Okay... It _is_ Ntrig's fault. Following http://www.wacomeng.com/windows/docs/Wintab_v140.htm, we have:

lcSysExtX, lcSysExtY: Together specify the extent of the screen mapping area for sys­tem cursor tracking, in screen coordinates.

On this 3200x1800 screen, n-trig's wintab driver returns: 1280x720.

This needs a workaround, obviously, but it's just as obviously wrong -- wacom, yiynova, huion and uc-logic provide the correct values. I've contacted n-trig about this.

Here's a special windows build to test on the surface pro 3:

http://files.kde.org/krita/windows/krit ... .79.24.zip

On my device, the offset is gone, but I have a kind of weird problem when pressure exceeds some level the line stops. Please help testing this build on an actual SF3, my hardware is a kind of weird Intel development platform device.!

I'm downloading and will try it on different screen magnifications.
But I have to remark that on my surface even the last build worked correctly at 125% so I don't know how much reliable it'll be.

Ok, tried it at 125, 150 and 200% and the tracking was perfectly fine.
Unfortunately I had to do the test with OpenGl deactivated: I installed just yesterday a new video driver because the old standard one gave me general quality problems on windows and with this one Krita's OpenGl gives me a completely black and unresponsive space where the canvas should be.
Both in this and in 2.8.3.

Thank you for your great efforts in fixing the screen offset. Looks like you were right all along and it was N-trig

Congratulations, the pen pressure on Surface is working better in Krita than Photoshop !!
(I didn't try the version above but the regular one)

Two things would be great :
1) to have bigger icons to be used easily with fingers or pen (especially tools and brush size)
2) to have, like in many other apps in MS Surface (and even the old versions of Photoshop), the eraser selected when you click on the first button of the pen
and to have the size of the brush when you click with the other button

I'm sure Microsoft has everything to gain with quality drawing app like Krita so they could provide some help if we contact them

I never knew about the eraser button, but there's a bug report for that (https://bugs.kde.org/show_bug.cgi?id=341899). I'm currently struggling with actually making the ntrig pen on my device work -- it's an Intel 2:1 development kit, not a regular surface, and I get weird chopped-off lines.

As for the bigger icons and controls, I hope we can figure something out. This is one area where porting to Qt5 should help a lot, because Qt4 isn't really good with hi-res screens.

I contacted microsoft support to suggest them helping you. They are very nice and very easy to join. Maybe if other users of Krita and Surface contact also the support, it could show them there is people interested by Krita and motivate them to improve the compatibility between Krita and Surface?

That would be awesome! I've already tried to contact Microsoft through two or three channels, but they seem to be rather unused to open source projects being all hyped up about some of their hardware and wanting to support it

Mind you, if there's a surface pro 3 here in my house, I'm not sure I wouldn't spend most of my time just doodling...

First button on the n-trig pen is usually the eraser, but I also struggle with bringing up the color/pen popup selector (I believe that is a RT mouse button). It would be great to have that as button 2!

Rob Frydyrck wrote:First button on the n-trig pen is usually the eraser, but I also struggle with bringing up the color/pen popup selector (I believe that is a RT mouse button). It would be great to have that as button 2!

agree with this !

feydk wrote:Congratulations, the pen pressure on Surface is working better in Krita than Photoshop !!
(I didn't try the version above but the regular one)

I'm sure Microsoft has everything to gain with quality drawing app like Krita so they could provide some help if we contact them

That's good to know, I just bought one a few days ago and couldn't get pen pressure to work in Krita, now I know it wasn't just me. Unfortunately the SP3 was taken overseas for an unknown amount of time so I only go a few hours with it and will have to wait for it's return to test it further. If I had it with me I'd contact Microsoft support and promote Krita as a great program that could be loaded onto in-store demo models to demonstrate the pen's graphic abilities, and so it would be worth them sending Krita development a Surface to work with.

Well, I haven't looked into the buttons yet... But we found another gotcha with the n-trig driver, on the intel device: it reports that is has pressure range of 0..255. And then blithely reports pressure between 0 and 1024.

boudewijn wrote:Well, I haven't looked into the buttons yet... But we found another gotcha with the n-trig driver, on the intel device: it reports that is has pressure range of 0..255. And then blithely reports pressure between 0 and 1024.

I believe that the pressure range for n-trig is 0-255. Originally it was thought to be a huge disadvantage vs the wacom's much larger range, but after looking at the real meaning of pressures it turns out to be about the same. (I can explain further if needed.)

djwaterman wrote:That's good to know, I just bought one a few days ago and couldn't get pen pressure to work in Krita, now I know it wasn't just me. Unfortunately the SP3 was taken overseas for an unknown amount of time so I only go a few hours with it and will have to wait for it's return to test it further. If I had it with me I'd contact Microsoft support and promote Krita as a great program that could be loaded onto in-store demo models to demonstrate the pen's graphic abilities, and so it would be worth them sending Krita development a Surface to work with.

Pen pressures works great with Krita. You may need to update your n-trig or wintab driver.