Re: [Gimp-user] Ppm 16bit handling

2012-05-24 Thread Simon Budig
br...@buys.net.br (br...@buys.net.br) wrote:
 The thing is, when I open a 16bit tiff, Gimp *still* pops up the
 can't handle 16bit, information will be lost After opening the
 file I go to Image  Precision  and change to 16bit. But from what I
 understand, setting the file to 16bit *after* it was downed from 16 to
 8 doesn't help. Information was already discarded in the first
 conversion.

I am working at the TIFF plugin and some tiffs get loaded correctly
(while others are broken at the moment). Tiff is quite convoluted and
has a ton of different options. It is hard to wrap your mind around it.

 I don't understand: can't Gimp just open the file as it is, with no
 conversion whatsoever, since support to 16bit is there?

Well, unfortunately it is not that easy. There is a certain API
available for the file-plugins that transfers the image data to the Gimp
core. That API was only prepared to accept 8 bit images. The transition
of the core to a wider range of data formats did not change the old API,
since we wanted to keep compatibility for the plugin (or all plugins
would have disappeared simultaneously).

Hence we had to invent a second set of API functions that support the
new data formats. However, this means that the plugins which want to
make use of the new data formats need to be changed to use the new API.
In a lot of cases this is quite easy and means less code in the plugins,
but the changes have to be done and it is real work.

Porting the p*m-Plugin (plug-ins/common/file-pnm.c) should be easy. The
file-format is as simple and straight-forward as it gets. If you want to
dabble with development and help with the progress of Gimp you are
welcome to take a shot at it. If you catch me in IRC (#gimp, nomis) I'll
be glad to give assistance.

Have fun,
Simon

-- 
  si...@budig.de  http://simon.budig.de/
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Re: [Gimp-user] Ppm 16bit handling

2012-05-24 Thread bruno
  

On Thu, 24 May 2012 10:27:30 +0200, Simon Budig wrote: 


br...@buys.net.br [1] (br...@buys.net.br [2]) wrote:
 
 The thing is,
when I open a 16bit tiff, Gimp *still* pops up the can't handle 16bit,
information will be lost After opening the file I go to Image 
Precision and change to 16bit. But from what I understand, setting the
file to 16bit *after* it was downed from 16 to 8 doesn't help.
Information was already discarded in the first conversion.
 
 I am
working at the TIFF plugin and some tiffs get loaded correctly
 (while
others are broken at the moment). Tiff is quite convoluted and
 has a
ton of different options. It is hard to wrap your mind around it.
 

I don't understand: can't Gimp just open the file as it is, with no
conversion whatsoever, since support to 16bit is there?
 
 Well,
unfortunately it is not that easy. There is a certain API
 available
for the file-plugins that transfers the image data to the Gimp
 core.
That API was only prepared to accept 8 bit images. The transition
 of
the core to a wider range of data formats did not change the old API,

since we wanted to keep compatibility for the plugin (or all plugins

would have disappeared simultaneously).
 
 Hence we had to invent a
second set of API functions that support the
 new data formats.
However, this means that the plugins which want to
 make use of the new
data formats need to be changed to use the new API.
 In a lot of cases
this is quite easy and means less code in the plugins,
 but the changes
have to be done and it is real work.
 
 Porting the p*m-Plugin
(plug-ins/common/file-pnm.c) should be easy. The
 file-format is as
simple and straight-forward as it gets. If you want to
 dabble with
development and help with the progress of Gimp you are
 welcome to take
a shot at it. If you catch me in IRC (#gimp, nomis) I'll
 be glad to
give assistance.
 
 Have fun,
 Simon

Hi Simon!
That´s very friendly
of yours to reply in such detail. Now I feel like my first 
email was a
little clientish. Sorry for that. Gimp isn´t a private company.

I am
not of much help as a coder, but I can provide files and give
feedback
in testing.

Good news is, since you said you are working in
16bit tiff, when its done, 
it will be huge. Tiff is an important bridge
for those of us converting from raw.

Other good news is, I was able to
load, work and save a 16bit png file, following
this
post:
http://libregraphicsworld.org/blog/entry/gimp-2.8-released-next-version-to-get-high-bit-depth-precision

The
file was converted from tiff to png with 'convert', and opens without
the 
loose data notification. After opening, the precision is indeed set
to 16bit.

All the best! 

Bruno

  

Links:
--
[1]
mailto:br...@buys.net.br
[2] mailto:br...@buys.net.br
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Re: [Gimp-user] Ppm 16bit handling

2012-05-23 Thread br...@buys.net.br

On 05/07/12 06:04, Simon Budig wrote:

br...@buys.net.br (br...@buys.net.br) wrote:

I noticed that when I open a 16bit ppm in GIMP 2.8, the file opens
without the 'gimp can't handle 16bit, it will loose data, etc...'
notification. But if I open a tiff version of the very same raw
file, the notification does pop up. My understanding is that current
GIMP 2.8 can't handle 16bit, regardless of file format. Is that
right?

Yes, these warning dialogs are generated by the file-format plugin and
it seems the ppm plugin just silently discards data.

Gimp 2.8 is limited to 8 bit per channel, but if you feel adventurous
you are invited to try the current git version of babl/gegl/gimp and
experiment with the new high-bit-depth support. This still is strictly
unstable and has an inconsistent UI in lots of places. It is fun though
:)

I hope this helps,
 Simon

Hi,
So after a bunch of package installing and compiling, I am successfully
running Gimp 2.9.1 from git, on debian wheezy.
The thing is, when I open a 16bit tiff, Gimp *still* pops up the can't 
handle 16bit,
information will be lost After opening the file I go to Image  
Precision  and change
to 16bit. But from what I understand, setting the file to 16bit *after* 
it was downed
from 16 to 8 doesn't help. Information was already discarded in the 
first conversion.
I don't understand: can't Gimp just open the file as it is, with no 
conversion whatsoever, since

support to 16bit is there?

Thanks much,


Bruno

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Re: [Gimp-user] Ppm 16bit handling

2012-05-23 Thread Liam R E Quin
On Wed, 2012-05-23 at 23:34 -0300, br...@buys.net.br wrote:

 I don't understand: can't Gimp just open the file as it is, with no 
 conversion whatsoever, since support to 16bit is there?

Yes - all it takes is programming, code to handle each format at higher
bit depths. Patches are generally welcomed...

Liam

-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/
Ankh: irc.sorcery.net irc.gnome.org freenode/#xml

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