GTK BUG: pointer shifted relative to tablet pen position

Bug #166919 reported by Zeimusu-users on 2005-09-04
This bug affects 3 people
Affects Status Importance Assigned to Milestone

Bug Description

In a nightly build from Sept 3rd the mouse position is
wrongly detected when the mouse is in the canvas area.

I am using a wacom intuos 2 tablet, with latest wacom
drivers. The position of the mouse on the screen, and
the detect position shown by the claret marks in the
rulers is different. The problem seems to be related to
mouse movement. If I move the mouse quickly the
detected position doesn't keep up with the mouse. If I
move the mouse slowly the detect position moves in

This doesn't seem to affect other elements of the ui; I
can click on toolbar buttons. Only the canvas area is

In the attached file the drawing position is separated
from the mouse pointer. (The mouse pointer has been
drawn by hand, but does show the true position of the

This problem does not occur in the 0.42.2 release. It
does occur in an august 30th build.

Zeimusu-users (zeimusu-users) wrote :

This bug does not appear to affect a computer with a regular
mouse. (Sept 09 build) So it appears to be related to the
wacom tablet. Updating summary.

Popolon2 (popolon2) wrote :

I use tablet and don't have this bug with any cvs version
I'v tested (from august to today), verify than you use
screen mode in input configuration.

Then verify than your stylus is really detected by X11 as
stlylus, else it will be used as mouse, you will have some
bugs with coordinates limits, and the pressure will not be
managed. Try the Xidump given with linuxwacom to be sure of

Zeimusu-users (zeimusu-users) wrote :

Reconfirming bug on a september 22 zip build, on Windows XP
(Home Japanese)

Popolon's comments suggest that this is a windows only bug,
and does not affect linux builds. It also only affects
tablets when they are used with the mouse, not the stylus
(see below)

More details on behaviour:
Two pointer positions seem to be detected: A correct
position and a buggy one. When drawring with the free hand
or bezier tool, only the buggy position is used. With the
rectangle tool and other object drawing tools, the buggy
position is used for the starting point of the rectangle,
the true position for the opposite corner. As a result,
clicking with the rectangle tool doesn't produce a very
small rectangle with opposite corners in the same
positition. It makes a large rectangle with corners in the
true and buggy position.

Using a pen, not a mouse, on the table produces good
results. The postion of the pen is always correctly
detected and matches the position of the pointer on screen.

It seems this regressed around the time that pressure
sensitivity was introduced. Builds from the start of August
don't show this bug.

A possible interpretation of this is that inkscape is
querying the tablet at a low level for some operations but
is not doing so correctly and is interpreting the mouse as a
stylus. The buggy position is the position that would be
detected if the pad was in pen mode.

Zeimusu-users (zeimusu-users) wrote :

I forgot to mention, The "wacom tablet puck" input device.
as reported to the in the file->input devices menu is in
"screen" mode. the X axis is 1, and the Y axis is 2. These
look reasonable to me. I haven't changed them. As I have a
windows build I don't have X11, so I can't follow the other

Zeimusu-users (zeimusu-users) wrote :

Present in 0.43 preview release.

The File->Input devices dialog is a little suspicous. It
reports as available input devices

That is it finds two puck, pens and erasers. However the
wacom tablet doesn't have a conventional puck. This may just
be a semantics, or it may indicate an issue with how the
mouse is being detected.

If this is a gdk problem which can't be fixed here the input
device code should be built only for linux and mac

Zeimusu-users (zeimusu-users) wrote :

See also bug 1335301

Zeimusu-users (zeimusu-users) wrote :

A couple of notes. It is possible to set the mouse to pen
mode for inkscape only, which makes inkscape usable, but it
makes changing between inkscape and other applications
frustrating. It is also rather uncomfortable to use the
mouse as a pen.

The checkin that caused this problem was

Jamesots (jamesots) wrote :

I'm getting a very similar problem on SuSE Linux with
Inkscape 0.43. I usually use a dual-head system, but I also
get a problem when only using one display, so describe
both. I have a wacom graphics tablet.

Single Head
Circles and Beziers are drawn correctly at the right place.
Rectangles don't appear at all when I try to draw them.
Once a circle or line is in place, I can use the node tool
to select a node, but then I can't move it.

Dual Head
When inkscape is on the left hand screen:
I can draw lines and circles, but they appear approximated
105px lower and 5px left of where I try to put them
(physically on the screen, not in SVG co-ordinates). When I
try to draw a rectangle I get a rectangle with it's top
right hand corner at the mouse location, with a height of
around 160 units and a with of around 10 - although it
varies slightly each time. I don't get a chance too drag
out a size - the rectangle appears immidiately. I can
select items, and point to their handles, but when I try to
move them I end up selecting something about 160px lower
and 10px left.

Right hand screen:
Rectangles appear 310 tall and 4020 wide, or thereabouts.
Circles and lines appear 4020 pixels to the left of where I
draw them and 310 below.

Gimp has no problems with my tablet. Input devices are all
set to 'Screen'.

Bug Importer (bug-importer) wrote :

See similar bug in GIMP for additional info and suggested fix.

- Ted Shaneyfelt

Zeimusu-users (zeimusu-users) wrote :

The patch
provides a workaround for this. The tablet pressure
sensitivity can be disabled with inkscape preferences.

I'm marking this as 'Later' and setting the priority to one.
There is little further progress possible unless gdk is
fixed. I'm also assigning to kidproto, as the person who
applied the patch.

Originator: NO

also, for me this is on Kubuntu, so it's cross platform

Originator: NO

For me this is triggered not by the relative/absolute mode but by the TopX
and TopY options in xorg.conf being nonzero. I have to have them at zero if
I want to use tablet.

ScislaC (scislac) wrote :

Originator: NO

In Inkscape SVN (April 09, 2007) and with Ubuntu Feisty 7.04 I cannot
reproduce this bug.

ScislaC (scislac) wrote :

Originator: NO

To elaborate more...
Ubuntu Feisty - ver 7.04 - ver 7.2
Inkscape - ver SVN 04/09/2007
Wacom-tools - ver
Gtk - ver 2.10.11

I set my topx & topy in xorg.conf to 9000, so it was noticeable that the
settings took for the dimensions, but I don't get the incorrect behavior
that others do.

David Császár (p5) wrote :

i'm on win xp tpe 2005 and depending on the pen position on the screen the shift is about +/- 10px for me.
the patch is not working in the current dev 0.46.
see Bug #175398.

btw: i'd like to see the option disabling pen x/y, but keeping pen pressure.

I'm also having this problem. I'm using Inkscape 0.36dev+devel, built Jan 10 2008 in Windows Vista. Before this, I used an older version of Inkscape in Windows XP and had the same problem.

+ Pen stylus is working fine
- Wacom Mouse (sometimes called "puck", but it really looks like a normal mouse) does not even close to where the mouse pointer is in screen (same problem as everyone above has)
+ If i switch the mouse to pen-mode (i.e. absolute positioning), it also works in Inkscape.

But: It is a paint to use the mouse in absolute positioning mode! Especially so with multiple monitors...

So, please please fix relative Wacom positioning in Inkscape! I love Inkscape, but this problem is driving me nuts.

David Császár (p5) wrote :

this probably cannot be fixed in inkscape.
see comment 10 for the gtk bug causing this issue.

available workaround in inkscape is turning tablet features off - but you'll lose pressure.

maybe inkscape could add an extended workaround: see my comment 16.

Changed in gtk:
status: Unknown → Confirmed
zeimusu (james-kilfiger) wrote :

Yes there are a number of workarounds:

* You can disable the tablet features (inkscape options->mouse), but you'll loose pressure sensitivity.
* You can make the wacom tablet work in "absolute" mode with the mouse. You do open the wacom tablet driver control program, add inkscape as a new application and set the mouse to work in absolute mode. But using a mouse in absolute mode, even for one application, is a pain in the neck.
* You can use a separete mouse instead of the tablet mouse, but it can be a nuisance to have to change mice just for one application, your other mouse probably isn't as good as the wacom one, and swapping mice like this has lead to crashes for me.

Nothing perfect, and the bug lies with GTK <>

ScislaC (scislac) wrote :

Since this is a GTK bug and not fixable in inkscape, I marked as invalid for inkscape.

Changed in inkscape:
status: In Progress → Invalid
Changed in gtk:
importance: Unknown → Medium
Changed in gtk:
status: Confirmed → Expired
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