PDF XChange Forum

Hello,

First off, thank you for this software. It is probably the best pdf software available right now for high-dpi devices.

However, I do find a few issues. Using inertial scrolling during touch input is finicky: Sometimes the inertia will activate for a flick, and sometimes it won't. If there was an option to tweak inertia to make it feel a lot like touch scrolling during chrome, that would be great.

Also, when you do scroll using the trackpad or the touchscreen, the border between each page sort of... fades out. I'm not sure if this is a known bug, but I am using a 3200x1800 resolution screen with windows precision drivers on trackpad.

Also, I'm noticing a lot of screen tearing for image-heavy pdfs. I'm guessing this has to do with the high resolution, but is there any way to fix this?

Also, FYI: There is an FAQ question about increasing scrolling speed in-app. I was actually able to change the scrolling speed by changing Preferences-->page display options--> "Use resolution: _______ pixels per inch." higher ppi would result in faster scrolling.

Hello litepegasus,

Regarding inertia activating from a flick, do note that this only works on base content items when using the hand tool, as comments, and links the hand tool is able to interact with, so if your "flick" happens to begin on one of them, it instead registers as you clicking on the item, then if you release your finger while above the same item, it will activate it, either following the link, or selecting the content item. This works the same even with the regular mouse controls, and acts as a "whoops I didn't want to click that" prevention, so that if you accidentally click on something, and realize before you let go, you can move the mouse or your finger away before releasing to avoid performing the action.
As such, this is intended, areas like the "ToC" of a document, which are packed with links, often need to be scrolled by using either the page edges, or two finger scrolling, which will ignore links and most content.

I am unsure what you mean by the page borders sort of fade out. Are you meaning it looks like they blend together when you are scrolling very fast?
With screen tearing of high resolution image heavy documents, You may be able to mitigate it by enabling "synchronous page rendering" under Prefrences (Ctrl+K) > Page display > rendering. Can you try that and let us know if it improves? If not, please try to take a video of the screen tearing happeneing, and share it with us here (you will need to zip the file to put it on the forums).

Regarding the FAQ, you are speaking of this article, yes? In which case, there is already a section at the bottom that certainly does explain you can do that.

Kind regards,

Hello Daniel,

Thank you for your response. First off, I didn't even see that changing the DPI changed the scrolling speed at the bottom, so that is my fault, and I apologise. Maybe move that section to the top of the article? people who search for "how to increase scroll speed in application" are usually looking for that answer.

The touch-intertia scrolling issue that I see is when using any pdf at all, even those without links or comments. I don't have this issue when using other PDF apps like SumatraPDF or Adobe.

I turned on synchronous page rendering, and I see no change. I've attached a video to this response.

Hello litepegasus,

That is a good point, I will modify the article shortly to switch the positions of those passages, thank you for the suggestion.

With our test device, I was not able to reproduce the inertia scrolling issues you have described, might I ask for the Make and Model of your devices so we can investigate them more closely?

Regarding the "page break blending" and "screen tearing" issues described, the Dev team is now aware of these, however for the moment these are low priority items, as they do not negatively impact the functionality of the application and only present a minor quirk in the visuals when scrolling at extreme speeds.

Kind regards,

I am using a dell xps 13, QHD, i7-6560u. I suspect it may be an issue with specifically High-DPI displays, which may be why you cannot replicate the issue on your test device.

And it's good to know that the dev team now knows about the issue. Once again, I think this is something that is specific to high-DPI devices, and I'm not sure if you'll be able to emulate it on your test device.

Hello Litepegasus,

I was testing with our MS Surface, which has a 2736x1824 display, so it is certainly in the high DPI spectrum for a 12.5" display. that said, the branding could have an effect here, Our touch capabilities tend to work with windows directly best, but in some cases can conflict with other manufacturers drivers.

I have attached a registry key which will disable the Editor's build in touch support, this will force it to use the system's native touch handler instead, and should eliminate the possibility of such conflicts causing issues like the flick issue you are seeing. Please close the Editor, then unzip and run the attached key then restart the Editor and let us know if those issues are resolved.

For security sake, you can also find the plain text of this registry key here: Kind regards,

I applied the registry edit, restarted, and nothing has changed. I then went into the registry to see if the setting has been applied, and it appears to have. It still feels the same.

Hello Again Litepegasus,

I apologize for the long delay in getting back to you. We have done some more extensive testing and managed to reproduce the issue on a few devices. We should be able to resolve it in the future, but will not be able to in time for the upcoming 332 build release.

Kind regards,

That's fine. I'm glad to know that there is a fix incoming.