Targeting Linux for touchscreen OA project

GrahamRA · Post by **GrahamRA** » Tue Jun 22, 2021 10:39 am

Hi there, I've been having a bit of trouble deciding on a way to approach the decision of a target OS for a project we're working on and I wanted to get a bit of community input on the issue.

We're developing a touchscreen OA project which, expecting to move later to Red Hat Enterprise Linux, we'd been running on our test rig using CentOS 8 with KDE. One of the requirements for our product is it should provide a virtual keyboard for text entry.

Now I realised from the OA docs that the default desktop environment of GNOME does not support the virtual keyboard, what I'd missed however is that Red Hat Enterprise Linux does not offically support KDE—so I feel I'm at a bit of an impasse, also realising that WinCC OA's support for SUSE (which supports KDE) ends with v3.17. Is there a route for official support with OA and a KDE-based Linux which would support the necessary touchscreen features we need?

With thanks,
Graham

Edit: I should've specified this is intended to run in kiosk, single-application, mode; and I've realise I'm overcomplicating the matter by including any window manager/desktop environment when all that's needed is an entry in the /usr/share/xsessions/ directory with the right config to launch the UI—no need for GNOME or KDE.

leoknipp · Post by **leoknipp** » Fri Jun 25, 2021 4:10 pm

If you run the UI in kiosk mode, do you still have a problem?
Did you run the UI with the -touch option?

Best Regards
Leopold Knipp
Senior Support Specialist

GrahamRA · Post by **GrahamRA** » Tue Jun 29, 2021 4:14 pm

Hi Leopold,

I think I may not have been clear, I wasn't strictly having a technical issue but more an admin issue.

We'd been expecting to target Red Hat, which only supports Gnome, not KDE. But the WinCC OA touch keyboard doesn't work under Gnome. My question was basically if there's a Linux distro we can get commercial support for which supports KDE. Suppose there's always Windows!

In the meantime however, I realised I could skip the whole desktop environment issue and run the application directly (with neither Gnome nor KDE) by defining a custom x session which just runs the WCCOAui manager for the project.

As a note, I did find an issue with focusing the cursor into text boxes in the application while using the touchscreen when running the application directly. I got around that by using the KDE window manager kwin.

Basically I have these files:

/usr/share/xsessions/hci-app.desktop

Code: Select all

[Desktop Entry]
Name=HCI Application
Exec=/opt/run-hci.sh

/opt/run-hci.sh

Code: Select all

#!/bin/sh

kwin &
/opt/WinCC_OA/3.17/bin/WCCOAui -proj PROJECT_NAME -p vision/login.pnl
logout

Additional config goes into /etc/gdm/custom.conf too.

Slight tangent to my original problem but if anybody else is having trouble with so-called "kiosk mode" then hopefully this helps.

leoknipp · Post by **leoknipp** » Mon Jul 05, 2021 12:13 pm

The information which operating systems and Desktop Environments are supported you can find in the WinCC OA Documentation.
According to the documentation in WinCC OA 3.17 GNOME and KDE are supported.

Best Regards
Leopold Knipp
Senior Support Specialist

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