Jelly effect when writing/drawing with a pen on WinUI ink canvas

[msbrunoalves]

Describe the bug Writing/drawing on WinUI applications has a very noticeable jelly effect that affects the confidence of using the pen to write or draw. I am using a Wacom Intuos S Tablet. It's an issue that has been reported for years and nothing has been done about it except saying "use the old OneNote, that one doesn't have the issue". https://www.reddit.com/r/Surface/comments/41kxd0/can_you_disable_ink_smoothing_in_onenote/cz6yqc0?utm_source=share&utm_medium=web2x&context=3 This reddit post is 4 years old and even had an alleged person on the "OneNote Ink team", but nothing has changed. It is especially noticeable on OneNote for Windows 10 because it's a 2 step process where it's jelly while you're writing and a final smoothness is applied when you let go of the line. However it does happen in all apps that use WinUI Ink Canvas (Except Microsoft's Whiteboard).

Steps to reproduce the bug

• I can only speak for my Wacom Intuos S Tablet, but there have been reports on the same issue with surface devices. It does not happen when using a mouse, only a pen.

• On any application that uses the WinUI canvas for drawing, draw or write lines with many curves at different speeds, the jelly effect will be present.

OneNote for Windows 10 is the worst offender , but any UWP or WinUI app except Whiteboard should have the same issue, even XAML Controls Gallery on the "InkCanvas" or "InkToolbar", which has lead me to believe this is in fact a WinUI issue.

Expected behavior The expected behaviour is applying smoothness in a seamless instant way like Microsoft's Whiteboard or Wacom's Bamboo Paper app does, it still writes smoothly but does not have any jelly effect and does not affect writing/drawing accuracy.

Screenshots (Video) https://www.dropbox.com/s/hiv1az28ilzwibm/2020.10.30-20.51.mkv?dl=0 I have made a video demonstrating the issue:

• On Microsoft Whiteboard it's all very smooth and instant, feels very natural.
• On old OneNote it's natural and instant but draws more jagged sharper lines and has no support for pressure sensitivity.
• On "new" OneNote for Windows 10 it's all very jelly feeling and even has a final smoothing effect when you let go of the line.
• On XAML Controls Gallery It's better than OneNote for Win10 but is still jelly on curved lines, hard to see on 30fps video but easy on the screen (observe how the line moves when I draw the long line at the end).

Version Info OneNote for Windows 10 - 16001.13127.20190.0 XAML Controls Gallery - 1.2.16.0

Windows 10 version	Saw the problem?
Insider Build 19042.608)	Yes
May 2020 Update (19041)	Yes
November 2019 Update (18363)	Yes
May 2019 Update (18362)	Yes
October 2018 Update (17763)	Yes
April 2018 Update (17134)	Yes
Fall Creators Update (16299)	Yes
Creators Update (15063)	Yes

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

Additional context This smoothing is not applied by the pen itself, I have no issues with Whiteboard, Bamboo Paper, Adobe Photoshop, Gimp or Krita, just WinUI Apps (not sure if Whiteboard is WinUI).

[jonwis]

@feisu can you route appropriately? If it's a known issue, paste an http://task.ms/yyyyy link so we can track it.

[feisu]

Sure. I can definitely help route this issue to windows ink team. The smoothing effect is applied in the inking layer.

[msbrunoalves]

Hello, I wanted to add some more information to this issue.

I mentioned that "It is especially noticeable on OneNote for Windows 10 because it's a 2 step process", I think the cause of the 2nd part of this issue is that OneNote seems to be "compressing" the drawn line to use less data, because when you let go of the line it doesn't get smoother, it gets more square (instead of a perfect curve, it becomes a bunch of small straight lines), so that may be why that part does not happen on other UWP apps.

Should I report this as OneNote problem somewhere else also?