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#86 Pen (N-Trig) input too slow

Manfred Steiner

I am using a Fujitsu Q550 Tablet PC with Windows 7 32 Bit OS. The Pen Input works fine with Windows-Journal.
When using xournal, the pen input speed is too slow, that results in bad looking or not understandable hand-written text,
The PC is using the N-Trig drivers and it seems for me that Microsoft has some better access to the drivers than xournal.
That's my feeling why ther is such a guge performance loss from Windows Journal to xournal.

So it would make sense to spend some time to investigate and fix the root cause for the pen performance problem.

I hope that one of the next Linux distributions will run on the Fujitsu Q550 Tablet PC and the performance will be better if using xournal in combination with a Linux OS.


  • Denis Auroux
    Denis Auroux

    Just to clarify: are you using xournal's Windows port, or xournal on Linux (and if so what distribution)?

    The Windows port of xournal does not have access to the Windows Pen API, for now it's just a simple port of the Linux version; so it merely uses the input data passed on by GTK+, which means basic pointer coordinates (no pressure info) (except when the tablet is a Wacom and the appropriate driver is installed).

    A lot of future work remains necessary on the windows port, though that'll probably restart from xournal++ when it is released.


  • Sample of text, written in same speed/pressure

  • Denis, thanks for response.

    I am using xournal's Windows port. Principially I would prefer a linux system on my tablet pc, but up to now the graphics system is not working and I didn't spend enough time to investigate the rout cause.

    The missing pressure functionality like thickness of a line depending from pressure is not the problem. With Windows Journal every movement of the pen is captured and displayed. With xournal it seems that only 25% of the movement is captured, and therefore the result of written text is very very bad. For me it seems that the pen touchment is not detected well.

    Do you think that it will work better if running on Linux?

    I upload a file with two samples, written in same style (speed and pressure).

  • Denis Auroux
    Denis Auroux

    Given that I don't have an N-trig equipped tablet, and that I don't even have an up-to-date Windows install anymore, I'm not sure I can investigate the issue... Any reports of other Ntrig-based tablet users? (both with Windows-xournal and with Linux)? Do you have the same problem?

    One idea: I'm not sure how the N-trig driver works, but presumably there's a minimum pressure needed to make the pen motion actually count as a mouse click. I believe that Windows Journal knows about pen motions below that minimum pressure while xournal wouldn't have any way of detecting them. Does xournal capture pen strokes better if you write harder on the screen surface, or does it remain more or less the same? If writing harder improves things, see in the driver options if you can change the minimum pressure setting for clicks (so you don't have to write as hard).

    If that doesn't work, there's not much that can be done easily... if the N-Trig driver doesn't report cursor motions consistently when the pen moves, the only two options are (1) changing the N-Trig driver, or (2) rewriting xournal so the windows version talks to the Windows Pen API to get better input data.


  • I tried to write with more pressure (it makes it not easier to write). The result is a little bit better than before but not really good. If xournal only captures mouse-movement with pressed left mouse-button, the result is understandable. To reduce mistakes (i.e caused by unwanted touchments to the panel) they have implemented some blocking principals, i.e. if you start to touch somenthing you have to touch app. 0.3s-0.5s until touchment is accepted. This explains why xournal somentimes doesn't store anything for this time period. Up to now I have not found any ways to configure the N-Trig drivers motre in details (but that's typical for Windows systems...)

    So it seems that good results are only achiveable if xournal is using the special WinAPI functions to track mouse movement when writing.

    So at the moment I can use xournal for drawings and a small portions of text but not as a "Notepad". So I am looking forward for a new improved version of xournal.

    I am sure that xournal has the potential to capture market share from Windows Journal because functions like layer-management and pdf-export are a real benefit. At the moment Windows Journal is not able to generate a pdf from a note with some highlighted marks. Only the workarround via xps-printings works, but generates huge pdf-results (1.3MB for one page instead of 17kB using xournal).

    Thanks for information..