# Does anyone still use Xt for GUI development

**URL:** <https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590>\
**Category:** Development\
**Created:** [February 12, 2020, 2:10pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590 "2020-02-12T14:10:39Z")\
**Posts on this page:** 17\
**Page:** 1

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**Author:** ![ken-martin](https://discourse.vtk.org/user_avatar/discourse.vtk.org/ken-martin/32/884_2.png) [@ken-martin](https://discourse.vtk.org/u/ken-martin)\
**Post date:** [February 12, 2020, 2:10pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/1 "2020-02-12T14:10:39Z")

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There is a chunk of Xt code in VTK and I’m wondering if people still use VTK within an Xt based app. Or has everything migrated to xcb or Qt etc?

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [February 17, 2020, 10:48am UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/2 "2020-02-17T10:48:36Z")

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Open Inventor still has Xt-based API, so there might be a reason, since it represents a maintenance cost to its vendor.

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**Author:** ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Post date:** [March 16, 2020, 3:59pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/3 "2020-03-16T15:59:10Z")

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Hearing no response…now that 9.0 is branched, maybe removal for 10.0 would be something to consider?

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 16, 2020, 4:33pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/4 "2020-03-16T16:33:39Z")

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Here at work we identified a single application that uses VTK with Motif, which is based on Xt.

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**Author:** ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Post date:** [March 16, 2020, 4:51pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/5 "2020-03-16T16:51:44Z")

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Ah, sorry. I hadn’t realized Open Inventor was VTK-based.

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 19, 2020, 10:43pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/6 "2020-03-19T22:43:30Z")

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No! Where did I say that? OpenInventor is another 3D API. I cited it because they keep a Xt interface for some reason (e.g. applications that use the legacy UI).

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**Author:** ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Post date:** [March 20, 2020, 12:59pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/7 "2020-03-20T12:59:00Z")

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Oh. Why would their support of Xt affect our decision to use it? I don’t think we know of any customers using the Xt APIs through VTK (the majority probably use ParaView and therefore the Qt stuff).

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 20, 2020, 1:02pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/8 "2020-03-20T13:02:05Z")

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> [@Paulo\_Carvalho](#):
>
> Here at work we identified a single application that uses VTK with Motif, which is based on Xt.

I just cited an example.

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**Author:** ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Post date:** [March 20, 2020, 1:04pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/9 "2020-03-20T13:04:08Z")

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“that uses VTK”

So does OpenInventor use VTK or not? 😕

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 20, 2020, 1:05pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/10 "2020-03-20T13:05:06Z")

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Why are you asking that? My goodness…

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 20, 2020, 1:05pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/11 "2020-03-20T13:05:44Z")

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I think you’re trying to stir confusion.

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 20, 2020, 1:11pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/12 "2020-03-20T13:11:02Z")

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I gave you two reasons to justify Xt:

1. Another 3D API uses Xt.
2. I cited a client application using VTK with Xt.

Now you can make a better informed decision. If you decide to end Xt support, the consequences are:

1. Potential users may adopt OIV (or other 3D APIs) instead of VTK;
2. Orphaned legacy applications may demand support for old versions of VTK.

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<div class="post-metadata">

**Author:** ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Post date:** [March 20, 2020, 1:31pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/13 "2020-03-20T13:31:16Z")

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Here’s what I was reading in this thread:

- Anyone using VTK+Xt?
- OpenInventor uses Xt (no indication of relation to VTK)
- I suggest removing it
- You reply that you identified an application
- I assume that it is the OpenInventor you mentioned earlier and reply to that effect

Basically, I was assuming OpenInventor _was_ your application because of the way your “we identified a single application” and my reading that your tone seemed indicate that you had already mentioned it before.

> [@Paulo\_Carvalho](#):
>
> Another 3D API uses Xt.

I don’t think we’d make a decision based on such things. If others still supported, e.g., SGI, I think we’d still drop it (if it was a decision to make today).

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<div class="post-metadata">

**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 20, 2020, 1:49pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/14 "2020-03-20T13:49:55Z")

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> [@ben.boeckel](#):
>
> I was assuming OpenInventor _was_ your application

Oh… I thought OIV was fairly known int the 3D developer community. Sorry about that.

> I don’t think we’d make a decision based on such things.

So, what’s the point of starting a discussion? Simply take it off and be done with it.

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<div class="post-metadata">

**Author:** ![ken-martin](https://discourse.vtk.org/user_avatar/discourse.vtk.org/ken-martin/32/884_2.png) [@ken-martin](https://discourse.vtk.org/u/ken-martin)\
**Post date:** [March 20, 2020, 2:03pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/15 "2020-03-20T14:03:18Z")

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I appreciate the feedback as it helped me gauge the risks of removing Xt.

I have removed the dependence on Xt from the XRenderWindowInteractor. The class now only relies on Xlib. It made the support for Vulkan a bit easier to implement and cleaner. I’m not sure if that will even be a problem for Xt based apps. They may have to change how they parent a vtk window or add a bit of glue code themselves to do it like the old Xt based interactor style did. It might be a really simple change or nothing at all. But it is out there now. If it turns out to be a big issue we can always bring back the old XRenderWindowInteractor as a XtRenderWindowInteractor. Thanks!

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<div class="post-metadata">

**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [March 20, 2020, 2:16pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/16 "2020-03-20T14:16:21Z")

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We can stick to the newest VTK version with Xt for a while. Thanks.

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<div class="post-metadata">

**Author:** ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Post date:** [March 20, 2020, 2:18pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590/17 "2020-03-20T14:18:46Z")

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> [@Paulo\_Carvalho](#):
>
> Oh… I thought OIV was fairly known int the 3D developer community. Sorry about that.

I’m a build systems guy; I only use VTK and ParaView in as much as I need to debug things usually 🙂 .

> [@Paulo\_Carvalho](#):
>
> So, what’s the point of starting a discussion? Simply take it off and be done with it.

I meant that just because FrobNarRender supports Xt wouldn’t be that influential (to me) for VTK’s suggested support.