Pinch to zoom gesture not working sometimes

[Loki@99]

Hi,

There is an issue with the pinch to zoom gesture.

Steps to reproduce
1. Pinch to zoom in a page on screen
2. Draw something with the pencil tool using a stylus and rest your hand edge palm on the screen for about 5 seconds after drawing.
3. Pinch to zoom out

Bug
It's very random but sometimes first pinch gestures actions will not work.

Maybe it's related to the finger touch not registering when making dots I mentioned in the pencil abnormal spikes topic.

Maybe T#6354 wasn't completely fixed.

Thanks for investigating,

[Daniel - PDF-XChange]

Hello, Loki@99

I have been testing this very carefully and so far have only been able to reproduce the issue in the situation where one of the other fingers on my hand are left touching the screen as well, interfering with the pinch gesture. Can you try again and ensure that you have not mistakenly let one of your other fingers touch the screen some distance away from the "palm area" windows is preventing input inside of?

Kind regards,

[Loki@99]

Hi Daniel,

As I said, it's a very random bug and I'm not even sure what are the real steps to reproduce it.
I will do some further investigation and post here.

Btw, I noticed tickets you created for my other recents previous posts.

Thanks always for your support,

[rakunavi]

Hello Loki@99,

It is possible that the touch operation was locked when drawing with the stylus and the subsequent pinch operation was ignored. The following comments assume that you are holding the stylus with your dominant hand and pinching with the opposite hand.

As far as I know, unless both of the following two conditions are met, the application should assume that you are trying to draw with the stylus and ignore the pinch operation in Step 3

1. The pen tip must be completely off the screen.
2. After drawing a line with the stylus (i.e., after the pen cursor disappears), the pinching hand must be at least about 0.5 seconds away from the screen.

This should apply not only to PDF-XChange Editor, but to any Windows application that uses a stylus. As far as I know, Drawboard PDF and OneNote have the same behavior as PDF-XChange Editor.

Regarding the first condition, simply having the pen tip not physically touching the screen does not satisfy the condition. The pen cursor must disappear. If the pen cursor display is disabled in the Windows settings, enabling it will make it easier to identify the situation. Although there are some differences among devices, the pen cursor should appear even if the pen tip is about 1 cm away from the screen. Therefore, please make sure that the pen cursor disappears from the screen when you place your dominant hand on the edge of the screen. Is the pen tip unconsciously at a distance close to the screen?

Regarding the second condition, for the lock to be released, the pinching hand must be once off from the screen. Even if the hand is off the screen, the lock will not be released if the time is too short, such as 0.1 second. Do you ever leave your pinching hand on the screen all the way from step 1 to step 3? The second and subsequent pinch operations probably responded because after the first pinch operation, the pinching hand left the screen even momentarily, thereby satisfying the second condition and releasing the lock.

I am not particularly familiar with stylus or touch application development, so please forgive me if my comments are off the mark.

Best regards,
rakunavi

[Loki@99]

Hi @rakunavi

Thanks for your input.

Yes, I also have that issue in OneNote.

Regarding the first condition, simply having the pen tip not physically touching the screen does not satisfy the condition. The pen cursor must disappear

I have the stylus tip cursor disabled in windows cause I find it quite distracting.
I enabled it in windows settings and noticed that indeed the cursor must disappear before the pinch gesture can be triggered.

Regarding the second condition, I'm not sure.

Kind regards,

[Daniel - PDF-XChange]

Hello, Loki@99

I have still been unable to reproduce the issue unless I am keeping my palm on the screen while trying to pinch and still holding the pen (which is surprisingly difficult). In the cases where I do "seem to" reproduce the issue, I have always found that it is caused by a third "touch point" existing beyond my palm, usually because of the tilt of my hand while holding the stylus. This is irregardless of whether I am using my other hand, or the stylus holding/palm rest hand directly.

As such, I am not sure I can classify this as a bug, or just intended handling caused by windows touch functionality, and a slight "fringe use case".

Kind regards,

[htsmi]

I am experiencing a similar issue on my Thinkpad X13 Yoga Gen 3. It seems that there is a delay after using the pen where I can't pinch zoom, but it is kind of random. The on-screen feedback shows that my taps are being registered by the OS. I don't have a similar issue in Xournal++. Perhaps it has to do with my very high resolution 2560x1600 display?

Product name: PDF-XChange Editor Plus
Version: 10.4.0 (Build 388) (Sep 9 2024; 17:05:35) 64bit

Here's a video I took of the issue:
https://imgur.com/a/j4fdgYb

[Paul - PDF-XChange]

Hi all,

I am seeing on the Surface Pro - if I do as the OP said, rest my palm on the screen for 5 seconds, then try and use the pinch zoom it does fail at first , then becomes responsive on my second attempt to pinch zoom.

Interesting that it does need to be my palm, multiple fingers don't do it, and it is intermittent.

I couldn't get "The Edge" to do it.

[Paul - PDF-XChange]

Hi, guys,

apparently we are being lied to!!!

On investigation we learned that we are getting the wrong messages. From the investigating dev:

I reproduced and investigated this. A strange and inexplicable behavior of the system is there. Sometimes for ~1 second immediately after using the stylus, the system does not tell us that two fingers touching the screen, but tells about just one finger, which is not true... :

We will dig deeper. Thanks for bringing this to our attention.