Help: how to disable the screen capture on OS X ??

[Patrick Stadelmann]

In article <c8cda9c0.0308120141.6e500fa2@posting.google.com >,
[email]xxiankuan@yahoo.com[/email] (Xiao Xiankuan) wrote:

> I want to disable screen capture on Mac X. I mean how to disable the
> Cmd-shift-3 shortcut, Cmd-Shift-Ctrl-3, Cmd-Shift-4, Cmd-Shift-Ctrl-4
> etc..

There's no documented way for doing this. See question #18 :
[url]http://developer.apple.com/technotes/tn2002/tn2062.html[/url]

> AND the use of Grab to take a picture of the screen.

Even if you could, what about the third-party utilities ?

Patrick
--
Patrick Stadelmann <Patrick.Stadelmann@unine.ch>

[Frederick Cheung]

On Tue, 12 Aug 2003, Patrick Stadelmann wrote:

> In article <c8cda9c0.0308120141.6e500fa2@posting.google.com >,
> [email]xxiankuan@yahoo.com[/email] (Xiao Xiankuan) wrote:
>

> > I want to disable screen capture on Mac X. I mean how to disable the
> > Cmd-shift-3 shortcut, Cmd-Shift-Ctrl-3, Cmd-Shift-4, Cmd-Shift-Ctrl-4
> > etc..

>
> There's no documented way for doing this. See question #18 :
> [url]http://developer.apple.com/technotes/tn2002/tn2062.html[/url]
>

> > AND the use of Grab to take a picture of the screen.

>
> Even if you could, what about the third-party utilities ?

not to mention /usr/sbin/screencapture (which is what gets called when you
use the various shortcuts). Suppressing the shortcuts wouldn't prevent the
user from running the program manually.

Fred

[Patrick]

Frederick Cheung wrote:

> On Tue, 12 Aug 2003, Patrick Stadelmann wrote:
>
>

>>In article <c8cda9c0.0308120141.6e500fa2@posting.google.com >,
>> [email]xxiankuan@yahoo.com[/email] (Xiao Xiankuan) wrote:
>>
>>

>>>I want to disable screen capture on Mac X. I mean how to disable the
>>>Cmd-shift-3 shortcut, Cmd-Shift-Ctrl-3, Cmd-Shift-4, Cmd-Shift-Ctrl-4
>>>etc..

>>
>>There's no documented way for doing this. See question #18 :
>>[url]http://developer.apple.com/technotes/tn2002/tn2062.html[/url]
>>
>>

>>>AND the use of Grab to take a picture of the screen.

>>
>>Even if you could, what about the third-party utilities ?

>
>
> not to mention /usr/sbin/screencapture (which is what gets called when you
> use the various shortcuts). Suppressing the shortcuts wouldn't prevent the
> user from running the program manually.

Deleting it or remaining it would though! Replace it with a simple
splash screen which says something like "Screen Capture has been
disabled on this machine".


--

Patrick

----------------------------------------------------------------------

[Tom Harrington]

In article <3F3931C8.9010003@netscape.net>,
Patrick <pat102345@netscape.net> wrote:

> Frederick Cheung wrote:

> > not to mention /usr/sbin/screencapture (which is what gets called when you
> > use the various shortcuts). Suppressing the shortcuts wouldn't prevent the
> > user from running the program manually.

>
> Deleting it or remaining it would though! Replace it with a simple
> splash screen which says something like "Screen Capture has been
> disabled on this machine".

That sounds like a good, quick way of getting seriously pissed off
users. There may be cases where it's worth shutting off screen capture
of the application (e.g. Apple's DVD player app). But shutting it off
for the entire system, at all times? That's an incredibly bad idea.

--
Tom "Tom" Harrington
Macaroni, Automated System Maintenance for Mac OS X.
Version 1.4: Best cleanup yet, gets files other tools miss.
See [url]http://www.atomicbird.com/[/url]

[Patrick]

Tom Harrington wrote:

> In article <3F3931C8.9010003@netscape.net>,
> Patrick <pat102345@netscape.net> wrote:
>
>

>>Frederick Cheung wrote:
>>

>>>not to mention /usr/sbin/screencapture (which is what gets called when you
>>>use the various shortcuts). Suppressing the shortcuts wouldn't prevent the
>>>user from running the program manually.

>>
>>Deleting it or remaining it would though! Replace it with a simple
>>splash screen which says something like "Screen Capture has been
>>disabled on this machine".

>
>
> That sounds like a good, quick way of getting seriously pissed off
> users. There may be cases where it's worth shutting off screen capture
> of the application (e.g. Apple's DVD player app). But shutting it off
> for the entire system, at all times? That's an incredibly bad idea.
>

Depends what the OP wants to shut it off for. I was assuming this was
for some sort of kiosk mode. In which case they shouldn't be running a
DVD player.

As an alternative then, use the group permissions to prevent "normal"
users or whoever from running screencapture.

--

Patrick

----------------------------------------------------------------------

[Frederick Cheung]

On Tue, 12 Aug 2003, Tom Harrington wrote:

> In article <3F3931C8.9010003@netscape.net>,
> Patrick <pat102345@netscape.net> wrote:
>

> > Frederick Cheung wrote:

> > > not to mention /usr/sbin/screencapture (which is what gets called when you
> > > use the various shortcuts). Suppressing the shortcuts wouldn't prevent the
> > > user from running the program manually.

> >
> > Deleting it or remaining it would though! Replace it with a simple
> > splash screen which says something like "Screen Capture has been
> > disabled on this machine".

>
> That sounds like a good, quick way of getting seriously pissed off
> users. There may be cases where it's worth shutting off screen capture
> of the application (e.g. Apple's DVD player app). But shutting it off
> for the entire system, at all times? That's an incredibly bad idea.
>

Although you can't use the cmd-shift- combos to take screenshots with the
dvd player (maybe the player registers a global hotkey which overrides the
default one?) screencqpture still works (OS X 10.2.6, nvidia graphics). I
seem to remember that under OS 9 they didn't need to enforce this at all
because the ATI cards used a special overlay thingy, adding in the
pictures from the dvd at a later stage. If you took a screen shot then you
just got a green (or was it brown?) rectangle.

Fred

[David Phillip Oster]

In article <c8cda9c0.0308120141.6e500fa2@posting.google.com >,
[email]xxiankuan@yahoo.com[/email] (Xiao Xiankuan) wrote:

> Can anybody help me?
> I want to disable screen capture on Mac X. I mean how to disable the
> Cmd-shift-3 shortcut, Cmd-Shift-Ctrl-3, Cmd-Shift-4, Cmd-Shift-Ctrl-4
> etc..
> AND the use of Grab to take a picture of the screen.
> It's easy (and documented) to do it on Windows but I don't know how to
> do it on OS X.

<http://groups.google.com/groups?selm=oster-0101991842530001%4010.0.2.15>

[Simon Slavin]

In article <tph-C4F496.13171812082003@localhost>,
Tom Harrington <tph@pcisys.no.spam.dammit.net> wrote:

>That sounds like a good, quick way of getting seriously pissed off
>users. There may be cases where it's worth shutting off screen capture
>of the application (e.g. Apple's DVD player app). But shutting it off
>for the entire system, at all times? That's an incredibly bad idea.

Actually, Apple's DVD app doesn't disable screen capture.
The reason you can't grab frames from DVDs using it is that
the DVD's picture information goes straight from the DVD
hardware to the screen without passing through video memory.
If you do a screen capture you'll find that the window which
shows the image contains just a dark olive colour.

[Mike Kluev]

in article BB61DAAC96683876FA@10.0.1.2, Simon Slavin at
[email]slavins@hearsay.demon.co.uk[/email]@localhost wrote on 15/08/2003 03:32:

> In article <tph-C4F496.13171812082003@localhost>,
> Tom Harrington <tph@pcisys.no.spam.dammit.net> wrote:
>

>> That sounds like a good, quick way of getting seriously pissed off
>> users. There may be cases where it's worth shutting off screen capture
>> of the application (e.g. Apple's DVD player app). But shutting it off
>> for the entire system, at all times? That's an incredibly bad idea.

>
> Actually, Apple's DVD app doesn't disable screen capture.

It does for me. When it is started cmd+sift+3 doesn't work for
me (no snapshot file created, no snapshot sound, just beep).
This happens even if I hide DVD player. Once I quit it
cmd+shift+3 starts working again.

--
Mike Kluev
PS. Remove "-DELETE-." part of my address to reply

[Mike Kluev]

In Article [email]Patrick.Stadelmann-02FEE7.13135718082003@news.fu-berlin.de[/email],
Patrick Stadelmann wrote:

> In article <BB66991E.6C84%mike@objc-source.-DELETE-.org>,
> Mike Kluev <mike@objc-source.-DELETE-.org> wrote:
>

>> in article BB61DAAC96683876FA@10.0.1.2, Simon Slavin at
>> [email]slavins@hearsay.demon.co.uk[/email]@localhost wrote on 15/08/2003 03:32:
>>

>>> Actually, Apple's DVD app doesn't disable screen capture.

>>
>> It does for me.

>
> Screen capture is indeed disabled, but not by the DVD Player.

What do you mean? If I start DVD Player screen capture is
getting disabled. If I quit it screen capture t is reenabled
again. Looks like this is DVD Player who does this.

--
Mike Kluev

PS. Remove "-DELETE-." part of my e-mail address to reply.

[Miro Jurisic]

In article <BB687AFE.1558A%mike@objc-source.-DELETE-.org>,
Mike Kluev <mike@objc-source.-DELETE-.org> wrote:

> Is it possible at all to disable "screen capture" per se?
> E.g. to prohibit reading from video RAM? Just curious.

You could remove the VRAM. That would make it hard to read it :-)

(No, I don't think so.)

meeroh

[David Phillip Oster]

In article <BB687AFE.1558A%mike@objc-source.-DELETE-.org>,
Mike Kluev <mike@objc-source.-DELETE-.org> wrote:

> In Article [email]macdev-B6B59B.02142019082003@senator-bedfellow.mit.edu[/email], Miro
> Jurisic wrote:
>

> > Screen capture is not disabled. Screen capture key combos are.

>
> Hi Miro,
>
> Is it possible at all to disable "screen capture" per se?
> E.g. to prohibit reading from video RAM? Just curious.

I can imagine replacing OS X with a custom Darwin kernel that played
with the virtual memory mapping tables on a per-process basis. Depending
on how the page tables are set up, the physical memory of the screen RAM
could be inaccessible, write-only, or generate an interrupt on each read.

Just a hand-wave. Don't ask me to write it.

[Thomas Engelmeier]

Mike Kluev <mike@objc-source.-DELETE-.org> wrote:

> Is it possible at all to disable "screen capture" per se?
> E.g. to prohibit reading from video RAM? Just curious.

AFAIK, right now readback has an performance bottleneck. Removing this
bottleneck is to be expected more or less soon.
For me, that doesn't sound like the emphasis is to remove that feature
;)

Regards,
Tom_E

[Simon Slavin]

In article <BB66991E.6C84%mike@objc-source.-DELETE-.org>,
Mike Kluev <mike@objc-source.-DELETE-.org> wrote:

>slavins@hearsay.demon.co.uk@localhost wrote on 15/08/2003 03:32:
>

>> In article <tph-C4F496.13171812082003@localhost>,
>> Tom Harrington <tph@pcisys.no.spam.dammit.net> wrote:
>>

>>> That sounds like a good, quick way of getting seriously pissed off
>>> users. There may be cases where it's worth shutting off screen capture
>>> of the application (e.g. Apple's DVD player app). But shutting it off
>>> for the entire system, at all times? That's an incredibly bad idea.

>>
>> Actually, Apple's DVD app doesn't disable screen capture.

>
>It does for me. When it is started cmd+sift+3 doesn't work for
>me (no snapshot file created, no snapshot sound, just beep).

Whoops. Sorry. You're talking about the key-combination. I
was talking about the service which it runs. Try using a
Grab application. It also occurred to me that different
versions of the OS and DVD application probably handle this
differently.