[nvda] Re: NVDA and video hooks

I think the point here is that video hooks are a legitimate way for software to interact with one another, whereas, display chaining needs to have software sitting astride the video stream in the display driver vectors. The latter quite obviously needs to be installed , whereas merely looking at things exposed with display hooks does not. At least this is the kind of explanation I was given by Dolphin when they started to use display chaining.
The sad thing about chaining seems to be that Microsoft have never made a one size fits all driver so all the screenreader makers wrote their own using the Microsoft installation code. This at one stroke clobbers portability. 

Brian
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----- Original Message ----- From: "Chris & Doris" <chipmunks@xxxxxxx> 
To: <nvda@xxxxxxxxxxxxx>
Sent: Friday, February 20, 2009 5:29 AM
Subject: [nvda] Re: NVDA and video hooks



as far as I know, Serotek's System Access uses display hooking and
this does not require it to be run having adminstrator's  privileges
on the host computer nor does it impair its portability.

hth

Doris

At 09:44 PM 2/19/2009 -0600, you wrote:

Hello all:
I just have one quick question. When/if video hooks or intercept
drivers ever get implemented into NVDA, will this feature destroy
it's portability? The reason I ask is I often take my thumb drive on
wich I have NVDA  portable installed on  to the library, and there
computers don't have any accessibility   software installed on them,
nor do they have admin rights wich allow installation of programs.
If this does reduce there portability, then is it possible to either
be given the choice of installing them or not, or have a feature to
enable/disable them as needed. The only way I can possibly think of
to maintain NVDA's portability is to write the drivers, etc to look
for a video card, then establish an intercept, I believe this called
a display chain, but I am not a programmer. I own my own laptop,
so  installing things is no problem but I do not have such
privilages on my local library's machines.
 Thanks
Kendell Clark



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