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

[Otto Dassau]

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