XOD Documents Sometimes Appear Blurry

[David Compton]

We have a customer reporting that for some users on iPads the XOD documents appear "blurry" when loaded.  In some instances the document "sharpens up" after a period of time - from a few seconds to a minute or so.  In other instances the document never sharpens up.  The app is an Ionic app using the latest version of the web viewer.  The documents are being loaded using range requests.  This problem does not  seem to occur on other platforms.  Do you have any thoughts as to why this would be happening?  Is there a setting we can tweak that would help?

Thanks,

David

[Matt Parizeau]

Hi David,

WebViewer first loads a lower res thumbnail and then when the page is finished rendering the high res canvas is placed over top. This is what's happening when the document is blurry and then sharpens up. If it takes a long time for the document to sharpen up that may mean the document is complicated and it takes quite a while to render. Taking a minute to render seems like an unusually long time though.

Does this only happen on newer iPad pro devices? These devices have a devicePixelRatio of 3 (most iOS devices have a value of 2) which means WebViewer will render the page with a width and height 3 times larger each, so 9 times larger in area, and then scale it down so that it maintains quality on the high res screen.

What you could try is adding the following to your config file which will cap the rendering multiplier to 2 which should avoid excessive memory usage and rendering time:

if (window.utils.getCanvasMultiplier() > 2) {

    window.utils.setCanvasMultiplier(2);

}

If this doesn't help would you be able to send us any of these XOD files so we could profile the performance on our end?

Matt Parizeau

Software Developer

PDFTron Systems Inc.

[David Compton]

Thanks Matt appreciate your response.  I will try making the change to the config file and see if that resolves the issue.  Unfortunately the problem is inconsistent in that some documents work OK for some users but not for other users.  As far as I know they are all using iPad Pros.  However I have asked the customer to confirm if this is the case.  In one example they gave me the blurriness never cleared up at all - but only on one device - on other devices it did clear up.

--
You received this message because you are subscribed to the Google Groups "PDFTron WebViewer" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pdfnet-webviewer+unsubscribe@googlegroups.com.
To post to this group, send email to pdfnet-webviewer@googlegroups.com.
Visit this group at https://groups.google.com/group/pdfnet-webviewer.
For more options, visit https://groups.google.com/d/optout.

[mi...@stellarlibrary.com]

Thanks Matt, 

We had not progressed on this since: https://groups.google.com/forum/?utm_source=digest&utm_medium=email#!searchin/pdfnet-webviewer/stuck$20preview%7Csort:relevance/pdfnet-webviewer/vIgA1-8o0mw/YoGGbsg_EAAJ

Will take stab at that for our next release.

Mike