Curious refresh rate behavior...

[Harold Hunt]

Thomas,

Well, answer me this one question:

What refresh rates does Windows 2000 allow when you set the Windows color
depth to 8 bits?

If the answer is that Windows only allows a 60 Hz refresh rate then you have
found that your driver only supports a 60 Hz refresh rate when in 8 bit
mode.  If Windows allows higher refresh rates in 8 bit mode then you have
found that DirectDraw )or the DirectDraw drivers for your video card) does
not allow a refresh rate higher than 60 Hz.  I would believe either of these
scenarios, as moving 8 bit colors to the screen requires a table lookup for
each pixel to find the associated rgb triple for that pixel.  I have no idea
how much overhead, if any, that that involves.

When you run with 'XWin -engine 1 -fullscreen -depth ?', the '-depth ?'
parameter is ignored because the GDI engine just opens a large GDI window
that covers the entire desktop.  No color depth switching takes place.  Thus
your discovery that you were actually running at 24 bits per pixel.

May I suggest that, if you can set Windows to a display depth of 8 bits with
a refresh rate of 75 Hz that you simply do this before and while running
XWin and switch back afterwards?  I really don't think there is anything
that we can do to help you other than this, as DirectDraw is simply not
allowing a 75 Hz refresh rate at 8 bits per pixel.

Hope that helps,

Harold

> -----Original Message-----
> From: cygwin-xfree-owner@cygwin.com
> [mailto:cygwin-xfree-owner@cygwin.com]On Behalf Of Thomas Chadwick
> Sent: Wednesday, April 17, 2002 2:27 PM
> To: cygwin-xfree@cygwin.com
> Subject: Re: Curious refresh rate behavior...
>
>
> >From: "Thomas Chadwick" <j_tetazoo@hotmail.com>
>
> [snip]
>
> >If I do this, I get 75Hz and 8-bit depth, but have to give up the
> >DirectDraw
> >engine:
> >
> >    XWin -engine 1 -fullscreen -depth 8
>
> I take it back.  This command-line gives me 75Hz, but not 8-bit
> depth (I get
> 24-bit).
>
>
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