Bug 438103 - Brush shape irregular at start of stroke
Summary: Brush shape irregular at start of stroke
Status: RESOLVED UPSTREAM
Alias: None
Product: krita
Classification: Applications
Component: Brush Engine/Shape (show other bugs)
Version: 4.4.3
Platform: Compiled Sources All
: NOR normal
Target Milestone: ---
Assignee: Krita Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-06-05 05:14 UTC by sorin
Modified: 2021-09-09 13:04 UTC (History)
3 users (show)

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


Attachments
screen shot showing issue (111.28 KB, image/png)
2021-06-05 05:14 UTC, sorin
Details
Screenshot 2021-06-06 162645.png (58.56 KB, image/png)
2021-06-06 23:28 UTC, sorin
Details
Screenshot 2021-06-06 162304.png (58.92 KB, image/png)
2021-06-06 23:28 UTC, sorin
Details
Screenshot 2021-06-06 164034.png (106.13 KB, image/png)
2021-06-06 23:45 UTC, sorin
Details
Screenshot 2021-06-06 164234.png (59.76 KB, image/png)
2021-06-06 23:45 UTC, sorin
Details
Screenshot 2021-06-06 164301.png (57.60 KB, image/png)
2021-06-06 23:45 UTC, sorin
Details

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Description sorin 2021-06-05 05:14:56 UTC
Created attachment 139014 [details]
screen shot showing issue

SUMMARY
When using any brush with pressure sensitivity controlling size, the brush always starts off with a thick circle at the maximum size possible with those settings (the pressure curve found in the brush settings under "size") soon followed by the actual size determined by the pressure. Basically, every part of the stroke works normally except for the very beginning which has the big blot. 

STEPS TO REPRODUCE
1. use any brush for instance inkbrush 25
2. have the brush settings as preset
3. draw any stroke from any point in the canvas.

my canvas size is 1920 x 1080 at 300 ppi

OBSERVED RESULT


EXPECTED RESULT


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
Comment 1 Ahab Greybeard 2021-06-06 20:20:18 UTC
I don't see that happen with version 4.4.3 running on Debian 10 with a Wacom Intuos  Draw tablet.
A very low pressure start to the stroke gives a very small starting size followed by increasing size with increasing pressure, for brushes with that designed characteristic.

Can you use the Table Tester to check the pen pressure values at the start of a stroke when doing a low pressure start?
Comment 2 sorin 2021-06-06 23:28:57 UTC
Created attachment 139053 [details]
Screenshot 2021-06-06 162645.png

   So the issue is with the very beginning of the stroke, it always
   starts with a big blob and then changes to follow its regular
   pressure. Also, I have the tablet tester but I don't see anything that
   displays pressure sensitivity, just its location in coordinates and
   some value for B. Also, on my device I do not have a blue line as
   stated in the Krita help page, so it may be a problem with my computer
   specifically.
   The left panel of the tablet tester reads:x=#(from 59 to 64 ) y=
   #(from 105 to 20) and b=1(never changes even as i vary pressure with
   my stylus).
   attached are two screenshots of the Configure Krita page with the
   Tablet Tester open, although i'm not sure how helpful they will be.
   For the "S" I had varied pressure, starting strong then growing weak
   at the tip, and for the "l" I had constant pressure.
   side note: thanks for responding so quickly to my bug report, and also
   sorry if I do anything incorrectly when describing the issue, this is
   my first report.

     -------- Original Message --------
     Subject: [krita] [Bug 438103] Brush shape irregular at start of
     stroke
     From: "Ahab Greybeard" < bugzilla_noreply@kde.org[1]>
     Date: Sun, June 06, 2021 1:20 pm
     To: sorin@jayaweera.com[2]

     https://bugs.kde.org/show_bug.cgi?id=438103

     Ahab Greybeard < ahab.greybeard@hotmail.co.uk[3]> changed:

     What |Removed |Added
     ----------------------------------------------------------------------------
     Status|REPORTED |NEEDSINFO
     CC| | ahab.greybeard@hotmail.co[4].u
     | |k
     Resolution|--- |WAITINGFORINFO

     --- Comment #1 from Ahab Greybeard < ahab.greybeard@hotmail.co.uk[3]>
     ---
     I don't see that happen with version 4.4.3 running on Debian 10
     with a Wacom
     Intuos Draw tablet.
     A very low pressure start to the stroke gives a very small
     starting size
     followed by increasing size with increasing pressure, for brushes
     with that
     designed characteristic.

     Can you use the Table Tester to check the pen pressure values at
     the start of a
     stroke when doing a low pressure start?

     --
     You are receiving this mail because:
     You reported the bug.

   

   1. mailto:bugzilla_noreply@kde.org
   2. mailto:sorin@jayaweera.com
   3. mailto:ahab.greybeard@hotmail.co.uk
   4. mailto:ahab.greybeard@hotmail.co
Comment 3 sorin 2021-06-06 23:28:58 UTC
Created attachment 139054 [details]
Screenshot 2021-06-06 162304.png
Comment 4 sorin 2021-06-06 23:44:58 UTC
Created attachment 139055 [details]
Screenshot 2021-06-06 164034.png

   Sorry for sending multiple messages, I just found that when I switched
   my pen API to the Windows 8+ pointer input, the issue changed to be
   the exact opposite. At the start of the stroke it would be small and
   then it would go to the regular settings of the brush, and the Tablet
   tester showed a blue line. When I did varying pressure for the S this
   time, the P value changed, as well as when I lifted up the stylus a
   red line appeared, and when I did constant pressure for the l the P
   stayed at 0.0% and there was no red line. Attached are the
   screenshots. Thank you for you time!

     -------- Original Message --------
     Subject: RE: [krita] [Bug 438103] Brush shape irregular at start
     of
     stroke
     From: "Sorin Jayaweera" < sorin@jayaweera.com[1]>
     Date: Sun, June 06, 2021 4:28 pm
     To: " bug-control@kde.org[2]" < bug-control@kde.org[2]>

     So the issue is with the very beginning of the stroke, it always
     starts with a big blob and then changes to follow its regular
     pressure. Also, I have the tablet tester but I don't see anything
     that displays pressure sensitivity, just its location in
     coordinates and some value for B. Also, on my device I do not have
     a blue line as stated in the Krita help page, so it may be a
     problem with my computer specifically.
     The left panel of the tablet tester reads:x=#(from 59 to 64 ) y=
     #(from 105 to 20) and b=1(never changes even as i vary pressure
     with my stylus).
     attached are two screenshots of the Configure Krita page with the
     Tablet Tester open, although i'm not sure how helpful they will
     be. For the "S" I had varied pressure, starting strong then
     growing weak at the tip, and for the "l" I had constant pressure.
     side note: thanks for responding so quickly to my bug report, and
     also sorry if I do anything incorrectly when describing the issue,
     this is my first report.

       -------- Original Message --------
       Subject: [krita] [Bug 438103] Brush shape irregular at start
       of stroke
       From: "Ahab Greybeard" < bugzilla_noreply@kde.org[3]>
       Date: Sun, June 06, 2021 1:20 pm
       To: sorin@jayaweera.com[1]

       https://bugs.kde.org/show_bug.cgi?id=438103

       Ahab Greybeard < ahab.greybeard@hotmail.co.uk[4]> changed:

       What |Removed |Added
       ----------------------------------------------------------------------------
       Status|REPORTED |NEEDSINFO
       CC| | ahab.greybeard@hotmail.co[5].u
       | |k
       Resolution|--- |WAITINGFORINFO

       --- Comment #1 from Ahab Greybeard <
       ahab.greybeard@hotmail.co.uk[4]> ---
       I don't see that happen with version 4.4.3 running on Debian
       10 with a Wacom
       Intuos Draw tablet.
       A very low pressure start to the stroke gives a very small
       starting size
       followed by increasing size with increasing pressure, for
       brushes with that
       designed characteristic.

       Can you use the Table Tester to check the pen pressure values
       at the start of a
       stroke when doing a low pressure start?

       --
       You are receiving this mail because:
       You reported the bug.

   

   1. mailto:sorin@jayaweera.com
   2. mailto:bug-control@kde.org
   3. mailto:bugzilla_noreply@kde.org
   4. mailto:ahab.greybeard@hotmail.co.uk
   5. mailto:ahab.greybeard@hotmail.co
Comment 5 sorin 2021-06-06 23:45:00 UTC
Created attachment 139056 [details]
Screenshot 2021-06-06 164234.png
Comment 6 sorin 2021-06-06 23:45:00 UTC
Created attachment 139057 [details]
Screenshot 2021-06-06 164301.png
Comment 7 sorin 2021-06-06 23:52:09 UTC
I replied to the email(I forgot to include a part so I used two replies). In them I show images of the tablet tester using the WinTab API (it stayed red) and the windows 8+ pointer input API(constant pressure was all blue and changing pressure had a red stick at the end which connected to the beginning). In the actual program, when I am using WinTab the beginning of a stroke is always big, followed by the actual size determined by the pressure, and when I am using the Windows 8+ API it always starts small and then goes up to the actual pressure that I am using. Thank you for your time!

~ My email is Sorin@jayaweera.com and I had responded to the email I recieved from "Ahab Greybeard" <bugzilla_noreply@kde.org> with a CC sent to ahab.greybeard@hotmail.co.u
Comment 8 Bug Janitor Service 2021-06-07 04:33:37 UTC
Thanks for your comment!

Automatically switching the status of this bug to REPORTED so that the KDE team
knows that the bug is ready to get confirmed.

In the future you may also do this yourself when providing needed information.
Comment 9 Tiar 2021-06-07 10:42:23 UTC
It's a problem with tablet driver, you can reinstall it and see what happens.
Comment 10 wolthera 2021-09-09 13:04:01 UTC
Yeah, this seems to be an issue of the tablet driver reporting the wrong values when using wintab. We cannot touch that code, so you're best off using WinInk