[texhax] Img quality in pdf

tomlobato tomlobato at ig.com.br
Fri Feb 4 18:36:09 CET 2005

On Fri, 4 Feb 2005 12:01:50 -0500, \"William F. Adams\" <wadams at atlis.com> 
> On Feb 4, 2005, at 11:24 AM, tomlobato wrote: 
> >   I \\usepackage{graphicx} for \\includegraphics{diagrama-vpn.jpg} in 
> >   my 
> > Latex/PDF document, but its generating lower quality images than the 
> > original. If you want to see diagrama-vpn.jpg and the PDF generated, 
> > 
> > see 
> > http://soc.if.usp.br/~tlobato/pdf. 
> > 
> >   For generate pdf, on Linux debian sarge, I use pdflatex version 
> > 
> > \"pdfeTeX (Web2C 7.4.5) 3.14159-1.10b-2.1 
> > kpathsea version 3.4.5\" 
> > 
> >   I already tried to convert image to EPS format and use epsfig 
> > package, and 
> > some anoother tricks, but all without results. 
> > 
> >   Some hint for enhance this image in the PDF? 
> Start with a better quality original. Presumably this was drawn up in 
> Visio or something along those lines, get the source program / 

GIMP 2.2. 
It has not svg support, but eps and pdf yes. 

> to cough up a vector .eps or .pdf or .svg or something. Worst case, 
> get them to make a 300dpi version (at least 4 times the pixels you 
> currently have left-right and top-bottom) 

in Gimp, I cannot see dpi conf when creating a new image, but I can set 
resolution, and the default is 72x72. How to obtain 300 dpi? Just setting 
300x300 in resolution? Well, as you can see, I need some more theory, where 
do I find a good doc for learn this? 

> The .jpg is 322 x 213 pixels/points (@ 72dpi) and when placed in the 
> .pdf is exactly the same. 
> The perceived difference in quality is that when viewed on-screen as a 
> .jpg it\'s displayed at 1 pixel in the image per one pixel on-screen. 
> When you place it in a .pdf, unless you view it at 100% on a display 
> coordinate system set to 72 dpi there\'s going to be scaling / 
> interpolation which results in a less than perfect representation. 

But when I see the final pdf document at 100%, I can see some differences in 
two images: Look the blue lines linking the computers and and the borders of 
the light blue rectangles in http://soc.if.usp.br/~tlobato/pdf, in the pdf, 
it is zigzag, and in the orginal jpg, not. 

> William 
> -- 
> William Adams, publishing specialist 
> voice - 717-731-6707 | Fax - 717-731-6708 
> www.atlis.com 

Thank you very much!! 

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