NAME

       vga_setmode - sets a video mode

SYNOPSIS

       #include <vga.h>

       int vga_setmode(int mode);

DESCRIPTION

       vga_setmode(int  mode)  selects  the  video  mode given and clears the screen (if it was a
       graphics mode).  Basically this should be the  first  action  of  your  application  after
       calling  vga_init(3) and finding out which mode to use.  Prior to exiting your application
       should call vga_setmode(TEXT).

       vga_setmode() returns 0 on success and -1 if this mode is not available.

       From svgalib-1.4.1, if mode is -1 then vga_setmode() returns the current svgalib  version,
       in BCD format, so svgalib 1.4.1 returns 0x1410.

       mode should be one of the following, predefined values, or generally a value in range 1 <=
       mode <= vga_lastmodenumber() where  vga_modeinfo(3)  returned  details  about  this  mode.
       Instead of trying to set the mode, vga_hasmode(3) determines if the mode would actually be
       supported. It is also possible to use the  numeric  values  given  below  though  this  is
       discouraged.  They  are  commonly  used as values for the SVGALIB_DEFAULT_MODE environment
       variable to set the vga_getdefaultmode(3).

       Here are the predefined values for mode.

   Text mode
       TEXT(0) restores textmode and falls back to ordinary  text  console  handling.  All  other
       calls  switch  to  a  graphics  mode. You should set this mode prior to exiting an svgalib
       application.

   VGA compatible graphics modes
       In general, for all modes following, the first number is  the  amount  of  x  pixels,  the
       second  the  amount  of y pixels, the third the number of colors, with shortcuts 32K, 64K,
       16M, 16M4 for 32768, 65536, and 1677721. Those with 2 or more than 256  colors  use  fixed
       color mappings (either black and white or some RGB true/high color) the others make use of
       a color lookup table.

       Memory layout for the VGA modes is weird. Too weird to be  explained  here,  but  you  can
       check  the  usual  VGA literature.  vga_setmodeX(3) has a short explanation which is valid
       for all 256 color modes.

       G320x200x16(1),   G640x200x16(2),   G640x350x16(3),    G640x480x16(4),    G320x200x256(5),
       G320x240x256(6), G320x400x256(7), G360x480x256(8), and G640x480x2(9)

   Basic SVGA modes
       These use linear 256 color memory layouts similar to G320x200x256.

       G640x480x256(10), G800x600x256(11), G1024x768x256(12), and G1280x1024x256(13)

   High color SVGA modes
       These  also use linear memory layouts, but for 32K & 64K each pixel occupies two bytes and
       three for 16M. For 32K, each 16 bit word is divided into 555 bit portions  refering  to  5
       bit  red,  green,  blue part. The most significant bit is ignored by the card. For 64K the
       division is 565 allowing to specify green in a little bit more detail (Human eyes are more
       sensitive  to  green. People joke this is because our ancestors lived in trees where light
       was filtered through green leaves).

       For the 16M modes, from low to high addresses the 3 bytes are named BGR  and  specify  the
       blue, green, red parts of the pixel value.

       G320x200x32K(14),  G320x200x64K(15), G320x200x16M(16), G640x480x32K(17), G640x480x64K(18),
       G640x480x16M(19), G800x600x32K(20), G800x600x64K(21), G800x600x16M(22), G1024x768x32K(23),
       G1024x768x64K(24),    G1024x768x16M(25),   G1280x1024x32K(26),   G1280x1024x64K(27),   and
       G1280x1024x16M(28)

   High resolutions with less color numbers.
       Memory layout is probably one nibble per pixel, two pixels per byte in  a  linear  fashion
       where the most significant nibble is the left most pixel.

       G800x600x16(29), G1024x768x16(30), and G1280x1024x16(31)

   Hercules emulation mode
       Again check out the ordinary VGA literature for the memory layout.

       G720x348x2(32)

   32-bit per pixel modes
       These  are  similar  to 16M but each pixel uses four bytes. The first three are similar to
       16M but the fourth is left empty and ignored by the VGA card (you  can  store  own  status
       there).

       This  eases  pixel address calculations on the screen and drawing operations. However, 1/3
       more data has to be moved to the screen. Experiments show that usually the  higher  memory
       bandwidth used outweighs the effects of the simplified algorithms by far.

       G320x200x16M32(33),   G640x480x16M32(34),   G800x600x16M32(35),  G1024x768x16M32(36),  and
       G1280x1024x16M32(37)

   Some more resolutions
       It should by now be clear how the modes will look.

       G1152x864x16(38),      G1152x864x256(39),      G1152x864x32K(40),       G1152x864x64K(41),
       G1152x864x16M(42),     G1152x864x16M32(43),     G1600x1200x16(44),     G1600x1200x256(45),
       G1600x1200x32K(46), G1600x1200x64K(47), G1600x1200x16M(48), and G1600x1200x16M32(49)

       The vgatest(6) produces a list of supported modes for your hardware, prints some  info  on
       the modes and allows you to try each of them.

SEE ALSO

       svgalib(7),   vgagl(7),   libvga.config(5),   vgatest(6),   vga_hasmode(3),   vga_init(3),
       vga_modeinfo(3),  vga_getcurrentmode(3),   vga_getdefaultmode(3),   vga_lastmodenumber(3),
       vga_getmodename(3), vga_getmodenumber(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.