#12 Use touch gestures to scroll w/ stylus

[Thomas Nield]

I am using Xournal with a Surface Pro 3 running Linux Mint 18. Awesome work! Surprised it works so well out-of-the-box with the surface-linux driver. Is it possible to scroll with a two-finger touch while using the stylus?

[Denis Auroux]

Multi-finger gestures can't be handled by xournal for technical reasons with the current technical architecture (the GTK2 library we rely on is too old), so for now your only hope for a two-finger gesture would be if your graphical environment (gnome, KDE, ...) has support for such gestures at system level and converts them into scroll events for the application.

However, assuming your touchscreen and stylus are distinct X input devices (which I think should be the case on at least some versions of the surface pro?), you can do one-finger scroll while drawing with the stylus -- this is what I have configured on my thinkpad yoga. Run "xinput list" in the terminal to see if there are indeed separate touchscreen and stylus devices.

If so: in xournal,
1. Options -> Pen and Touch -> Designate as touchscreen...
2. select the touchscreen device in the dropdown list
3. enable Options -> Pen and Touch -> Touchscreen as Handtool

Touchscreen should then scroll (with one finger), while the stylus should continue to draw normally. Let me know if this works for the Surface Pro, or if there aren't separate devices.

If you are using gnome and the system becomes unresponsive when you use touch+stylus at the same time, you may need to install some utility to disable the touchscreen at system level when the pen is on the screen, eg xnohands.

Denis

[maenujem]

Hello Denis,

I'm using a HP Spectre X360 with Ubuntu and Xournal is one of the most useful apps for use with the touch screen (especially to simulate overhead projector writing and annotating PDF).

When configuring "SynPS/2 Synaptics TouchPad" as designated touchscreen as described above, then I can use the touch pad for scrolling and the pen (and hands!) for drawing.
Using xinput -list and evtest show me that "ELAN2514:00 04F3:259B" reacts on touch/finger only and "ELAN2514:00 04F3:259B Pen" reacts on pen touch only. When setting this "ELAN2514:00 04F3:259B" as designated touchscreen, it is automatically set to "ELAN2514:00 04F3:259B Pen" when checking the settings afterwards and thus it does not separate pen touch (for drawing) from finger touch (for scrolling).

Any idea what I could try to have no drawing with the finger/hand and be able to easily scroll without changing the tool manually?

Kind regards,
Manuel

[Denis Auroux]

What does the line touchscreen_device_name=... in your .xournal/config
contain? Does it say "Pen" at the end of the device name or not?
If it does, edit the .xournal/config file in your text editor to remove
" Pen" from the end of the line and see if it works better.

If the device name in the config file doesn't include "Pen" but both
devices are treated as touchscreen by xournal, then you probably have an
old version of xournal -- the behavior used to be that any device name
containing the name of the touchscreen device would be treated as
touchscreen; because of exactly the problem you are encountering this
was changed to require an exact match.

Are you using the latest version (0.4.8.2016, or equivalent patched
0.4.8, including commit [48f94d] "test ui.device_for_touch as exact
match instead of substring of device name" of Sept 1, 2014) ? I haven't
kept track of what patches to 0.4.8 are included in the Ubuntu package.
Perhaps try downloading the code from sourceforge (either the tar.gz of
version 0.4.8.2016 or the current git code base) and compiling?

Denis

[maenujem]

Thanks for your instant reply.

According to your description I do not have the latest version. I have 0.4.8.
I've downloaded the latest source but I've not been able to run autogen.sh successfully: there are missing things on my system (16.04 LTS) and I don't know how to fix these as they do not seem to be in standard distro:

**Error**: You must have `glib' installed.
E: Unable to locate package glib
https://ftp.gtk.org/pub/gtk/3.12/ contains some .xz-File -> ?
E: Unable to locate package gtk2-devel
E: Unable to locate package libgnomecanvas-devel
E: Unable to locate package poppler-glib-devel

Regards,
Manuel

[Denis Auroux]

You should install the packages called libglib2.0-dev, libgtk2.0-dev,
libgnomecanvas2-dev, libpoppler-glib-dev, and any dependencies for those
using apt-get (perhaps also libgdk-pixbuf2.0-dev, libcairo2-dev) in
order to be able to compile xournal. (In general ubuntu seems to call
the package containing development for a library named X "libX-dev", so
repeat with whatever is still missing after this).

Denis

[maenujem]

Thanks for the help! Now it did compile fine and xournal behaves as expected and saves my day :)