OpenRaster/File Layout Specification
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- Status: what is already specified is pretty much final
Contents |
Storage
OpenRaster files have the file name extension .ora. The data is stored as ZIP file.
Note that ZIP can use a different compression algorithm on a per-file basis. Only DEFLATED and STORED should be used. Filenames are case-sensitive and must be UTF-8 encoded.
- Should we enforce use of the 64bit extension (for files larger than 4GB)? --Maxy 11:23, 24 December 2008 (UTC)
Required Files
mimetype
The first file in this ZIP must be called "mimetype" without extension and must be STORED without compression. This file contains the string "image/openraster" without newline.
stack.xml
This is the UTF-8 encoded XML file from the Layers Stack Specification.
Optional Files
data
This directory is (by convention) where data files are usually stored. Files must be referenced by their full path, eg. "data/layer2.png" inside stack.xml.
All files inside this directory should be referenced from somewhere. Well known filename extensions (like .png) should be lowercase.
Thumbnails/thumbnail.png
This file is highly reccommended, in order to get previews in file browsers.
It should contain the final (possibly cropped) image without any frame or decoration. It must be a non-interlaced PNG with 8bits per channel of at most 256x256 pixels. It should be as big as possible without upscaling or changing the aspect ratio. This file must not be referenced in any .xml file.
palette.gpl or palette.xml (MyPaint proposal)
Color swatches set (as additional info for editing application) can be saved in palette.gpl in Gimp's .gpl format, or in palette.xml in XML format. XML format should base on Swatches_-_colour_file_format/Draft. --Portnov 19:31, 30 September 2009 (UTC)
Related Links
- OpenRaster/Desktop Integration for the mime entry, and a list of programs using the thumbnails
- Thumbnail Managing Standard
