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why is okular extremely slow when rendering PDF files?

toshiro
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I have a Core i5 machine running at 2500Mhz with 12 Mb of RAM, yet okular seems to render some PDF files like if it was running in a Pentium 1 computer. My computer is extremely fast in every task except when using okular (For the record, I've downloaded and use Acrobat Reader on the same files and they render them ok, not ultrafast but I don't have to wait for a page to render when moving quickly, in okular it takes a couple of seconds for rendering each page).

Is there anything I could do? (tweak some settings, etc).

Thanks in advance!
john_hudson
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Can you clarify the context? I've recently found that there seems to be a problem starting okular simply by clicking on a link but, if I right click and select it, it opens as fast as ever.


John Hudson, proud to be a member of KDE forums since 2008-Oct.
toshiro
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john_hudson wrote:Can you clarify the context? I've recently found that there seems to be a problem starting okular simply by clicking on a link but, if I right click and select it, it opens as fast as ever.


The opening method doesn't matter in my case, pdf files rendering is ultra slow with some pdf files, it's a pain to flip pages, I have to wait a couple of seconds to render each of them if I move quickly through the file ; the same files are rendered in a good speed in Acrobat for Linux.

I don't know if there is something I'm doing wrong (bad/missing configuration), if you have any advice, please let me know, I don't really want to use Acrobat :)

Thanks!,

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Toshiro
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john_hudson
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Some PDF creators seem to create very large files, particular if they contain particular types of images; Scribus is a particular culprit in this area. That always slows things but, without images, a 150 page PDF opens almost instantly and moving through it is similarly swift.


John Hudson, proud to be a member of KDE forums since 2008-Oct.
Geremia
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Yes, Okular is much slower than Acrobat Reader at rendering large, optimized PDFs, especially ones that are entirely images. Acrobat Reader and my Nook e-book reader render a page from a ~600 MB images-only PDF in less than a second, whereas Okular takes at least 8 seconds!
User avatar google01103
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Okular is but a gui front end to the Poppler library(s) that do the actual rendering and your question should be posted to them


OpenSuse 13.1 x64, KDE 4.12.x

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Geremia
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google01103 wrote:Okular is but a gui front end to the Poppler library(s) that do the actual rendering and your question should be posted to them
Thanks
Perhaps I'll try seeing if I have the recent Poppler first. thanks
Geremia
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google01103 wrote:Okular is but a gui front end to the Poppler library(s) that do the actual rendering and your question should be posted to them
Is it possible to make Okular use a different PDF rending library, such as MuPdf? thanks

Oh neat, I found this: okular-backend-mupdf
tosky
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Geremia wrote:
google01103 wrote:Okular is but a gui front end to the Poppler library(s) that do the actual rendering and your question should be posted to them
Thanks
Perhaps I'll try seeing if I have the recent Poppler first. thanks


If you install a newer version of Poppler, you should most probably also recompile the poppler backend.
Also, if you consistently find rendering issue like this, you'd better file a bug. Please note that Evince and Okular both use Poppler, but with different rendering methods; if you can test also with Evince you could provide some more details in the bugreport, but it could still be a Poppler issue.


tosky, proud to be a member of KDE forums since 2008-Oct.
Geremia
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How do I use a different backend in Okular other than Poppler? thanks
User avatar google01103
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Geremia wrote:How do I use a different backend in Okular other than Poppler? thanks


instead of Poppler you can use MuPDF but you will need the Olular/MuPDF plugin and you might need to find and compile the plugin


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tosky
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Geremia wrote:How do I use a different backend in Okular other than Poppler? thanks



Here is the source code: http://websvn.kde.org/trunk/playground/ ... lar/mupdf/, I think only few distributions provide it (playground, still not stable)
Please consider that:
- it's not as feature-complete as the Poppler one;
- if you could provide sample documents where poppler is slow, that could be really help developers.


tosky, proud to be a member of KDE forums since 2008-Oct.
Geremia
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tosky wrote:if you could provide sample documents where poppler is slow, that could be really help developers.
Any one of these PDFs loads very slowly with Poppler.
Geremia
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tosky wrote:Here is the source code: http://websvn.kde.org/trunk/playground/ ... lar/mupdf/, I think only few distributions provide it (playground, still not stable)
How do I download all those files at once so I can compile it? thanks
tosky wrote:Please consider that:
- it's not as feature-complete as the Poppler one;
Does it allow annotations, etc.?
tosky
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Geremia wrote:
tosky wrote:Here is the source code: http://websvn.kde.org/trunk/playground/ ... lar/mupdf/, I think only few distributions provide it (playground, still not stable)
How do I download all those files at once so I can compile it?
As any software hosted on the svn repository:
svn checkout svn://anonsvn.kde.org/home/kde/trunk/pl ... lar/mupdf/

I asked the developer and, given that mupdf does not provide a stable API for code (code quite in flux) it is possible that the backend could not compile. This is also the reason why that backend it's still in playground.

thanks
tosky wrote:Please consider that:
- it's not as feature-complete as the Poppler one;
Does it allow annotations, etc.?

It allows to create annotations as any other backend, but it stores them on a local file and it does not allow to save them back on the PDF. Also, it does not read the annotations stored in the file.


tosky, proud to be a member of KDE forums since 2008-Oct.

 
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