[Qgis-community-team] compiling manual & image quality

[Jacolin Yves]

Le Friday 21 August 2009 13:34:09 Otto Dassau, vous avez écrit :
> On Fri, 21 Aug 2009 13:11:40 +0200
>
> MORREALE Jean Roc <jr.morreale at enoreth.net> wrote:
> > Otto Dassau a écrit :
> > > Hi Jean Roc,
> > >
> > > On Fri, 21 Aug 2009 11:04:10 +0200
> > >
> > > MORREALE Jean Roc <jr.morreale at enoreth.net> wrote:
> > >> Hi,
> > >>
> > >> I've been compiling the french manual for 1.0 (using texlive2008) but
> > >> the quality of the images is very low : the jpg figuring in the final
> > >> pdf are full of compression blocks making some captures hard to read.
> > >>
> > >> All the source's images have been localized and saved as png (96dpi)
> > >> so I would really like to have them show up in a better quality.
> > >>
> > >> What are the right options to change ?
> > >
> > > All images are simply converted during compilation without any change
> > > of size or
> > > resolution. In the english version, many figures are screenshots with
> > > only 72dpi
> > > resolution. You are right they sometimes could be better, but I don't
> > > know of
> > > any parameter for dvipdf or dvips conversion that make the images look
> > > better,
> > > except using images with a higher resolution - just my 2c.
> > >
> > > Regards,
> > >  Otto
> >
> > Hi Otto,
> >
> > It is not a matter of size or resolution but of jpeg artifacts due to a
> > drastic compression, when I compare the png/eps they do not show these
> > blocks but the jpgs included in the pdf are full of it. I think  the
> > quality setting used by convert is below 60%, if we could get it up to
> > 75% the images would be less blocky and still around 5% of the size of
> > the pngs
>
> Hi Jean Roc,
>
> ok, but since the pdf figures are created from eps format, I wonder where
> we can improve the process since b) uses eps files created in a):
>
> a) convert PNG and JPEG to EPS defined in the Makefiles
> b) create a PDF with dvipdf (a combination of dvips and ps2pdf) using EPS
> figures from a)
>
> and when I look at the branches/1.0.0/french/user_guide folder, I don't
> see any jpeg images except the qgis logo on the front page, or am I wrong?
>
> Can you give an example image where you think there is a big quality
> problem?
>
> Regards,
>  Otto

Hello,

I think the issue come from dvipdf ... I will try to looking for how to 
improve this, may be this week-end.

Y.
-- 
Yves Jacolin

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