[Pkg-gmagick-im-team] Bug#737003: conversion to pdf silently fails for big paper formats

[Christian M. Amsüss]

On Wed, Jan 29, 2014 at 01:26:04PM +0100, Vincent Fourmond wrote:
>   Default resolution is 1 postcript point for 1 pixel. Hence you need
> an image of width or height 900 000. Even with a camera taking
> pictures of width 10 000 (ie a 80 MPixel camera), you still need 90 of
> those stitched horizontally to have problems ! I don't see how this
> could arise in real life.

the images i have at hand don't have resolutions set in the image
explicitly (would they be evaluated at all?), but give these results:

$ exiftool infile.jpg
[...]
X Resolution                    : 1
Y Resolution                    : 1
Resolution Unit                 : None
Software                        : Hugin 2013.0.0.4692917e7a55
[...]
Image Size                      : 12032x3013
$ convert infile.jpg outfile.pdf
$ pdfinfo outfile.pdf
[...]
Producer:       ImageMagick 6.7.7-10 2013-12-22 Q16 http://www.imagemagick.org
[...]
Page size:      866304 x 216936 pts

i don't know if a jpg's resolution can be any more unspecified than by
unsetting the unit. ([1] suggests there isn't; if there is, let me know
and i'll try to get hugin to export a properly undefined resolution).

the math of this implies 72pts per pixel (1 pixel per inch if i'm not
mistaken), which makes the critical size achievable with common cameras
and 360° panoramas.

[1] http://www.fileformat.info/format/jpeg/egff.htm

> Maybe just a warning could do ?

i don't know in which situation such a warning could be more useful than
an error (for these purposes, i'd call everythin an error that makes the
program return nonzero), but even a warning would be an enhancement.

thanks for considering the issue
chrysn

-- 
To use raw power is to make yourself infinitely vulnerable to greater powers.
  -- Bene Gesserit axiom
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