Touch does not work in debian bullseye about beamerpresenter

[stiglers-eponym]

Hi,

The handling of different input devices may be a bit unintuitive. I therefore want to exclude first that this is just a usage issue.

By default, when you click on a button for selecting a pen, this pen is only connected to the input device with which you clicked the button. Thus, when you push the button with your mouse, then your mouse will function as a pen. When you push the button with the stylus, your stylus should work as a pen.

It is also possible (albeit badly documented) to define a button that always selects a tool for the same device or class of devices, independent of the device used to press the button. In the configuration this is possible by adding "device":"all" to the tool definition. Attached you find a configuration file, in which the buttons are adjusted to have this behavior: gui.json.

To debug this problem, it would be simplest if you could use the attached configuration file (you can use beamerpresenter -g /path/to/gui.json). Does the stylus have an effect now? Can you use the stylus to push buttons and does that have any effects?

[saucec0de]

Hi Valentin,

thanks you for such a quick answer.
The hint about the "device":"all" made the stylus work properly in Debian. The cursor continues to look like a mouse cursor (in Xournal++, the cursor changes when I move the pen - not sure if the same should happen for beamerpresenter, though), but now pressing the stylus on the screen makes it draw properly. So, for me, the problem with Debian is solved. (by the way, I am using Debian on a Lenovo Yoga 370).

In relation to the question "Can you use the stylus to push buttons and does that have any effects?"
I can now draw by pressing the stylus against the screen. When I click the button in the stylus, the erasor tool appears, just as before. The difference is that now pressing the stylus against the screen allows me to draw.

However, I have tried also the gui.json that you give me in the MacOS, and I observe a very strange behaviour. Not sure if this issue should be closed (or renamed), but I see some issues in Ventura. The version string of BeamerPresenter that I am using in MacOS is the following:
% beamerpresenter --version
BeamerPresenter 0.2.3 mupdf=1.21.1 Qt=5.15.8

The new issue that I observe is as follows. I start the program with:
beamerpresenter -g gui.json.txt empty.pdf

The empty.pdf file is just used for testing - it is a blank sheet.
When I select the pen in the GUI, I can now draw in MacOS with my stylus (Wacom One CTL-472) - i.e. the stylus works fine.
However, after drawing for the first time (with or without stylus), when I move the mouse, some strange drawings start to occur. I attach a picture of it, so that you can see the issue:

Let's forget about the fact for now that the buttons are too small...
The interesting thing is that this strange behaviour only starts happening after I first select the pen tool and draw something. Before, I can move the mouse and nothing happens. However, after drawing for the first time, its like the pen is stuck in draw mode, and also shows some strange spikes. I also note that this only occurs when I move the mouse. If I move the stylus, this strange stuff does not occur, and the cursor can move freely. As soon as I move the mouse, this stuff happens again. Clicking on the "none" tool allows me again to move the cursor again with the mouse, without strange stuff...

Again thanks a lot for your time and for the awesome program :-)

[stiglers-eponym]

This seems like input events come simultaneously from the mouse and from the stylus. Currently such a situation is not handled correctly. Thus one has to make sure that only one device is used.

The following workaround might help: Replace "all+" with "tablet pen" in the GUI config file (gui.json). Then only the stylus should work.

[saucec0de]

Awesome!
Works like a magic encantation :-)

Thanks again!

[stiglers-eponym]

To help keeping an overview of tools assigned to different devices, I created a widget which can be added to the GUI configuration (gui.json) as {"type": "tools"}. An example can be found in config/gui-interactive.json. This also provides an alternative way of selecting tools. Maybe that helps avoiding the problem of selecting tools per device.