Re: Jon Relay's Apple II Info Archives: Graphics Modes (repost)

[supertimer@aol.com (Supertimer)]

jonINTERNETrelayCHAT@napaVALLEYnet.CLARInet (Jon Bettencourt) wrote:

>supertimer@aol.com (Supertimer) wrote:
>
>> What about IIGS SuperHires modes?
>
>Find the info and point me to it so I can add it.

The following are IIGS Super High Resolution modes:

     The Video Graphics Chip (VGC) is a custom video chip
     that provides all of the GS' graphics modes.  All modes
     use a 12-bit palette for 4096 colors.
        --320x200 with 16 colors
        --320x200 with 256 colors: in this mode, the VGC
          is taking advantage of the fact that it has memory
          for 16 separate palettes.  Each scan line can be
          assigned any one of these 16 palettes for a total
          of 256 possible colors.  This mode requires no CPU
          assistance and is often used in games.
        --320x200 with 3200 colors: in this mode, the CPU
          is used to swap palettes into and out of video
          memory such that a separate 16 color palette can
          be used on each of the 200 scan lines for 3200
          possible colors.  This mode is often used for
          viewing graphics.
        --640x200 with 4 pure colors: this mode is bland
          and is not often used.
        --640x200 with 16 dithered colors: in this mode, the
          pixels in the graphic screen are grouped into
          even and odd columns.  The even columns can have a
          palette of 4 pure colors out of a of 4096 possible.
          The odd columns can have a second palette of 4
          pure colors.  The GS dithers the adjacent colors
          for 4x4=16 dithered colors.  This mode is widely
          used in productivity programs and also in Apple's
          Finder for the GS.
        --Fill mode: for faster rendering of graphics, the
          fill mode is a hardware mode in which an outline
          of a graphic can be drawn and the outline filled
          by a solid color without needing to draw in all the
          pixels.
        --Combinations and variations: the Apple IIGS has
          scan line interrupts.  Part of the screen can
          be in 640x200 mode and part of it can be in 320x200
          resolution.  Such split modes are sometimes used
          in paint programs, where the menu bar is in 640x200
          while the graphic is in 320x200.

>> Second Sight modes?  (should be considered otherwise you should
>> also not consider 80 columns and DHR on the IIe since the IIe also
>> required a card to get those)
>
>Same thing as the above. Find the info and I'll add it.

The Second Sight is an SVGA card with 1MB of memory
for the IIGS.  It provides PC type SVGA modes.  This
means 640x480 at 24-bit color up to 1024x768 at 256
colors.  800x600 at intermediate color depth is also
possible.  Basically the same modes as a PC SVGA
card with 1MB of video memory.  The Second Sight was
one of the last major peripherals I got for my IIGS and
as you can imagine, viewing JPEG, PICT, and GIF pics
that originated on the PC is a snap with the card.  You
can actually plug in an SVGA monitor and use it for
best results or it works on the standard Apple IIGS
monitor but limited to 640x400.  It can also use Mac
monitors with an adapter.