Re: NSPasteboard on X, what to do?

[Wim Oudshoorn]

You wrote:
> No. A single application could have windows displayed on multiple
> screens on
> one machine.  It could also display on another machine (though I'm not
> sure
> about using multiple displays on different machines).

Ah, I didn't know that.

> Not to me.  I see dragging and cut-and paste as inter-screen operations -
> I want them to take effect wherever the mouse pointer is.
>
> In MacOS-X (essentially OpenStep) I routinely perform a cut on one
> screen,
> move the mouse to an app on my other screen, and paste into the second
> app.
> Similarly, I drag stuff from an app on one screen to an app on the other.

Hm, I see your point, but I do not understand how dragging is supposed to work.
How do you drag from one screen to another?  (I have never
used a multi headed machine, so bear with me)

> Actually a disadvantage ... how do you drag from one screen to another?

See above.

> Most copy and paste operations are performed on a single machine ... I'd
> venture

Hm, still confused.  Suppose I log in to a server and set my Xdisplay to my
local machine.  Some other person does the same,  what do these processes in  
common??


> >
> > Grouping By Computer
> > --------------------
> >
> > * Advantages:
> > 1. Easier to implement
> > 2. Current implementation does this
> >
> > * Disadvantages
> > 1. No DnD and copy/paste between different applications
> > running on different computers but on the same screen,
> > thereby going against the X philosophy.
>
> Not sure what you mean by this ... if you are receiving a drop from
> an app on another machine, the -draggingPasteboard method provided by
> the dragging info would return a pasteboard object connected to the
> pasteboard server on which the drag originated.

This certainly can work for DnD, but what about the other pasteboards?

> I'm sure it doesn't do this at present, but that's because the appkit
> generally doesn't handle multiple screens at present.

Well, actually that is not the main problem, but see below.

> I'm pretty sure that the term 'application' is generally meant to
> describe a process which uses the AppKit.

That would be best, no problem here.

> The aspect of this I've never been so happy about is the 'all'
> What about a multi-screened, multi-keyboarded machine with more than
> one user.  Do both users share the same pasteboard server?
> I think ideally not.  Each user would get their own server (to which
> they save data)

Exactly! this is the problem.

> I completely disagree ... I hope I have shown above that the advantages
> you list for doing this do not actually exist, while the disadvantage
> you supply for grouping by computer does not exist.

Well, I still think there are quite some problems with the grouping by
Computer.

>
> We don't need any changes to support multiple screens ... where we will
> start to need to work on things is when we get multiple machines sharing
> the same screen.  When that happens we need only ensure that the
> internals
> of the DnD system supply a pasteboard to the app which is connected to
> the
> correct pasteboard server.  How we cope with a cut and paste operation
> between two apps on different machines (either on the same screen or on
> two screens of one machine) I don't know.  I think this is the tricky
> case
> but it may be rare enough to ignore.

Actually, I do not think it is rare.  Maybe the following hypothetical
situation will show some problems.  (You probably are already aware
of them)


Two servers:  A, B
Two XDisplays: S, T  (one user behind S and one user behind T)
S is running two programs P1, P2
T is runnint two programs Q1, Q2

        Server A,         Server B

 S          P1                P2
 T          Q1                Q2


Now user S, selects something for the find panel, or
for copy/past in P1.  This ends up in the pasteboard of Server A.
Now S selects application P2, and reselects the find panel, or
pastes. NOTHING happens.   (note I am not talking DnD here)

Afterwards user T opens the find panel or does a paste.
Voila, the content of what user S selected appears.

The problem is that the *all* refers, at least for me,
to all applications that I, as user, consider as the
collection of applications I am working on.

(Hm, grouping by User?)

Actually, I agree with you that copy/paste between different
screens is very nice, so we might have to implement
pasteboard by user but we have to be carefull to avoid
clashing of user names on different machines.

But I might see problems were non exist.

Wim Oudshoorn.