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Posted By: alternaut PDF display woes - 09/12/15 07:23 PM
While trying to peruse an antivirus utility coverage report from Security Spread, I was struck by the problems that caused in both Safari and Adobe Reader/Preview*. These reports are relatively small (~1.7MB) spreadsheet-based PDF files of a kind that I rarely encounter. They load rather slowly and SPOD profusely when scrolling.

Trying to load one initially crashed Adobe Reader, and it won’t display (= blank Reader window) on subsequent attempts, until I select Select All. It then displays the entire width of the document in the Reader window at a magnification that renders it unreadable. But when I try to enlarge it or scroll down, it vanishes again with a SPOD interlude. Both Safari and Preview open it, albeit slowly too. Scrolling and/or enlarging once again triggers a prolonged SPOD show in either app, but at least I can eventually view the contents.

I wonder whether this is due to a property of the file (my guess), or to an (configuration?) issue with my Mac. In other words: can I improve things? Any and all comments are welcome. tongue


*) iMac Retina late 2014, 4GHz i7, 16GB RAM, AMD Radeon R9 M295X 4GB, 3GB Fusion drive, Mac OS X 10.10.5, Safari 8.0.8, Preview 8.0, Adobe Acrobat Reader DC 15.8.20082.147029
Posted By: artie505 Re: PDF display woes - 09/12/15 10:12 PM
OS X 10.6.8/Safari 5.1.10/Preview 5.0.1, and I'm experiencing similar problems. (I see this in Safari... this in Preview, both accompanied by slowdowns and beachballs.)

Aside: The latest d/l is almost a year old; is it worth the effort?

Edit: I've accessed these reports in the past, and I think they rendered similarly in Safari, with d/l's OK in Preview.
Posted By: joemikeb Re: PDF display woes - 09/13/15 12:51 AM
FWIW Those files open correctly and almost instantaneously in El Capitan —Preview 8.1 (877) — but I had to zoom in at least 7 or 8 times before the text was large enough to read.
Posted By: artie505 Re: PDF display woes - 09/13/15 04:36 AM
Oops...forgot to try zooming, which gives me a readable, but really slowly reacting, doc in Preview (@ 12 x command-+).
Posted By: alternaut Re: PDF display woes - 09/13/15 05:08 PM
Thanks for the responses. This morning, after having shut down/restarted, things seemed a bit better, but were still far from satisfying. Stating that things are slow doesn’t quite cut it, so I provided some numbers below. That’s mostly to give you an idea of what I’m seeing rather than to be perfectly accurate. Still, although variable, the numbers tend to be close to what I list, as are the patterns in which they occur.

To begin with, loading the file in Safari* fairly consistently takes about 22 sec.
- Zooming (via the zoom button, or with Command+) was instantaneous, but 3-6 sec later the SPOD appeared for 15-20 sec. Clicking anywhere in the window, resizing or repositioning it invariably brought back the SPOD for another 15-20 sec. Sometimes that even happened without doing anything at all with mouse or keyboard.
- Scrolling was abnormal, in the sense that clicking in the scroll bar invariably returned the view to the top (Vert) or the left (Hor), regardless of where in the respective scroll bar I clicked. This was accompanied by at least 10-15 sec of SPODding. If the scroll handles were already at the top or the left, clicking had no effect other than bringing about the SPOD. Dragging the scroll handle worked, but only for a short distance (about half a page worth max), after which dragging was non responsive for about 5 sec.
- The cursor itself behaved abnormally too, often remaining in Insertion bar mode where it should return to arrow or vv.

Preview fared little better, with foibles all its own. The file loads in about 5 sec, but
- SPODs for over 30 sec after hitting the zoom button once. Moving the cursor just a tad brings on another bout of on-off SPODding that may last up to 3 minutes (!). Reducing the window size from max to about half took another 25 sec. The next zoom click took altogether 1 minute before the on-off SPODding stopped. Usually though, clicking on the zoom button produces an instantaneous result, followed after 3 sec by up to 40 sec SPODding, briefly interrupted at 15 and 30-35 sec. Go figure.
- Scrolling was an unadulterated pain too: just clicking the scroll handle often (but not always!) brings up a 15-20 sec SPOD. Dragging it brings another, slightly shorter one, before the window scrolls a few lines. Clicking in the scroll bar works as expected (e.g., one ‘page’ up/down or left/right), but only after 5-10 secs being unresponsive, followed by another 5-30 sec SPOD. And then there is the odd case where there is no delay at all…

All this rarely seems to touch CPU cycle or RAM use, and then only marginally.

Just for giggles, I loaded the file in about 2 sec into Preview 5.0.3 under Snow Leopard (10.6.8) on a 2008 MBP. After a subsequent SPOD of about 25 sec, it zoomed fairly snappily and scrolled at about one line or page per sec. In contrast, Adobe Reader 11.0.11 only showed an empty window. On the iMac under Yosemite, AR DC 15 ‘improved’ upon that by displaying placeholder graphics at all zoom levels. This strongly suggests that there is something non-standard about these files, but even so, to say that I am underwhelmed by the way the then top of the line 2014 iMac handles them doesn’t quite cover my feelings…

*) I turned off extensions and Little Snitch to minimize any delays these might cause.
Posted By: dkmarsh Re: PDF display woes - 09/13/15 08:03 PM

Quote:
All this rarely seems to touch CPU cycle or RAM use, and then only marginally.

FWIW, although my Late 2012 mini running Yosemite and Safari 8 performs very similarly to what you describe, the beachballing is consistenly accompanied by processor use of 100% and over. My installed RAM is just 4 GB, though, so perhaps that accounts for the difference in some way...
Posted By: joemikeb Re: PDF display woes - 09/13/15 09:03 PM
I looked at those files again using the El Capitan Gold Master running on a Late 2012 Mac mini with 16GB RAM and observed none of the problems you experienced. I could scroll freely from the top to bottom and left to right margins and without a SPOD using Preview 8.1.

However — there is definitely something funky in the PDF construction of the file. When I opened it with PdfPenPro 7.3. PdfPenPro was slower than Preview 8.1 opening the file and I did get a couple of brief SPODs while scrolling around the document, but there is a second pane on the left side of the widow containing what appears to be a duplicate copy of the document. I cannot determine if it is a duplicate or not as it is displayed too small to read and I was unable to zoom in on it. Weird stuff! confused

I opened the document in Adobe Acrobat X and it started out with a black screen and then turned blank white. The scroll bars indicate it is scrolling up and down, but nothing the display remains blank white.

I do not believe the problem is with your iMac, Yosemite, Preview, or Adobe Reader rather it is something in the structure of the document itself. I would be tempted to speculate that it is a result of one of Adobe's proprietary PDF features that has not yet been released into open source but I downloaded Adobe Acrobat Reader DC and like the much older Acrobat Pro X it just came up with a blank window. Frankly at this point, I am amazed that Preview 8.1 can handle the document. Some Apple developer(s) deserve(s) kudos for that.
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