Bug 496075 - When using a pen tablet, brush pressure is not available and coordinates are sometimes incorrect.
Summary: When using a pen tablet, brush pressure is not available and coordinates are ...
Status: RESOLVED NOT A BUG
Alias: None
Product: krita
Classification: Applications
Component: Tablets (tablet issues are only very rarely bugs in Krita!) (show other bugs)
Version: 5.2.6
Platform: Other Microsoft Windows
: NOR normal
Target Milestone: ---
Assignee: Krita Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-11-11 05:56 UTC by microsunrain
Modified: 2024-12-14 20:38 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
BrushPressureIsNotApplied.mp4 (3.76 MB, video/mp4)
2024-11-11 05:56 UTC, microsunrain
Details

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Description microsunrain 2024-11-11 05:56:45 UTC
Created attachment 175722 [details]
BrushPressureIsNotApplied.mp4

SUMMARY
When using a pen tablet, the brush pressure and coordinates are wrong.
Please watch the attached video.
When I set the brush pressure in the brush editor and draw a curve on the scratchpad, I get a curve with brush pressure ignored at the tablet pointer coordinates or a curve with brush pressure applied at odd coordinates.
Other drawing software running at the same time will draw the curve with the brush pressure applied correctly.
In addition, sometimes, when drawing on canvas with a pen tablet, the drawing is drawn at odd coordinates.
The Tablet Input API in the Tablet settings in Configure is set to WinTab. If this is changed, brush pressure is not applied.

STEPS TO REPRODUCE
1. Select ink-3 Gpen in the paint layer.
2. Open the Brush editor and check Size and Pressure.
3. Draw on the scratchpad with a pen tablet.

OBSERVED RESULT
Brush pressure is not applied.
Lines are sometimes drawn at odd coordinates.

SOFTWARE/OS VERSIONS
OS
 Windows 10(64) Pro
Krita
  Version: 5.2.6 (git ab3502b)
Qt
  Version (compiled): 5.15.7
  Version (loaded): 5.15.7

Thank you for developing this wonderful software.
Comment 1 microsunrain 2024-11-11 06:02:41 UTC
ADDITIONAL INFORMATION
Tablet: Wacom Intuos 4
Comment 2 Dmitry Kazakov 2024-11-11 09:58:05 UTC
Hi, microsunrain!

Could you try the following things for me:

1) Switch Krita to WinTab API. Close Photoshop or any other software that can use the tablet. Then start Krita and check if the pressure comes back.

2) Go to Wacom Tablet settings. Enable WinInk API there (there is a separate checkbox for it). Switch Krita to WinInk mode, restart Krita. Does it recover any kind of pressure sensitivity?

Please tell if these steps change anything for, so I could possibly look further into the problem
Comment 3 microsunrain 2024-11-11 14:28:30 UTC
Hi Dmitry,

Thank you for your comments.
As you can see in my summary, the problem occurs when using the WinTab API.
By the way, after much testing, it turns out that the problem is caused by Krita not recognizing the screen resolution correctly.

The explanation.
I am using the following two LCDs
LCD1: DELL S2721DGF Resolution: 2560 x 1440
LCD2: Mitsubishi RDT232WX Resolution: 1920 x 1080

The Advanced Tablet Setting in Tablet settings is “Use information provided by tablet” by default, and the values at that time were as follows.
Width 4480px X offset -1920px
Height 1440px Y offset 0px
This was changed to “Map to custom area” and the values were changed as follows
Width 2560px X offset 0px
Height 1600px Y offset 0px
If I set the resolution to 1440px, which is the vertical resolution of LCD1, I cannot get the correct coordinates. I tried manually changing the value repeatedly and found that the drawing position and cursor matched at 1600px.
Why it works well with the value of 1600 is completely baffling.

Behavior of the brush pressure when the mapping of the drawing area is changed in Wacom's tablet properties.
Case1. full screen or LCD2: does not work.
Case2. LCD1: It works.
However, in both cases, the correct coordinates can be drawn.
As for Case1, I tried various values for each item in the Advanced Tablet Setting, but it did not work.
Finally, I decided to stretch Krita's Window to two LCD screens and display its drawing area on LCD1.

Personally, I have solved the problem, but it is a bug for Krita and I hope it will be solved.

Thank you.
Comment 4 Bug Janitor Service 2024-11-12 03:46:49 UTC
🐛🧹 Thanks for your comment!

Automatically switching the status to REPORTED so the team can perform further triage.

In the future you may also do this yourself when providing needed information.
Comment 5 microsunrain 2024-12-10 11:55:12 UTC
Hi Dmitry,

I have found a new problem related to this bug and am reporting it.
Even with the previous solution, the pointer coordinates are incorrect when using the Wacom tablet's PRECISION mode together.
I tried adjusting the tablet settings in Krita, but could not solve the problem.
Therefore, I am now using Krita without that precision mode.

Thank you.
Comment 6 microsunrain 2024-12-14 20:38:00 UTC
Hi Dmitry,

I updated my tablet drivers and all problems are now resolved.
I thought it was a problem with Krita, since several other painting software I use did not have the problem, but it was a driver issue.
I am sorry for the trouble.

Thank you.