NAME
        InitTmpRas -- Initialize area of local memory for usage by
                        areafill, floodfill, text.

   SYNOPSIS
     InitTmpRas(tmpras, buffer, size)
                    a0       a1     d0

        void InitTmpRas( struct tmpras *, void *, ulong );

   FUNCTION
        The area of memory pointed to by buffer is set up to be used
        by rastport routines that may need to get some memory for
        intermediate operations in preparation to putting the graphics
        into the final bitmap.
        Tmpras is used to control the usage of buffer.

   INPUTS
        tmpras - pointer to a tmpras structure to be linked into
                a rastport
        buffer - pointer to a contiguous piece of chip memory.
        size - size in bytes of buffer

   RESULT
        makes buffer available for users of rastport

   BUGS
        Would be nice if RastPorts could share one tmpras.

   SEE ALSO
        areaend() flood() text() graphics/rastport.h