontData       String with the font data.
                        The format is the same as from a font file.
                        The string length should be :
                        3584 bytes for EGA fonts
                        4096 bytes for VGA fonts

        cFontName       Name of the font
                        Default : 'Font loaded from string'
                        The name can be retrieved using
                        the R_FntName () function.

 Returns
        nRetCode        Return code
                        0 - FL_OKAY             No errors detected
                        1 - FL_INVALID_PARMS    Invalid parameters passed

                        N.B. the return codes are pre-defined in the header
                                file RFntLib.CH

 Description
        With the function R_FntStr () you can load and install an EXTERNAL
        font from a font file.
        The function is very usefull for building font utility programs.

        +----------------------------------------------------------------+
        |                         -+- CAUTION -+-                        |
        |                                                                |
        |     IN THE UN-REGISTERED  VERSION OF RFNTLIB THE FOLLOWING     |
        |     REGISTRATION MESSAGE WILL BE DISPLAYED AT RANDOM TIMES     |
        |     (WHILE EXECUTING THE R_FNTSTR FUNCTION) :                  |
        |                                                                |
        |     Unregistered version of RFntLib - Wait for 8 seconds.      |
        |                                                                |
        |       AFTER A 8 SECONDS DELAY THE PROGRAM WILL CONTINUE.       |
        +----------------------------------------------------------------+

 Example
        *-- Convert a VGA font file to EGA format
        *--   This is done by deleting the last two scan lines
        LOCAL   nVGAHandle := FOpen   ( 'FONT.RFV' )    && Open   VGA font
        LOCAL   nEGAHandle := FCreate ( 'FONT.RFE' )    && Create EGA font
        LOCAL   cBuffer    := Space ( 4096 )            && Buffer
        LOCAL   i

        FRead ( nVGAHandle, @cBuffer, 4096 )

        FOR i := 1 TO 256
           *-- Character loop
           FWrite ( nEGAHandle, Substr ( cBuffer, (i-1)*16 + 1, 16 ), 14 )
        NEXT

        FClose ( nVGAHandle )
        FClose ( nEGAHandle )

        *-- Install the newly created EGA font
        R_FntStr ( cBuffer, 'Converted EGA-font' )