[NTG-context] shrink JPGs to some resolution (dpi) ?

Harald Koenig koenig at tat.physik.uni-tuebingen.de
Tue Mar 10 00:33:48 CET 2015

On Mar 09, Aditya Mahajan wrote:

> Why not eliminate the orignal high quality jpegs altogether? Use

one reason is that the jpgs are not in final shape either.
the selected pictures will be reworked from raw files, 
maybe some brightness/contrast correction, clipped,  etc.

whenever the images are reworked, this will happen on the original pictures
and then the resize/... steps are needed again.

yes I know, makefiles and easy shell scripting  can do all this work (actually they do already;)
but I dream of reducing the number of tools, processing steps, ...

I thought everyone using jpeg images might have the same interest without additional hassle: 
just make my output PDF suitable for printing at 300dpi quality or similar...
runtime potimisation (e.g. caching) is a different topic,
and that also can be solves nicely with lua I'd guess?!;-)

> imagemagick or your favorite photo batch processor to convert all
> the high quality jpegs to low quality jpegs.

ACK -- sort of:  
have a look for my next mail "jpeg problem: Dimension too large"
as I'm running into a strange problem exactly using imagemagick to shrink the images...

and I need information about the rendering size of the image from context (if pictures
are used in different sizes or come from different types of cameras etc.), 
so it's not a imagemagick-only thing.

> Say you have directories images/print that contain 300dpi images and
> images/screen that contain 100dpi images. Then you can use:
> \setupexternalfigures
>     [directory={images/print}]
> \startmode[screen]
> \setupexternalfigures
>     [directory={images/screen}]
> \stopmode
> Run with context --mode=screen to get low-resolution images.

except for the "mode" thing (thanks for that nice context example!!)
that's how my setup looks already!  though I'd like context (lua?) to shrink the images
(and maybe even write to some "cache" directory?  not really needed, but nice idea while typing;-)


"I hope to die                                      ___       _____
before I *have* to use Microsoft Word.",           0--,|    /OOOOOOO\
Donald E. Knuth, 02-Oct-2001 in Tuebingen.        <_/  /  /OOOOOOOOOOO\
                                                    \  \/OOOOOOOOOOOOOOO\
                                                      \ OOOOOOOOOOOOOOOOO|//
Harald Koenig                                           //  /     \\  \
koenig at tat.physik.uni-tuebingen.de                     ^^^^^       ^^^^^

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