After 4 long years.... (yes, before I ever appeared here )
4 different distros...
3 different major versions of QT...
3 brands of tablet manufacturers...
An insane number of udev / .fdi / xorg.conf tweaks...

I FINALLY have tablet pressure sensitivity in Krita! \o/



It seems that QT 4.5/4.6 were probably the main culprit as I got no luck until I compiled and installed QT 4.7 beta, upon which beautiful, smooth, curvy, tapering lines in Krita were mine at last (no other tweaks needed!).

I have to say... painting in Krita looks *so* much better without artificially uniform line width everywhere. I'd like to take the opportunity to remind people with a working wacom to remember the experience with Krita for most of the world that either:

1. Doesn't have a tablet
2. Has an unsupported tablet (eg almost every brand out there excepting Wacom)
3. Has a version of QT that doesn't properly support their tablet.

The only option these people have to get decent looking strokes with natural looking line-width variation is using the speed curve, which currently seems to need fixes to smoothing and not setting speed to 0 at the start of every stroke.

Anyway, I just wanted to say thanks to everyone who's helped me try things over the years. Special thanks to Boud for helping me pick out a good tablet on eBay without getting fleeced. Krita + working tablet = very sexy indeed.

As a bonus, I just discovered that Blender 2.5 in SVN seems to have fixed their projection painting crasher bug, and that it's now possible to use Krita + Blender's projection paint together for a really nice texturing workflow (just browse to Krita's binary from Blender -> File -> Preferences -> Paths -> Image Editor). No promises, but I'll try and get some kind of video tutorial up soon.

Yeah! ideed it finally does. As a curious fact. A couple of days ago I finally got a wacom tablet, and it didn't wanted to work with krita, I had o pressure sensitivity, Until I tried the Qt4.7, now it's beautiful to have it working the right way A lot of thanks to the developers!

It is worth to note that 4.6.3 that was released a couple of days ago also have the fix.

Interesting thing is that I originally tried qt 4.6.2 with the patch applied to add the fix but that didn't work for me. It was only when I tried QT 4.7 on Arch that it started working. When QT 4.7 (B1) came down through the repo's on Kubuntu it didn't seem to fix anything at all. Then I got some updates on Arch and loss pressure sensitivity in Krita there, too.

*sigh* Anyway, it was nice for the single day that I had it!

Still, I'm guessing that it's now more of an issue of configuration than the previously ubiquitous bugs in QT.

Kubuntiac wrote:It seems that QT 4.5/4.6 were probably the main culprit as I got no luck until I compiled and installed QT 4.7 beta, upon which beautiful, smooth, curvy, tapering lines in Krita were mine at last (no other tweaks needed!).

Hello all, my first post here! I'm new to Krita and new to Linux... I'm using Ubuntu 10.04. Would it be possible for someone to write clear, step by step instructions on what to do to get pressure sensitivity in Krita?

I've had a very positive experience on Ubuntuforums.org where one of the expert members provided step-by-step advice on how to get my Wacom Graphire3 pressure sensitive in Gimp. The advice involved compiling from source, a scary concept for me, but it went without a glitch. Now I'm hoping that it may be possible to achieve the same in Krita.

No need to compile anything. You need to update to Qt 4.6.3

Add this to you package sources:
http://ppa.launchpad.net/kubuntu-ppa/ppa/ubuntu lucid main

Then fetch the updates and install the updated Qt.

Thanks, though the correct procedure for Ubuntu 10.04 is a little different, I got it from Ubuntu Launchpad. After that I installed Krita 2.1.2, which also installed the QT 4.6.3 files. And yes, Krita supports pressure sensitivity on my Wacom. It's a shame though, for my purposes - mostly processing photos - the program is too buggy to be of use. I'll see if I can download the latest version, here's hoping for better luck!

Well, 2.1.2 is indeed really buggy. 2.2 is much better. 2.2.1 will be released this week. However, whether Krita will be fit for your purpose remains to be seen: it is not a photo manipulation application but a digital painting application.

I appreciate it isn't a photo editor. All I really wanted to do with Krita is the initial Levels and Brightness/Contrast processing of 16bit files, before I take them to the 8bit GIMP. I also wanted to reduce colour noise by creating a new layer, blurring it, and setting its transfer mode to Color. Krita offers this functionality, so it shouldn't be a problem. But I was getting all kinds of weirdness in the interface - slow, jerky redraws, sliders that have strange effects, etc. Most disappointing was that the Color layer transfer mode works pretty much exactly as it does in GIMP, incorrectly. It worsens luminance noise, something that shouldn't happen. I suppose both programs use the same or very similar algorithm or programming library for this. There's a discussion about the problem at Linuxquestions.org in the Software section.

Anyhow, I take it Krita is programmed in Qt, which is not a good sign, from what I've read about it. Not only have you to fix Krita bugs, but you're at the mercy of any Qt bugs. And the performance just seems awful. The whole point I sidegraded from Mac to Linux was to get affordable, multi-core speed. But Krita on my 2.6 Ghz 4-core PC is slower than my old Photoshop on my old 1.2 single-core G4.

I can only wish the dev team good luck with their work, and take it on board the program isn't mean for working on large bitmaps like 15MP photos, it is just for painting at relatively small sizes. If Qt is ever abandoned in favour of something faster like C or C++ then I'll try it again. It's a shame, Linux needs a viable, 16bit bitmap editor, and there just isn't one. But all is not lost, I am getting some good results with GraphicsMagick and ImageMagick routines run directly in Gnome.

Cheers!

There is no reason that Krita is slow because of Qt. Almost everything in Krita is written using C++. The code still needs to be optimized in some cases. Newer versions of Krita are usually faster.

If you think that Krita doesn't work correctly in your case please report that as a bug.

This is for version 2.1.2, it might have been fixed in later versions: open a bitmap picture of a decent size, duplicate it into a new layer, bring up the Brightness/Contrast filter and alter the curve. You should be seeing all kinds of weirdness in terms of how the screen updates, the luminance jumping about, the slow response (to the point of seemingly freezing on a 15MP image). But if you get past this point, try to then alter the opacity of this layer by dragging its opacity slider - again, weird luminance shifts and jerky response, if there is a response. The buggyness is complex!

I'm not presently updating to a newer version because when I attempt it from Ubuntu Launchpad, I get dependency issues, beta libraries are required. I simply don't want to run beta software in my Linux system, I'm afraid of screwing things up. I'll wait until Krita works with stable libraries.

In trunk it's better now, though there are still some update weirdnesses. But Dmitry is working on that. One thing though: you don't need to duplicate layers and filter then. You can add filter layers in Krita directly