NAME

       vga_getmodeinfo - returns pointer to mode information structure for a mode

SYNOPSIS

       #include <vga.h>

       vga_modeinfo *vga_getmodeinfo(int mode );

DESCRIPTION

       The  function  returns  a  pointer to a statical allocated mode information structure which is filled out
       with details for a video mode mode.

       #include <vga.h> defines vga_modeinfo as

       typedef struct {
            int width;
            int height;
            int bytesperpixel;
            int colors;
            int linewidth;
            int maxlogicalwidth;
            int startaddressrange;
            int maxpixels;
            int haveblit;
            int flags;
       /* Extended fields, not always available: */
            int chiptype;
            int memory;
            int linewidth_unit;
            char *linear_aperture;
            int aperture_size;
            void (*set_aperture_page) (int page);
            void *extensions;
       } vga_modeinfo;

       If the given mode is out of range, NULL is returned.  Beware, even when vga_getmodeinfo() returns details
       about a certain mode, you must check if it is currently available (may depend on memory  size  and  other
       details) with vga_hasmode (3).

       The fields meaning in detail:

   Basic mode details
       width  Width of mode in pixels.

       height Height of mode in pixel lines.

       bytesperpixel
              Bytes  per pixel. This is 1, 2, 3, or 4 (for 256, 32K & 64K, 16M, 16M$ modes) and 0 for planar VGA
              modes.

       linewidth
              Logical scanline width in bytes. This is the memory offset between two pixels above each other  in
              two  adjacent  screen  lines. It is not valid to assume that linewidth == width * bytesperpixel in
              general!

       colors The number of colors which you can display simultaneously 2, 16, 256, 32768, 65536,  or  16777216.
              Generally 16 and 256 mean that a color lookup table is used. 2 means that only black/white is used
              and the others use some high/true color mode.

   Possible modifications of the memory layout
       maxlogicalwidth
              The   maximum   logical  scanline  width  (in  bytes)  which  you  can  set  for  this  mode  with
              vga_setlogicalwidth(3) while still expecting a perfect screen image.

       startaddressrange
              Mask of changeable bits of start address (in pixels). All bits zero in startaddressrange must also
              be zero in a call to vga_setdisplaystart(3) when you want to avoid noisy video signals.

   Memory size
       maxpixels
              Maximum number of pixels that will fit in a logical screen (depends on video memory).

   Further, advanced capabilities
       haveblit
              Indicates whether the following bitblit functions are  available.  It  is  a  logical  or  of  the
              following predefined values (which each have only one bit set).

              HAVE_BITBLIT
                     has vga_bitblt(3) old style accelerator function.

              HAVE_FILLBLIT
                     has vga_fillblt(3) old style accelerator function.

              HAVE_IMAGEBLIT
                     has vga_imageblt(3) old style accelerator function.

              HAVE_HLINELISTBLIT
                     has vga_hlinelistblt(3) old style accelerator function.

              HAVE_BLITWAIT
                     has vga_blitwait(3) old style accelerator function.

       flags  Miscellaneous  flags.  It is a logical or of the following predefined values (which each have only
              one bit set).

              HAVE_RWPAGE
                     vga_setreadpage(3) and vga_setwritepage(3) are available in this mode.

              IS_INTERLACED
                     Mode is interlaced, which means it will tend to flicker and the user might  be  happier  if
                     the application chooses another mode.

              IS_MODEX
                     Mode  user  mode X like memory layout (planar 256 colors VGA mode). See vga_setmodeX(3) for
                     some explanations.

              IS_DYNAMICMODE
                     Dynamically loaded mode. This mode was defined in /etc/vga/libvga.conf by the user. He will
                     probably prefer its usage. However, usually this should be of no interest to the user.

              CAPABLE_LINEAR
                     Mode can be set to linear addressing with vga_setlinearaddressing(3).

              IS_LINEAR
                     Linear addressing is already enabled for this mode.

              EXT_INFO_AVAILABLE
                     The extended fields in this information structure  are  set  to  sensible  information.  If
                     EXT_INFO_AVAILABLE  is  not  set  you should even not access these fields as you might have
                     encountered an old version of svgalib and the fields migth actually not have been allocated
                     at all.

              RGB_MISORDERED
                     For 16M4 modes it means that the 4 bytes per pixel actually mean 0BGR rather than  BGR0  as
                     per default. For 16M mode it means that the 3 bytes actually mean RGB instead of BGR.

                     The first is a general limitation of Mach32, the latter one of Mach32 with a ramdac of type
                     4. The vga_ drawing functions takes this into account.

              HAVE_EXT_SET
                     A vga_ext_set(3) is available and can be called.

   Extended mode information
       You must check for EXT_INFO_AVAILABLE in flags before trying to access these values.

       chiptype
              the  chiptype  that  was  detected/set.  This specifies a subtype of the current vga_getchipset(3)
              setting whose value depends on the chipset. It should be only used for debugging or internally.

       memory memory available on the SVGA card in KB.

       linewidth_unit
              use only a multiple of  this  value  for  set_logicalwidth(3)  or  set_displaystart(3)  to  ensure
              graceful alignment of lines onto the vga memory in this mode and for noiseless video signals.

       linear_aperture
              ptr    to    a    mmaped   secondary   linear   framebuffer   (not   related   to   the   use   of
              vga_setlinearaddressing(3)) (NULL if unavailable)

       aperture_size
              size of the secondary framebuffer in KB. 0 if unavailable.

       set_aperture_page
              a function taking an int as parameter to select a page in the framebuffer addressed by read/writes
              to this memory arey (if aperture_size < memory.

       extensions
              pointer to additional, internal, chipset specific info (contents of the EEPROM for Mach32 driver.)

       The vgatest(6) demo displays most of this info for all supported modes.

SEE ALSO

       svgalib(7),  vgagl(7),  libvga.config(5),  vgatest(6),   vga_hasmode(3),   vga_init(3),   vga_setmode(3),
       vga_getcurrentmode(3),       vga_getdefaultmode(3),       vga_lastmodenumber(3),      vga_getmodename(3),
       vga_getmodenumber(3),    vga_setlogicalwidth(3),    vga_bitblt(3),    vga_fillblt(3),    vga_imageblt(3),
       vga_hlinelistblt(3),     vga_blitwait(3),     vga_setmodeX(3),     vga_getchipset(3),     vga_ext_set(3),
       vga_setlinearaddressing(3)

AUTHOR

       This manual page was edited by Michael Weller <eowmob@exp-math.uni-essen.de>. The  exact  source  of  the
       referenced function as well as of the original documentation is unknown.

       It   is   very   likely   that   both   are   at  least  to  some  extent  are  due  to  Harm  Hanemaayer
       <H.Hanemaayer@inter.nl.net>.

       Occasionally this might be wrong. I hereby asked to be excused by the original author  and  will  happily
       accept any additions or corrections to this first version of the svgalib manual.

Svgalib (>= 1.2.11)                               27 July 1997                                vga_getmodeinfo(3)