Hi,

I'm just trying to get a better understanding of the XCF file format and to review and update the XCF spec (/devel-docs/xcf.txt).

I've got some questions:

1) Some properties are denoted with "essential", "editing state", "not editing state, but not really essential either". I have problems understanding these remarks. What did Henning Makholm mean?

2) I found the property PROP_ITEM_PATH in the code, which is not yet in the spec (I'll add it). The code reads that it is a list of pointers, represented as uint32 integers and somehow in the context of layers. However, I don't get what this is for and what the property values mean.

3) The XCF file holds (for unclear historical reasons) a level-of-detail hierarchy, but we only use the lowest hierarchy level of it and other XCF consumers are told to do the same.
For my understanding this looks like a mipmap. Would using it to save an image pyramid or the thumbnail for the File dialogs get us some benefits?

4) What will happen with the format after the GEGL port? AFAIK the ORA format will play a big role in the GEGL context (correct me if I'm wrong). Will XCF be dropped then or will ORA then be yet another import/export format like PSD etc.?

5) The document shows that the layer modes 'Overlay' and 'Soft light' are identical.
If this information is still valid - is this state subject to change in GEGL? Should we continue providing two different names for the same thing?

Thank you in advance,

Sven

Hi,

On 12.7.2014 at 4:31 AM Ed . wrote:

I believe that the smart move is to go with the code if the doc disagrees, given the age of the doc.

hmm, this doesn't really help with my questions, as this is what I'm already doing.

I would like to open discussion on a format of how to store GIMP images in an Open Document Format of some kind.

The ORA format (see 4) has this in mind. See also http://freedesktop.org/wiki/Specifications/OpenRaster/ ?

However, thank you for your nice attempt to help.

@Mitch, Nomis, Drawoc etc. - can you GIMP old stagers tell me a bit?

Kind regards,

Sven

-----Original Message----- From: scl Sent: Friday, July 11, 2014 6:54 PM
To: gimp-developer
Cc: henning@makholm.net
Subject: [Gimp-developer] Questions about the XCF file format spec

Hi, [...]
4) What will happen with the format after the GEGL port? AFAIK the ORA format will play a big role in the GEGL context (correct me if I'm wrong). Will XCF be dropped then or will ORA then be yet another import/export format like PSD etc.?

Hi,

I've updated the XCF format spec at https://git.gnome.org/browse/gimp/tree/devel-docs/xcf.txt?h=osx-build

It's currently in the OSX-build branch, but on its way into 2.8 and master soon.
So, if anybody wants to have a look on it - feedback is welcome (and answers to my open questions, too :-) )

Kind regards,

Sven