Why is PDF scrolling in Preview choppy but smooth in Safari?

Discussion in 'Mac Basics and Help' started by Yeti89, May 7, 2013.

  1. macrumors member

    Joined:
    Dec 27, 2011
    #1
    I have been frustrated with this ever since I bought my 15" rMBP last year. I am a product design student and when I view my PDFs in Preview it is extremely choppy. I understand that they are vector graphics and so they are being rendered on the fly. But, Safari seems to handle them okay. Is there a reason Apple hasn't applied the same scrolling engine from Safari to Preview. I know I am probably dumbing this down but I feel like it would be as simple as a cut and past code job.

    Any thoughts?
    Also, is there anything an average consumer like me can do to get Apples attention and have them fix this?
     
  2. macrumors 68020

    Joined:
    Jun 15, 2012
    #2
    Preview and Safari both use exactly the same PDF rendering engine, so if there are differences between the same file, then something else is going on.
    This may simply be "a problem you are having on your computer" rather than "an issue that Apple needs to fix".

    If the file is very large, then you may see some choppiness as a new bit is loaded in from the disk. However, that should be the same on both apps.

    Have you tried different viewing styles in Preview? e.g. Continuous, Single Pages, with/without thumbnails, etc?

    As a test, create a brand new user account and test the problem there. If the scrolling is improved, then you know that the cause is in your original account. Go back to that account and try emptying caches, using a utility like Onyx, or even delete the Preview preference file. (Access the Go menu in the Finder with the <alt> key held down, select Library, and navigate to the Preferences subfolder. Delete the com.apple.preview.plist file.
     
  3. thread starter macrumors member

    Joined:
    Dec 27, 2011
    #3


    Thanks for your reply. I have done all this and more. What it has boiled down to is I can reproduce this on every rMBP model I have come across including in store models. I have done it multiple times with Apple Genesis but know one can provide an explanation.
     
  4. macrumors 68020

    Joined:
    Jun 15, 2012
    #4
    Is it all vector PDFs, or some specific ones?

    Do you have a link to a file that shows the issue?
     
  5. thread starter macrumors member

    Joined:
    Dec 27, 2011
    #5

    Its all vector PDFs. The more content the harder time Preview has. But like I said safari is fine.

    Here is a link to a file.
    https://www.dropbox.com/s/17voali6rs2pm36/Skinner.pdf
    Download it and then open it in safari and preview and you'll see the difference. Don't just view it in the Dropbox link.
     
  6. macrumors 68020

    Joined:
    Jun 15, 2012
    #6
    That file surely contains bitmaps; it's not completely vector....?

    There is some slight judder in Preview.

    However, I have much larger bitmap (and vector) PDFs that don't show any of the same judder in Preview or Safari.

    I can't say why there's a difference between the two apps, or why that particular PDF causes it. Acrobat preflight suggests some issues with transparency, though.
     
  7. macrumors 6502a

    Joined:
    Apr 4, 2013
    Location:
    in a ziplock bag inside a car's trunk
    #7
    I have the exact problem but the other way around: PDFs in preview are great scrolling and smooth and what not. But if a PDF is opened in safari...
     
  8. thread starter macrumors member

    Joined:
    Dec 27, 2011
    #8

    I don't know to much about this stuff but you are right it isn't an all vector file. What I meant is that with all my vector/bitmap PDFs have the issue. Also, the more complicated the file the bigger the stutter.

    I notice less of a jitter on my new iMac but my guess is because it is pushing less pixels. Also, while scrolling my preview CPU usage jumps to around 95% but when I scroll in Safari the cpu usage is around 15-20%.
     
  9. macrumors 6502a

    Joined:
    Apr 4, 2013
    Location:
    in a ziplock bag inside a car's trunk
    #9
    replying, because i managed to solve this (with a web search):

    first i went to applications' folder, where i deleted adobe pdf viewer.
    then i went to library -> internet plugins -> deleted the 2 adobe pdf plugins that were there -> restart safari.

    now everything is smooth :)
     
  10. thread starter macrumors member

    Joined:
    Dec 27, 2011
    #10
    So this fixed choppy scrolling in preview? My Safari is already working well
     
  11. macrumors 6502a

    Joined:
    Apr 4, 2013
    Location:
    in a ziplock bag inside a car's trunk
    #11
    you are right, but as my problem was like yours (whilst the other way around) i figured that if someone would do a search, it'd be good to post a solution.
    anyway, you can try what i did. maybe it will help
     
  12. macrumors 6502

    sshhoott

    Joined:
    Feb 6, 2010
    #12
    I was wondering the answer to this question when Mountain Lion came out as well. I have used almost all the Macs in Apple Store and they demonstrate smoother scrolling in Safari as compared to Preview, no matter what you're viewing.

    As you mentioned, Preview uses more CPU but Safari doesn't. I think Safari is using a GPU Hardware accelerated engine for scrolling. It could also be that the Webkit2 engine that Safari uses is allowing smoother scrolling.

    Apple's website: http://www.apple.com/ca/osx/whats-new/features.html#safari
    Highlights smooth scrolling as one of the main features of the Safari browser:

    "Smooth scrolling
    Thanks to hardware acceleration, web pages scroll smoothly in the browser window even when your Mac is loading new web page content."​

    Also have you tried forcefully using only the Dedicated GPU instead of the integrated one? Does it make a difference?

    I think not even OS X 10.8.4 update will address this issue, but it really is a enhancement feature, rather than a bug. OS X 10.9 will probably include smooth scrolling throughout the OS, including Preview (if Apple truly cares about their customers' needs and wants). Think about it: if iPhone and iPad can have smooth scrolling throughout iOS, why can't OS X?
     

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