SGI (image file format)

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|formattype=electronic
 
|formattype=electronic
 
|subcat=Graphics
 
|subcat=Graphics
|extensions={{ext|sgi}}, {{ext|bw}}, {{ext|rgb}}, {{ext|rgba}}
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|extensions={{ext|sgi}}, {{ext|bw}}, {{ext|rgb}}, {{ext|rgba}}, others
 
|pronom={{PRONOM|x-fmt/140}}
 
|pronom={{PRONOM|x-fmt/140}}
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|wikidata={{wikidata|Q7514956}}
 
}}
 
}}
'''SGI''' (also known as '''IRIS''', and sometimes called '''RGB''' or '''Irix RGB''') is a raster image file format. The image may be uncompressed, or use [[Run-length encoding|RLE]] compression.
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'''SGI image''' (also known as '''IRIS''', and sometimes called '''RGB''' or '''Irix RGB''') is a raster image file format. It is associated with an image library used on Silicon Graphics workstations. The image may be uncompressed, or use [[Run-length encoding|RLE]] compression.
  
SGI probably stands for '''Silicon Graphics Image'''.
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== Format details ==
  
== Image types ==
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=== File structure ===
SGI supports the following image types:
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SGI image files start with a 512-byte fixed header, most of which is unused. If the image is uncompressed, the pixel data follows. Compressed images have a scan-line table, followed by the compressed pixel data.
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The pixel data is stored bottom-up.
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=== Image types ===
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The following image types are supported:
 
* Grayscale, 8 or 16 bits/sample
 
* Grayscale, 8 or 16 bits/sample
 
* RGB, 8 or 16 bits/sample
 
* RGB, 8 or 16 bits/sample
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* Colormapped (but no palette is stored in the file) (obsolete)
 
* Colormapped (but no palette is stored in the file) (obsolete)
 
* Colormap (file contains only a palette; no image) (obsolete)
 
* Colormap (file contains only a palette; no image) (obsolete)
 
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* Grayscale alpha images also exist, though they're not covered in the specification.
== Format ==
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SGI files start with a 512-byte fixed header, most of which is unused. If the image is uncompressed, the pixel data follows. Compressed images have a scanline table, followed by the compressed pixel data.
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The pixel data is stored from bottom-up, instead of top-down as in most image formats.
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== Identification ==
 
== Identification ==
SGI files begin with bytes <code>01 DA</code>.
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Files begin with bytes {{magic|01 DA}}.
  
 
== Specifications ==
 
== Specifications ==
* [ftp://ftp.sgi.com/graphics/grafica/sgiimage.html The SGI Image File Format, Version 1.00]
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* The SGI Image File Format, Draft version 0.97: [https://archive.org/details/ftp.sgi.com-archive ftp.sgi.com archive] → [https://archive.org/download/ftp.sgi.com-archive/ftp.sgi.com/sgi/graphics/SGIIMAGESPEC sgi/graphics/SGIIMAGESPEC]
* [ftp://ftp.sgi.com/graphics/SGIIMAGESPEC The SGI Image File Format, Draft version 0.97]
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* [http://paulbourke.net/dataformats/sgirgb/sgiversion.html The SGI Image File Format, Version 1.00]
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** Another copy: [https://archive.org/details/ftp.sgi.com_June2018 ftp.sgi.com_June2018] → [https://archive.org/download/ftp.sgi.com_June2018/ftp.sgi.com_June2018.tar/ftp.sgi.com%2Fsgi%2Fgraphics%2Fgrafica%2Fsgiimage.html ftp.sgi.com/sgi/graphics/grafica/sgiimage.html]
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* [http://paulbourke.net/dataformats/sgirgb/ SGI RGB Image Format]
  
 
== Software ==
 
== Software ==
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* [[Netpbm]]: pnmtosgi, sgitopnm
 
* [[Netpbm]]: pnmtosgi, sgitopnm
 
* [[ImageMagick]] (format named "SGI")
 
* [[ImageMagick]] (format named "SGI")
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* [[Tom's Viewer]]
 
* [http://svn.osgeo.org/grass/grass/branches/releasebranch_5_5/src.contrib/CERL/SGI/libimage/ libimage]
 
* [http://svn.osgeo.org/grass/grass/branches/releasebranch_5_5/src.contrib/CERL/SGI/libimage/ libimage]
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* {{Deark}}
  
 
== Sample files ==
 
== Sample files ==
 
* [http://ftp.funet.fi/index/graphics/packages/volvis/RGB.tar.Z RGB.tar.Z]
 
* [http://ftp.funet.fi/index/graphics/packages/volvis/RGB.tar.Z RGB.tar.Z]
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* {{DexvertSamples|image/sgi}}
  
== External links ==
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== Links ==
 
* [[Wikipedia:Silicon Graphics Image|Wikipedia article]]
 
* [[Wikipedia:Silicon Graphics Image|Wikipedia article]]
 
* {{EGFF|sgiimage|SGI Image File Format File Format Summary}}, from the [[Encyclopedia of Graphics File Formats]]
 
* {{EGFF|sgiimage|SGI Image File Format File Format Summary}}, from the [[Encyclopedia of Graphics File Formats]]
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[[Category:Silicon Graphics]]

Latest revision as of 18:24, 4 May 2024

File Format
Name SGI (image file format)
Ontology
Extension(s) .sgi, .bw, .rgb, .rgba, others
PRONOM x-fmt/140
Wikidata ID Q7514956

SGI image (also known as IRIS, and sometimes called RGB or Irix RGB) is a raster image file format. It is associated with an image library used on Silicon Graphics workstations. The image may be uncompressed, or use RLE compression.

Contents

 [hide

[edit] Format details

[edit] File structure

SGI image files start with a 512-byte fixed header, most of which is unused. If the image is uncompressed, the pixel data follows. Compressed images have a scan-line table, followed by the compressed pixel data.

The pixel data is stored bottom-up.

[edit] Image types

The following image types are supported:

  • Grayscale, 8 or 16 bits/sample
  • RGB, 8 or 16 bits/sample
  • RGBA, 8 or 16 bits/sample
  • RGB 3-3-2, 8 bits/pixel (obsolete)
  • Colormapped (but no palette is stored in the file) (obsolete)
  • Colormap (file contains only a palette; no image) (obsolete)
  • Grayscale alpha images also exist, though they're not covered in the specification.

[edit] Identification

Files begin with bytes 01 DA.

[edit] Specifications

[edit] Software

[edit] Sample files

[edit] Links

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