Re: using XDPS backend to display NextOpenStep apps remotely

[Ondrej Florian]

I managed to find out what an app is actually sending out to the display server.
There is NXShowPS argument you can pass to any application which will print out 
any data coming back and forth. 
It is basically streaming postscript (as expected ;-). ...very cool to see in 
real-time.
The problem is that it includes a lot of extensions like "set active window" or 
"change window status" which is not part of "standard" DPS. All of that would 
all have to be reverse engineered and Incorporated into DPS server  + 
windowmanager.
...a lot of work and non of it is documented...

What I am thinking about doing is capturing actual bitmap of a window.
Kind of like VNC would do but capture it per window instead of entire screen.

I know it can be done. Grab.app does capture window even if it covered by other 
window, but I didn't find the right API yet ;-)

On 2024-04-29 00:37:34 +0200 Gregory Casamento <greg.casamento@gmail.com> wrote:

> Sweet!!!   Please share your progress.  I would love to learn more.
> 
> Gregory Casamento
> GNUstep Lead Developer / Black Lotus, Principal Consultant
> http://www.gnustep.org - http://heronsperch.blogspot.com
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> https://www.openhub.net/languages/objective_c
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> 
> 
> On Sun, Apr 28, 2024 at 17:27 Ondrej Florian <onflapp@yahoo.com> wrote:
> 
>> Thanks Gregory.
> 
>> Communicating between GNUstep and Next is actually not that bad.
>> I managed to sync pasteboard by using simple TCP client/server and
>> transferring strings, RTF or TIFF data as appropriate.
> 
>> The Previous has NFS server built-in, so working with files is just matter
>> of transforming local paths to network paths and then executing appropriate
>> app (using the simple TCP client/server) in Next.
> 
>> I mapped Previous into its own windowmaker workspace.
>> That works reasonably well but it is somewhat limiting for day to day
>> usage.
> 
>> I'll take a look at DSP server as you've suggested and see where it leads
>> me ;-).
> 
>> On 2024-04-28 22:41:53 +0200 Gregory Casamento <greg.casamento@gmail.com>
>> wrote:
> 
>>> Hey,
>>> 
>>> I had given this some thought some years ago.   Let's go over what you
>> said
>>> you need...
>>> 
>>> 1) running the next emulator headless...
>>> 
>>> I think this could be accomplished, no problem.   You could either use
>>> Previous or qemu (running the intel version of OPENSTEP).
>>> 
>>> 2) Communication via DPS...
>>> 
>>> You don't need XDPS for this.  The XDPS backend for GNUstep was an
>> attempt
>>> to use the Display Postscript that was going to be integrated into X11,
>> but
>>> this never happened because the people on the project determined that
>>> postscript was better done as a client/app side thing rather than in the
>> X
>>> server itself.   Here is the discussion...
>>> 
>>> 
>> https://www.x.org/releases/X11R7.5/doc/graphics/dps.html#:~:text=Display%20Postscript%20
>>> (or%20DPS%20for,code%20from%20client%20to%20server.
>>> 
>>> One place you can get information is from the following website, he has
>>> done a fair bit of hacking on PS and DPS...
>>> 
>>> https://www.wizards.de/~frank/franksprojects.html
>>> 
>>> Of particular interest is project Akira.   It may be possible to connect
>> to
>>> the DPS server over a port and communicate with it, but no one has done
>>> that and I am not sure the remote capability is present either in the
>>> DGS/DPS backend that X was planning.
>>> 
>>> 3) Pasteboard bridging...
>>> 
>>> The pasteboard on the NeXT likely uses the typedstream style of encoding
>>> that was common on the NeXT machine.   This encoding has never been
>> reverse
>>> engineered... one possible resource for this is a python program I found
>>> recently that discovers, in part, the structure of typedstream
>> archives...
>>> 
>>> https://github.com/dgelessus/python-typedstream.git
>>> 
>>> The tool doesn't get the data it just breaks down what data is there
>> which
>>> could be instrumental in reverse engineering it.
>>> 
>>> CONCLUSION...
>>> 
>>> As you can see there is a fair amount of work here.   This is all of the
>>> information I have discovered over the years on this.  If I find anything
>>> else or dig up any other information that might be useful I will let you
>>> know.
>>> 
>>> Yours, GC
>>> 
>>> 
>>> 
>>> 
>>> On Sun, Apr 28, 2024 at 2:32 PM Ondrej Florian <onflapp@yahoo.com>
>> wrote:
>>> 
>>>> Hi everyone,
>>> 
>>>> I am working on integrating the Next emulator
>>>> (http://previous.alternative-system.com/)
>>>> into the GSDE  (https://github.com/onflapp/gs-desktop).
>>> 
>>>> I understand the original Next/OpenStep could display apps remotely (I
>>>> guess that's where NXHost arg comes from).
>>>> Does anyone know how this actually worked?
>>>> Could it be possible to use XDPS backed for for that?
>>> 
>>>> My hope is that I could run the Next emulator "headless" and display
>>>> the original apps along side GNUstep apps in the same desktop (plus
>>>> bridging pasteboard etc. ;-).
>>>> Kind of like how the classic mode worked on OS X.
>>> 
>>>> Any ideas?
>>> 
>>>> Many thanks,
>>>> Ondrej
>>> 
>>> 
>>> 
>>> 
>>> 
> 
> 
>