* Image compression/resizing in PDFs
@ 2011-10-21 9:54 John Devereux
2011-10-21 13:20 ` Peter Münster
2011-10-24 13:46 ` Hans Hagen
0 siblings, 2 replies; 5+ messages in thread
From: John Devereux @ 2011-10-21 9:54 UTC (permalink / raw)
To: ntg-context
Hi all,
Is there a way to have context automatically compress or resample
included images to a given output resolution? I have not been following
recent developments...
I can obviously "pre-reduce" all images to the desired dpi. But:
1) This is a bit of work (and hard to get non-technical people to do)
2) In 5 years time we might want the images to be higher resolution and
not be as concerned about PDF size. But the information will be lost (or
be elsewhere).
So a command line or document setting would be ideal, is there such a
thing? \setpdfimageresolution[300dpi].
Thanks,
--
John Devereux
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* Re: Image compression/resizing in PDFs
2011-10-21 9:54 Image compression/resizing in PDFs John Devereux
@ 2011-10-21 13:20 ` Peter Münster
2011-10-24 13:46 ` Hans Hagen
1 sibling, 0 replies; 5+ messages in thread
From: Peter Münster @ 2011-10-21 13:20 UTC (permalink / raw)
To: mailing list for ConTeXt users
On Fri, Oct 21 2011, John Devereux wrote:
> Is there a way to have context automatically compress or resample
> included images to a given output resolution?
Hello,
See also
http://archive.contextgarden.net/thread/20110629.173015.6dcd7b3e.en.html
t-degrade.tex is broken with latest context. If you fix it (should be
easy), please send me the patch! :-)
(Sorry, too busy now for fixing it myself...)
--
Peter
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* Re: Image compression/resizing in PDFs
2011-10-21 9:54 Image compression/resizing in PDFs John Devereux
2011-10-21 13:20 ` Peter Münster
@ 2011-10-24 13:46 ` Hans Hagen
2011-10-24 14:29 ` Aditya Mahajan
1 sibling, 1 reply; 5+ messages in thread
From: Hans Hagen @ 2011-10-24 13:46 UTC (permalink / raw)
To: mailing list for ConTeXt users; +Cc: John Devereux
On 21-10-2011 11:54, John Devereux wrote:
>
> Hi all,
>
> Is there a way to have context automatically compress or resample
> included images to a given output resolution? I have not been following
> recent developments...
>
> I can obviously "pre-reduce" all images to the desired dpi. But:
>
> 1) This is a bit of work (and hard to get non-technical people to do)
>
> 2) In 5 years time we might want the images to be higher resolution and
> not be as concerned about PDF size. But the information will be lost (or
> be elsewhere).
>
> So a command line or document setting would be ideal, is there such a
> thing? \setpdfimageresolution[300dpi].
You can plug in a converter:
\startluacode
figures.converters["png"] = {
["lowres.png"] = function(oldname,newname,resolution)
os.execute(string.format('gm convert -depth 1 "%s"
"%s"',oldname,newname))
end,
}
-- the following is automatic in next beta
figures.suffixes["lowres.png"] = figures.suffixes.png
\stopluacode
And then use:
\starttext
\externalfigure[mill.png][conversion=lowres.png]
\stoptext
downsamples images are cached so the overhead is minimal
Hans
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Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
| www.pragma-pod.nl
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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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archive : http://foundry.supelec.fr/projects/contextrev/
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Image compression/resizing in PDFs
2011-10-24 13:46 ` Hans Hagen
@ 2011-10-24 14:29 ` Aditya Mahajan
2011-10-24 14:49 ` Hans Hagen
0 siblings, 1 reply; 5+ messages in thread
From: Aditya Mahajan @ 2011-10-24 14:29 UTC (permalink / raw)
To: mailing list for ConTeXt users
> downsamples images are cached so the overhead is minimal
Is caching based only on the figure name? If I change the original figure,
will the cached figure be updated?
Aditya
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___________________________________________________________________________________
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* Re: Image compression/resizing in PDFs
2011-10-24 14:29 ` Aditya Mahajan
@ 2011-10-24 14:49 ` Hans Hagen
0 siblings, 0 replies; 5+ messages in thread
From: Hans Hagen @ 2011-10-24 14:49 UTC (permalink / raw)
To: mailing list for ConTeXt users
On 24-10-2011 16:29, Aditya Mahajan wrote:
>> downsamples images are cached so the overhead is minimal
>
> Is caching based only on the figure name? If I change the original
> figure, will the cached figure be updated?
Sure,
local oldtime =
lfs.attributes(oldname,'modification') or 0
local newtime =
lfs.attributes(newname,'modification') or 0
if newtime == 0 or oldtime > newtime then
In fact it's just integration of old resource library code (ruby stuff
that happened between runs).
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
| www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://tex.aanhet.net
archive : http://foundry.supelec.fr/projects/contextrev/
wiki : http://contextgarden.net
___________________________________________________________________________________
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2011-10-21 9:54 Image compression/resizing in PDFs John Devereux
2011-10-21 13:20 ` Peter Münster
2011-10-24 13:46 ` Hans Hagen
2011-10-24 14:29 ` Aditya Mahajan
2011-10-24 14:49 ` Hans Hagen
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