AlanHorkan is currently certified at Master level.

Name: Alan Horkan
Member since: 2002-09-14 15:39:05
Last Login: 2011-07-18 01:29:52

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Homepage: http://advogato.org/person/AlanHorkan/

Notes:

Code may not be my main contribution to Open Source but I make myself useful with a little bit of everything (usability, bugfinding, general helpful encouragement).
Alan particularly likes cross platform software like AbiWord, Mozilla, OpenOffice, and projects like Inkscape, Dia> and the GNU Image Manipulation Program.

Alan is moderator of the Gnome Usability Mailing list.
Alan can often be found on irc.gnome.org usually on the channel #abiword.
Alan's email address is horkan a at maths dot tcd dot ie
Alternatively you can try contacting alanhorkan at Gmail or Yahoo! although these addresses get checked far less often.

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OpenRaster Python Plugin

Thanks to developers Martin Renold and Jon Nordby who generously agreed to relicense the OpenRaster plugin under the Internet Software Consortium (ISC) license (it is a permissive license, it is the license preferred by the OpenBSD project, and also the license used by brushlib from MyPaint). Hopefully other applications will be encouraged to take another look at implementing OpenRaster.

The code has been tidied to conform to the PEP8 style guide, with only 4 warnings remaining, and they are all concerning long lines of more than 80 characters (E501).

The OpenRaster files are also far tidier. For some bizarre reason the Python developers choose to make things ugly by default, and neglected to include any line breaks in the XML. Thanks to Fredrik Lundh and Effbot.org for the very helpful pretty-printing code. The code has also been changed so that many optional tags are included if and only if they are needed, so if you ever do need to read the raw XML it should be a lot easier.

There isn't much for normal users unfortunately. The currently selected layer is marked to the OpenRaster file, and also if a layer is edit locked. If you are sending files to MyPaint it will correctly select the active layer, and recognize which layers were locked. (No import back yet though.) Unfortunately edit locking (or "Lock pixels") does require version 2.8 so if there is anyone out there stuck on version 2.6 or earlier I'd be interested to learn more and I will try to adjust the code if I get any feedback.
I've a few other changes that are almost ready but I'm concerned about compatibility and maintainability so I'm going to take a bit more time before releasing those changes.

The latest code is available from the OpenRaster plugin gitorious project page.

Syndicated 2015-03-23 18:35:16 from Alan Horkan

Krita 2.9

Congratulations to Krita on releasing version 2.9 and a very positive write-up for Krita by Bruce Byfield writing for Linux Pro Magazine.

I'm amused by his comment comparing Krita to "the cockpit of a fighter jet" and although there are some things I'd like to see done differently* I think Krita is remarkably clear for a program as complex as it is and does a good job of balancing depth and breadth. (* As just one example: I'm never going to use "File, Mail..." so it's just there waiting for me to hit it accidentally, but far as I know I cannot disable or hide it.)

Unfortunately Byfield writes about Krita "versus" other software. I do not accept that premise. Different software does different things, users can mix and match (and if they can't that is a different and bigger problem). Krita is another weapon in the arsenal. Enjoy Krita 2.9.

Syndicated 2015-02-25 23:42:50 from Alan Horkan

OpenRaster Python Plugin

OpenRaster Python Plugin

Early in 2014, version 0.0.2 of the OpenRaster specification added a requirement that each file should include a full size pre-rendered image (mergedimage.png) so that other programs could more easily view OpenRaster files. [Developers: if your program can open a zip file and show a PNG you could add support for viewing OpenRaster files.*]

The GNU Image Manipulation Program includes a python plugin for OpenRaster support, but it did not yet include mergedimage.png so I made the changes myself. You do not need to wait for the next release, or for your distribution to eventually package that release you can benefit from this change immediately. If you are using the GNU Image Manipulation Program version 2.6 you will need to make sure you have support for python plugins included in your version (if you are using Windows you wont), and if you are using version 2.8 it should already be included. (If the link no longer works, see instead https://gitorious.org/openraster/gimp-plugin-file-ora/ as I hope the change will be merged there soon.)

It was only a small change but working with Python and not having to wait for code to compile make it so much easier.

* Although it would probably be best if viewer support was added at the toolkit level, so that many applications could benefit.

Syndicated 2015-02-18 19:14:34 from Alan Horkan

OpenRaster and OpenDocument: Metadata

OpenRaster is a file format for the exchange of layered images, and is loosely based on the OpenDocument standard. I previously wrote about how a little extra XML can make a file that is both OpenRaster and OpenDocument compatible. The OpenRaster specification is small and relatively simple, but it does not do everything, so what happens if a developer wants to do something not covered by the standard? What if you want to include metadata?

How about doing it the same way as OpenDocument, it does not have to be complicated. OpenDocument already cleverly reused the existing Dublin Core (dc) standard for metadata, and includes a file called meta.xml in the zip container. A good idea worth borrowing, a simplified example file follows:

Sample OpenDocument Metadata[Pastebin]

(if you can't see the XML here directly, see the link to Pastebin instead.)

I extended the OpenRaster code in Pinta to support metadata in this way. This is the easy part, it gets more complicated if you want to do more than import and export within the same program. As before the resulting file can renamed from .ora to .odg and be opened using OpenOffice* allowing you to view the image and the metadata too. The code is Pinta OraFormat.cs is freely available on GitHub under the same license (MIT X11) as Pinta. The relevant sections of are "ReadMeta" and "GetMeta". A Properties dialog and other code was also added, and I've edited a screenshot of Pinta to show both the menu and the dialog at the same time:

[* OpenOffice 3 is quite generous, and opens the file without complaint. LibreOffice 4 is far less forgiving and gives an error unless I specifically choose "ODF Drawing (.odg)" as the file type in the Open dialog]

Syndicated 2015-02-13 00:38:44 from Alan Horkan

OpenRaster and OpenDocument

OpenRaster is a file format for layered images. The OpenRaster specification is small and relatively easy to understand, essentially each layer is represented by a PNG image, and other information is contained written in XML and it is all contained in a Zip Archive. OpenRaster is inspired by OpenDocument.
OpenDocument is a group of different file formats, including word processing, spreadsheets, and vector drawings. The specification is huge and continues to grow. It cleverly reuses many existing standards, avoiding repeating old mistakes, and building on existing knowledge.

OpenRaster can and should reuse more from OpenDocument.



It is easy to say but putting it into practice is harder. OpenDocument is a huge standard so where to begin? I am not even talking about the OpenDocument Graphics (.odg) specifically but more generally than that. It is best that show it with an example. So I created an example OpenRaster image with some fractal designs. You can unzip this file and see that like a standard OpenRaster file it contains:


fractal.ora  
 ├ mimetype
 ├ stack.xml
 ├ data/
 │  ├ layer0.png
 │  ├ layer1.png
 │  ├ layer2.png
 │  ├ layer3.png
 │  ├ layer4.png
 │  └ layer5.png
 ├ Thumbnails/
 │  └ thumbnail.png
 └ mergedimage.png

It also unusually contains two other files manifest.xml content.xml. Despite the fact that OpenDocument is a huge standard the minimum requirements for a valid OpenDocument file comes down to just a few files. The manifest is a list of all the files contained in the archive, and content.xml is the main body of the file, and does some of the things that stack.xml does in OpenRaster (for the purposes of this example, it does many other things too). The result of these two extra files, a few kilobytes of extra XML, is that the image is both OpenRaster AND OpenDocument "compatible" too. Admittedly it is an extremely small tiny subset of OpenDocument but it allows a small intersection between the two formats. You can test it for yourself, rename the file from .ora .odg and LibreOffice can open the image.

To better demonstrate the point, I wanted to "show it with code!" I decided to modify Pinta (a Paint program written in GTK and C#) and my changes are on GitHub. The relevant file is Pinta/Pinta.Core/ImageFormats/OraFormat.cs which is the OpenRaster importer and exporter.

This is a proof of concept, it is limited and not useful to ordinary users. The point is only to show that OpenRaster could borrow more from OpenDocument. It is a small bit of compatibility that is not important by itself but being part of the larger group could be useful.

Syndicated 2014-12-12 04:03:51 from Alan Horkan

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