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       ggiCheckMode, ggiCheckTextMode, ggiCheckGraphMode, ggiCheckSimpleMode -
       Check or negotiate a text/graphics mode on a visual


       int ggiCheckMode(ggi_visual_t visual, ggi_mode *tm);

       int ggiCheckTextMode(ggi_visual_t visual, int cols, int rows,
                            int vcols, int vrows, int fontx, int fonty,
                            ggi_graphtype type, ggi_mode *suggested_mode);

       int ggiCheckGraphMode(ggi_visual_t visual, int x, int y,
                             int xv, int yv, ggi_graphtype type,
                             ggi_mode *suggested_mode);

       int ggiCheckSimpleMode(ggi_visual_t visual, int xsize, int ysize,
                              int frames, ggi_graphtype type, ggi_mode *md);


       ggiCheckMode checks whether or not the given  mode  will  work  on  the
       visual.   If  it  does  not  work,  it will modify the values of passed
       ggi_mode(3) structure so that the mode works.   This  mode  negotiation
       allows the application to discover modes that are both supported by the
       visual and suitable to the application.

       ggiCheckTextMode checks whether the text mode with  the  given  visible
       and virtual dimensions and the font size is supported.

       ggiCheckGraphMode  checks  whether  the  graphics  mode  with the given
       visible and virtual dimensions and type is supported.

       ggiCheckSimpleMode checks whether the  graphics  mode  with  the  given
       visible  dimensions, type, and number of buffers is supported.  This is
       used in lieu of ggiCheckGraphMode if multiple buffering is desired.

       For   ggiCheckTextMode,   ggiCheckGraphMode   and   ggiCheckSimpleMode,
       suggested_mode  is either NULL or a pointer to a ggi_mode(3) which will
       be filled in with the negotiated mode parameters.


       For ggiCheckTextMode and ggiCheckGraphMode, a return of  0  means  that
       the corresponding set mode call for this mode would succeed. Otherwise,
       the mode given cannot be set. In this case, suggested_mode  is  changed
       to the suggested mode.

       If  the  only modifications made to the structure is replacing GGI_AUTO
       or GT_AUTO value, the functions return success.


       First, if GGI_AUTO (or GT_AUTO for the graphtype) is specified for  any
       of  the members of tm, these are filled in with the recommended values.
       The values could be to a maximum, preferred, or GGI_DEFMODE resolution,
       and will be compatible with any other constraints.

       An  application  that  does  not care about a specific parameter should
       always specify GGI_AUTO or GT_AUTO for it.

       The resulting mode is guaranteed to be valid; if not,  the  application
       can assume that it cannot set any mode on the given visual and give up.

       The suggested mode is derived as follows:

       1   Resolutions are always adjusted up. If you  want  the  next  lower,
           start  out  at  1x1  (or somewhere else reasonable) and jump up the

           Only if the maximum resolution would be exceeded,  resolutions  are
           adjusted down to the maximum.

           The  above  applies  to  visible  and  virtual  size.  If  there is
           interference between them, the visible size is satisfied  first  if
           possible, then the virtual size.

           The  adjustment  of  one value do not normally affect other values.
           For example, if (visible) 320x100 (virtual 320x200)  is  requested,
           the  visible size may be adjusted to 320x200, but virtual size will
           be left alone. Of course, if the virtual  size  becomes  less  than
           visible size, then it will be adjusted as well.

       2   Font  sizes are handled the other way round: they are adjusted down
           except when there is nothing below.

       3   A specific graphtype is changed only if the card does  not  support
           it  at  all.   If  the maximum resolution is exceeded, then that is
           adjusted down and not the graphtype.  This  assumes,  that  if  you
           request  true-color,  you  really  want  that  and not so badly the
           resolution you requested. If this is not the case,  you  can  still
           retry with another graphtype or GT_AUTO.

           If  graphtype  is  changed,  it  is  adjusted in ascending order if
           possible: e.g. 1->4->8->15->16->24/32 bit. So you always get a mode
           which can do more than you requested. Only when no better modes are
           available, the type is adjusted down.


       Try a 320x200x8 mode:

       ggi_mode sug_mode;
       err = ggiCheckGraphMode(vis, 320, 200, GGI_AUTO, GGI_AUTO, GT_8BIT,
       if(err) {
             /* Check if returned mode is ok... */
       else {
             ggiSetMode(vis, &sug_mode);


       ggiOpen(3), ggiSetMode(3), ggi_mode(3)