box.com PDF preview display errors

[bbennett2]

A math teacher I work with is having some trouble with PDF uploads displaying gibberish.

I don't think it's a PDF encoding issue because it opens fine locally and if she shares it as a Google upload. But, when it's uploaded to Canvas, the box.com-powered preview replaces all of the coefficients with "0" or "1". Here's a screenshot of the PDF in Canvas:

...and a screenshot of the same PDF opened in Google Drive:

Has anyone else seen this issue? I'm assuming it has something to do with the way box.com is interpreting the PDF and not the document itself.

My recommendation, currently for the teacher, is to post these documents as a content page as links back to Drive. But, that's really a hassle because she then has to manage two different outlets. Any ideas?

[ebissoon]

Hi Brian,

This may not help you except to say that you're not alone. I experienced a similar issue with excel spreadsheets in BOX a while back (Odd orientation for Excel files when viewed using BOX). My final solution was to embed the file using Google drive/docs. It wasn't perfect (and it was ultimately rejected by the user for being a bit too complex) but I did achieve some success with it. I'm not certain how this will work with a pdf file embedded in Canvas/Google but it's worth a try maybe?

Thanks

Eric

[bbennett2 · Accepted solution]

I figured I wasn't alone...thanks for the confirmation, though. It's definitely strange that the document can't be displayed correctly through a web-based repository.

I had another brainstorm that I suggested to the teacher. She can upload the files into a Drive folder. A spreadsheet using a script can then keep a log of all the files and their URLs, one in each row. The teacher only needs to embed the single spreadsheet rather than edit a Content Page each time she adds a file. It's still not a great solution, but it's better than all of the editing that would need to happen otherwise.

[don_bryn]

I don't know if this is helpful or not, but I've had similar issues with pdfs when displaying music (This was not in Canvas).   It ended up the issue was with fonts because the music font had to be embedded into the pdf. The image above looks to me like the pdf viewer is displaying the page with either a different font or at least font settings.   If you look closely you'll see that all the characters are in the correct places, but are larger than the original and therefore overlap each other.  Your teacher could see if there is a setting to embed specific fonts when creating the pdfs.  Or possibly try creating the pdf with different software to see if that's the issue.

[bbennett2]

I had forgotten about embedding fonts, so thanks for the reminder.

I made a test document with some equations created in Word and the font embedded and I'm still seeing some markup errors when the PDF is uploaded to Canvas. It displays fine on my computer and with Google Drive, so I'm still convinced it's some issue on box.com's end when they encode/decode the document.

[kmatson]

Different error in box preview of PDF files. The in-line preview and the preview in files are not displaying the entire pdf file so students that are counting on that display to be complete are missing content.

Faculty are creating their pdf files in multiple ways but unless they enhance their scan in Adobe their students may not be seeing everything they saw in class if they view in the Files viewer or the in-line preview rather than downloading the file and viewing in Adobe which of course defeats the whole purpose of the preview.

Math writes up extensive notes and takes to a scanner and this is the result. The file preview many students use doesn't show the entire pdf file. The one on the left is the Canvas preview and the one on the right is the complete view from Adobe Reader.

We can fix the pdf files by using Enhance your scan in Adobe but why is this happening, how do we know when we have to enhance the scan? I don't know enough about pdf files to know what or how to anticipate when it will drop content. Does anyone else know?

Thank you,

Karen Matson

University of Oregon