Sietse,
I have confirmed, after significant testing, that 'convert -density 72'
against existing non-png images produces the expected results in context
output pdf documents.
But I'm left with another problem, again something that becomes apparent
as the difference between having two output formats in my document
workflow: markdown -> pandoc -> html/text -> context tex -> pdf. This
time it's images that are too wide for the available textarea in the pdf
document. Now that the dpi is set, they display at the expected full
resolution, yet if they are greater than 6.5*72=438 pixels, they go over
the right margin. I know I can, individually, modify each
/externalfigure directive and add 'width=\textwidth', but that really is
a PITA. This document will have close to a hundred images.
I will investigate using a commandline script, exif data, and convert to
work through all of the images in the folder to scale/resize them so
that they fit in the PDF document margin width. I don't think that the
html version will suffer if I do this.
So, again, thanks for your help!
Best regards,
Guy S.
On 11/21/2012 02:36 PM, Sietse Brouwer wrote:
Guy wrote:
Well, that lead to an interesting experiment. I used convert to -resample a
set of images to 300dpi and redid the compile. They are all now too bod,
many off the right side of the page. Then did the same but set to 72. They
are still too big. Odd, from too small to too big.
I think you don't want -resample, but -density:
# density given in dpi
convert pic.jpg -density 72 pic-out.jpg
convert -density keeps the pixel size and changes the display size by
setting the density metadata.
convert -resample keeps the display size and changes the pixel size by
resampling at a certain density. (This explains why the picture
remained the same too-large size when you resampled at 72 and 300
dpi.)
Because you want to change the display size (and also because
resampling is a lossy process), I think you want -density.
As for the density value you want to use:
Your picture is 547px wide, so if you want it to display it 3 inches
wide you should set its density metadata to 547/3 = 183 dpi.
Does this work?
All the best,
Sietse
--
"There is only love, and then oblivion. Love is all we have
to set against hatred." (paraphrased) Ian McEwan
Guy Stalnaker, I^2@DOIT, 1210 West Dayton Street, Room 3209 CSS, Madison
WI 53719-1220, jstal...@wisc.edu, work 608.263.8035, cell 608.235.4718,
fax 608.265.6681, page page-...@watchdog.doit.wisc.edu
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