[Scribus] Slow Rendering PDF exported from scribus

PLinnell mrdocs
Thu Jul 7 23:24:01 CEST 2005


On Thursday 07 July 2005 19:03, Craig Ringer wrote:
> On Fri, Jul 08, 2005 at 12:48:21AM +0800, Craig Ringer wrote:
> > OK. That makes sense then. It sounds like they were possibly
> > linearized either on output, or by Acrobat later. This is
> > sometimes called "optimize for web view".
>
> Five minutes on Google would've told me that won't help. Sorry.

"Linearizing" is the process of making the internals of a PDF linear 
and allow apache (mostly) to do special tricks to allow PDF to 
download and display in Reader page by page. 

This makes the PDF usable faster, at some cost to file size.

Ghostscript can also linearize a PDF too. 

man pdfopt give the options
>
> > On a side-note, I'm astonished to hear of some of the rendering
> > times reported here. For example, I've always found Acrobat
> > Reader 6 / 7 on Mac OS X just fine with rendering times. Acrobat
> > 4 / 5 under Mac OS 9 is another matter ...  so slow it hurts.
>
> I was only able to see what everybody's taking about by firing up
> Acrobat Reader on my 150MHz laptop. That said, I see what you mean.
> The two key features are:
>
>   - Text is rendered in small chunks, each of which takes a little
> while to draw.
>   - Rendering is highly out-of-order
>
> I don't know enough about PDF to explain the first point, but I
> *have* seen it before, and from Quark+Acrobat documents at that.
> Maybe Franz or Peter will have some thoughts on that. If I had to
> make a wild guess it'd be that we're breaking up text into small
> stretches to get the desired positioning (workarounds for older /
> buggier PDF viewers and RIPs, IIRC). Maybe to improve print
> reliability?
>
> Personally, I'm wondering if Acrobat has some optimizations for
> text done certain ways, and the Scribus text is forcing it to fall
> back on its default slow-but-comprehensive rendering.

It is very important to understand PDF internally is "non-linear".

The way objects inside a PDF are packed for minimizing size, not human 
readablilty.

My testing with of that file with a handful of different versions of 
Acrobat Professional, Acrobat Reader on both Windows 2k,Win98 and 
Linux did not seem excessive. This is on some relatively modest 
equipment. (PIII 933, with 256 Mb Ram on Win2kSP4)

Rendering of some Scribus PDFs are probably a bit slower than other 
apps. This certainly can be improved, but IMNSHO, a very small price 
to pay knowing with modern print gear 99% of the time Scribus gets it 
right and has been doing so since 0.9.x days.

Peter





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