OPENMASK( nTop, nLeft, nBot, nRight, cText,;
                  nType, nColor1, nColor2)-> cScreen 

   Draws MS-WINDOWS-like Windows, type nType on position nTop, nLeft,
   nBottom, nRight with the title cText.
   OpenMask ist the heart of the screen-functions, you can create
   small PopUp-Windows as well as the main screen of Demo.prg with it.

   OpenMask recognizes if you loaded a different Font, only if this is
   the case, Icons, Frames and such like in MS-WINDOWS will be shown.
   Without loading SoundVis.016 you'll get a your usual borders you were
   working with before you came across this Library <g>.

   The mouse will recognize all 'points of interest' of the last
   opened Window; CloseIcon, MoveIcon etc. will return a special
   code (defined in SoundVis.ch)

   These 'points of interest' are only available for the current
   Window, if you open another one later, make sure to save the
   MousePositions with Save_Mse(); Rest_Mse() will restore
   them, when you return to that previous Window.



   PARAMETERS:  nTop     Top Row       0-25,
                nLeft    Left Column   0-80,
                nBot     Bottom Row    0-25,
                nRight   Right Column  0-80,

               cText    title, will be centered
               nTyp     TypesOfWindows: a bitcoded number
                        bit 0 = CloseButton    yes/no
                        bit 1 = MoveButton     yes/no
                        bit 2 = BarMenu        yes/no
                        bit 3 = Scrollbar      yes/no
                        bit 4/5 Frame
                            0 = single frame (without SoundVis.016)
                            1 = double frame (only! without SoundVis.016)
                            2 = Graficframe  (only with SoundVis.016)
                            3 = Top is empty (Header)

               nFarbe1  Clipper-Colorcode of the TopRow
               nFarbe2  Window/FrameColor
                        These two Parameters are optional, if you
                        don't pass them, SetPref ( C_MASKWIN / C_MASKHEAD )
                        settings and Colors will be taken.


   EXAMPLE:

   LOCAL cPoints := Save_MSE()
   LOCAL cScreen := OpenMask ( 6, 22, 21, 65, 'System-Info', 51, 112, 144)

          A Window is opened at 6,22 to 21,65 title is 'System-Info'
          The WindowType is:

                    Dec.51 = Binary 00110011
                                    +|||||+ with CloseButton
                                     +|||+ with MoveButton
                                      ||+ without MenuRow
                                      |+ without ScrollBar
                                      + 3, means GraficFrame

          The background is being packed and written to cScreen

   RETURN VALUES:

      cVariable with the overwritten (packed) background screen