Zoom In/Out Display Rendering Delay When Using Pinch Gesture on Touch Screen

[Jerry9]

SYSTEM
PDF-XChange
Version 7 Build 327
Windows 8.1
Asus T100 10" Laptop with touch screen.

BACKGROUND
Preferences > Accessibility Options > Override Document Colors
> Changed Background Color to gray and Text Color to green.

PROBLEM
When I use the touch screen "pinch" gesture to zoom in and out, there is a noticable (1/4 to 1/2 second) delay between the time of the pinch and the rendering of text and images on the display.

NOTE: The Foxit PDF Editor (v9.3) does NOT have this problem when tested on the same laptop.

When I unchecked "Override Document Colors", the pinch gesture now shows green text (with a 1/4 second delay) before changing to black, as if it hasn't quite forgotten the previous setting.

[Tracker Supp-Stefan]

Hello Jerry,

Yes - when you zoom in/out of a page - we will store the various renditions - ready for reuse next time you get back to the same zoom level - so that's why you see a "flash" of the old render before it gets re-rendered again. Can you please check Under File -> Preferences (Ctrl+K) -> Page Display -> Rendering whether Synchronous Page Rendering is turned on or off?

Regards,
Stefan

[Jerry9]

Synchronous Page Rendering has not been altered since I installed the software. It is set to the default, which is "Auto".

[TrackerSupp-Daniel]

Hello Jerry9,

Can you please try changing synchronous page rendering to on and off each, and then let us know if the handling improves for either?
Also if you could, please open the Performance category of the preferences, and send us a screenshot of what you currently see in that window.

Thank you!

[Jerry9]

I already tried that. There is no change in behavior. It seems there is a big delay in rendering images, but text is also delayed.

I tried several things including setting pixels to 72 per inch, down from 300. There was no change in the problem.

I tried unchecking the restore zoom settings when opening from Recent list. No change.

QUESTION
Are you able to replicate the issue on your system?

[TrackerSupp-Daniel]

Hello Jerry9,

Thank you for verifying that. So far I have been unable to replicate the issue, which is why we are still going through the troubleshooting steps. Does this happen with every document, or only select documents? If only select documents are affected, please send us one of those for testing.

As an aside, do you see the same behavior when using Ctrl+Scroll on the document, or does this only appear when using a pinch?

[Jerry9]

The file attached is only a portion of a book of over 1,000 pages.
The problem seems to happen with every document.

I don't have a mouse. But pinching the touch pad gives the same results as pinching the screen.

Page Display Options (These are my settings)
Initial Display
Restore: checked
Default View: auto
Restore ... Recent lists: Unchecked
Continuous ; Automatic
Respect document settings: checked
Display large images: checked
Resolution: 96

[TrackerSupp-Daniel]

Hello Jerry,
We have managed to reproduce the issue and are now taking a look at possible resolutions for you.
For the time being, I apologize for the inconvenience.
Have a nice day!

[Jerry9]

Being able to reproduce the issue is a good first step. It also means it's not just a problem with my system. I'll await your updated reply.

[TrackerSupp-Daniel]

Hello Jerry,

We are still working on this, but a slight modification has made it into build 327.1. It does not improve the delay much, but it is a somewhat noticable difference. I do not have any timeline for the final push on this, but i hope that this is enough to tie you over until it is fully resolved.

[Jerry9]

There seems to be some improvement. Kudos (Thumbs up) for addressing this so quickly. With that kind of dedication to improvement, PDF-Xpress is the best alternative to Adobe Acrobat Professional I have found, even better than Foxit (although foxit doesn't have this zoom problem).

[Tracker Supp-Stefan]

[MedBooster]

I'm confused,
some screenshot instructions on where to enable the pinch to zoom gesture would help greatly.

edit: it seems we are talking about regular zooming, as opposed to zooming into a specific region of the window: https://forum.pdf-xchange.com/viewtopic.php?t=41020

[TrackerSupp-Daniel]

Hello, MedBooster

There is no option to enable this to my knowledge, it is always active. Simply place two fingers on the screen and pinch or separate to begin zooming as you do in any other app. As mentioned in the other topic you linked, this does only work within the opened PDF document and not in the UI. I have also recently noticed that on some highler resolution displays with scaling enabled, the "location" where the pinch is registered is incorrect (EG on a monitor at 200% zoom, the pinch location is in the relative unscaled location on the screen, IE: in the top right quarter of the document) I will be passing that on the to dev team for review.

Kind regards,

[MedBooster]

Hello, MedBooster

There is no option to enable this to my knowledge, it is always active. Simply place two fingers on the screen and pinch or separate to begin zooming as you do in any other app. As mentioned in the other topic you linked, this does only work within the opened PDF document and not in the UI. I have also recently noticed that on some highler resolution displays with scaling enabled, the "location" where the pinch is registered is incorrect (EG on a monitor at 200% zoom, the pinch location is in the relative unscaled location on the screen, IE: in the top right quarter of the document) I will be passing that on the to dev team for review.

Kind regards,

ah ok. To prevent accidental touches on touch screens with stylus support (that don't have palm rejection) you could consider enabling having to use two fingers to move around. Maybe another idea would be to be able to enable or disable zoom lock (from the regular pinch gesture – not the regional one I was suggesting in another post) – basically not allowing you to zoom in or out with touch pinching, until you press the button again and unlock it.

[TrackerSupp-Daniel]

Hello, MedBooster

We are instead going to be looking at ensuring that single finger scrolling has an option which can prevent accidental selection of content (in particular comments). I cannot say when that will be coming, but it is in on the list.

Kind regards,