Paul Smith wrote:
On 6/14/06, Stephen Harris <[EMAIL PROTECTED]> wrote:
> Thanks, David and Georg. In particular, I am trying to find a tool to
> work on Linux. Gimp is a Linux application, but maybe there is already
> a Linux equivalent of StripFile:
>
> http://www.nuetools.co.uk/stripfile.html
>
> I will ask for it on the Fedora mailing list.
Stripfile succeeds mainly by removing embedded comments/text.
http://files.linuxforum.com/man/jpegtran.1.php
"jpegtran also recognizes these switches that control
what to do with "extra" markers, such as comment blocks:
-copy none
Copy no extra markers from source file. This setting
suppresses all comments and other excess baggage present
in the source file.
-optimize
Perform optimization of entropy encoding parameters.
-trim Drop non-transformable edge blocks."
http://mapivi.sourceforge.net/mapivi.shtml
http://rpmfind.net/linux/RPM/suse/9.0/i386/suse/i586/ungifsicle-1.39-34.i586.html
http://www.intuitive.com/coolweb/FAQ/giftrans-doc.html
giftrans converts any GIF file into a GIF89a. Allows for
setting the transparent or background color, changing colors,
adding or removing comments. Also code to analyze GIF contents.
SH: These all work on Linux but only MapIvi has a nice interface.
embedded JPEG comments (single and multiple comments are supported):
* display
* add, edit, copy, join or remove
Thanks, David and Stephen. Meanwhile, a gentleman has suggested me
pngcrush, which I have tried with significant size reduction of png
images, with no loss of quality. Please, have a look at:
http://pmt.sourceforge.net/pngcrush/
It is command line oriented and also works on MS Windows.
There seems to be a quite recent release also.
Paul
SH: After nosing around into Netpbm, I looked at ImageMagick:
http://www.cit.gu.edu.au/~anthony/graphics/imagick6/formats/
Reading JPEG Images
+profile '*'
-strip
"JPEG images as saved by digital cameras, scanning
software and other image processing software like "photoshop"
will often add large profiles of "program comments" to JPEG
images. Either of these options will remove those profiles
from a image that was read in.
Non-ImageMagick JPEG Processing
As re-writing a JPEG image results in a degrading of image
quality (unless lossless compression is used) the JPEG image
library provides a number of special programs that can
manipulate the image, without loss of quality.
These command will also be generally a lot faster than IM
equivalents, as they do not have to do as much processing
of the image.
Examples of these commands include...
read comments: rdjpgcom image.jpg
remove comments: wrjpgcom -replace -comment '' image.jpg > new_image.jpg
remove profiles: jpegtran -copy none image.jpg > new_image.jpg
-----------------------------------------------------------------
Here is an example of a shell command to convert all your of PNG
files (named *.png) to JPEG files named *.jpg:
for i in *.png; do pngtopnm $i | ppmtojpeg >`basename $i .png`.jpg; done
jpegtran Does some of the same transformations as Netpbm is famous for,
but does them specifically on JPEG files and does them without loss of
information."
-------------------
SH: One would imagine that pngcrush would be better specialized to
do conversions than using a Netpbm command or some piped commands.
Jpeg appears to have the best stripping options. I don't know if
converting other image formats to jpeg for stripping is clever.
Regards,
--
Stephen
Topic ontology recapitulates entropic philology.
