How do show a screen on Windows10 when in control?

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JonathanS
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How do show a screen on Windows10 when in control?

Post by JonathanS »

I was reviewing UltraVNC and before Windows 7/10 you could (when you take control) bring up a screen - something like a PLEASE WAIT MAINTENANCE IN PROGRESS with a picture (or something - does not need to be fancy) - but it seems to have been tied to functionality which no longer works for Windows10? Is this correct? Is there no way with Windows10 to show some customer screen or images or message? The only options found so far are to leave it as-is (so the user sees the maintenance) or to blank it completely (where the user wonders if the monitor died)!

Any help, feedback, or suggestions would be appreciated.
Thanks,
Rudi De Vos
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Re: How do show a screen on Windows10 when in control?

Post by Rudi De Vos »

Sorry, win10 doesn't have a layer that you can exclude for capturing.

The latest versions of ultravnc have the extend desktop with virtual a displays.
Local 1 screen, remote 2 screens
If you work on the second it's invisible and you can show some message on 1
JonathanS
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Re: How do show a screen on Windows10 when in control?

Post by JonathanS »

This response is very interesting and promising - and it may resolve much of my concerns if I am understanding it correctly. In Windows XP/7 we used a VirtualDisplay Adapter (3rd party SW) which created a 2nd display (virtual) and we would VNC to that screen (worked like a charm for decades) - however with Windows10 we were no longer able to use our VirtualDisplay Adapter (not supported) and were forced to plug in a VGA/DVI dongle to have Windows10 create the virtual display (and this is costly) so instead we put everything on the physical primary display and this introduced two big problems:
- We can no longer put our PLEASE WAIT screen on the physical screen (because that is where we now VNC)
- We need to disable INPUT (as you noticed from my other post) because now the user can interfere where they could not before (as it was all on a virtual display hidden)

With that background I am very interested in what you are saying about an EXTEND DESKTOP with a VIRTUAL DISPLAY - it sounds like what we had for Windows XP/7 in the past but instead of using a 3rd party SW Virtual Adapter not UltraVNC is able to do it for us? Do you have any more details or documentation on this? What version was it introduced in?

Thank you very much for all the feedback and support!!!
JonathanS
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Re: How do show a screen on Windows10 when in control?

Post by JonathanS »

Subsequently - doing some research about the Virtual Display you mentioned - can it be persistent (always there) so we can move windows/applications to it at boot of operating system (Windows10) and VNC to it when needed or does it only get create upon connect of the VNC Client (and each time we would need to move the windows we need over?).

We are using the discussion (here) as a reference:
https://forum.ultravnc.net/viewtopic.php?f=77&t=36842
Rudi De Vos
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Re: How do show a screen on Windows10 when in control?

Post by Rudi De Vos »

Download bin zip.
extract UVncVirtualDisplay64
Using the device manager->display adapters->add legacy hardware->and select the inf from this folder.
When i remember correct, then it was installed permanent.
We had a lot of trouble to make it act as an usb connected screen that plugin on viewer connect.
Having an invisible screen isn't handy when a part of the app opens on it :)

Only the supported sizes are limited as the viewer normal pass the correct desktop size to the driver.

Introduced 1.3.0 but you need 1.3.2, to many viewer bugs between 130 and 132
JonathanS
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Re: How do show a screen on Windows10 when in control?

Post by JonathanS »

While the approach of the UVncVirtualDisplay64 solved a great many problems it requires a later version of Windows10 then most of our applications run on - meaning we have a sizable deployment on Win10 1603 which does not support the virtual display (1903 and above) - which means we are back to the initial problem when someone takes control using UltraVNC the user see either what they are doing (and if this is ADMIN work that's bad) or a blank screen (which they think means something went wrong, they reboot or press the screen or, etc....) ...

Given that it has been 9-months and a few new revisions of the product since then - I wanted to float this back up in the forum and see if anything was introduced in these later versions to add some kind of support OR if anyone else has encountered and solved the issue? We just need to show a screen to the user when someone has taken over asking them to PLEASE WAIT ...
Rudi De Vos
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Re: How do show a screen on Windows10 when in control?

Post by Rudi De Vos »

This is fixed, a screen is now possible without using the virtual driver.
Like it was on windows <= 7
It's one extra line of code.
JonathanS
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Re: How do show a screen on Windows10 when in control?

Post by JonathanS »

This is FANTASTIC news - can you clarify a few things:
- Does it have any dependencies on the version of Windows10? My deployment is still 1603 (old) and not at 1903 or the latest 21H2; is this something Microsoft re-introduced support for in a later version (which won't help me) or something that works in the older OS versions also?
- When was this introduced (which version?)
- Is this 1-line of code something we can port to v.1.2.1?
- How do we ENABLE the feature
- How do we determine what to SHOW on the screen?

Won't lie - this is really exciting and amazing stuff!!!
Chris_L
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Re: How do show a screen on Windows10 when in control?

Post by Chris_L »

After examining the latest source code 1.3.7 dev-2, the new layered windows feature requires a call to:

Code: Select all

SetWindowDisplayAffinity(hwnd, WDA_EXCLUDEFROMCAPTURE);
where WDA_EXCLUDEFROMCAPTURE is defined as (from https://docs.microsoft.com/en-us/window ... ayaffinity)

The window is displayed only on a monitor. Everywhere else, the window does not appear at all.
One use for this affinity is for windows that show video recording controls, so that the controls are not included in the capture.

Introduced in Windows 10 Version 2004. See remarks about compatibility regarding previous versions of Windows.

Starting in Windows 10 Version 2004, WDA_EXCLUDEFROMCAPTURE is a supported value. Setting the display affinity to WDA_EXCLUDEFROMCAPTURE on previous version of Windows will behave as if WDA_MONITOR is applied.
Rudi De Vos
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Re: How do show a screen on Windows10 when in control?

Post by Rudi De Vos »

Correct,
See also viewtopic.php?t=37482

It default to a black screen on older versions.
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