SGI

SGI is Silicon Graphics' image format (.rgb, .rgba, .bw, .sgi): a 512-byte header, then one to four channels of 8 or 16-bit samples, each channel a plane of bottom-up rows, plain or run-length coded. It reads and writes through the Egami.Formats.Extended package: register it with WithSgi() or WithExtendedFormats() (Extended formats).

Reads	1 to 4 channels (gray, gray and alpha, RGB, RGBA) of 8 or 16 bits, plain or coded, dimension 1, 2 or 3; coded rows in any order in the file; further channels are skipped with a Sgi.ChannelsSkipped warning
Writes	The raster's own channels (gray, gray and alpha, RGB or RGBA) and depth (16-bit above 8 bits a channel), coded unless SgiWriterOptions.Rle is off, with the image name from SgiDetails
Natural pixel type	Gray8, GrayAlpha8, Rgb8 or Rgba8, or their 16-bit forms
FormatInfo	SgiFormat.Info: name SGI, extensions .sgi, .rgb, .rgba, .bw, .int, .inta, MIME types image/sgi and image/x-rgb

// SGI codes its rows by default; Sun raster writes them plain unless asked.
using (FileStream sgi = File.Create("duck.rgb"))
{
    image.Save(sgi, SgiFormat.Info, new SgiWriterOptions { Rle = false });
}

using (FileStream sun = File.Create("duck.ras"))
{
    image.Save(sun, SunRasterFormat.Info, new SunRasterWriterOptions { Rle = true });
}

The planes are stored bottom-up and the coded rows may lie anywhere, so a decode reads the file whole and then hands out rows, and the writer keeps the coded rows in memory until the last one. A file that ends early leaves the rows it lacks transparent black with the warning Sgi.RowsMissing, and a damaged coded row is cut short with Sgi.RowDamaged. SGI keeps alpha and 16-bit samples but no metadata. Images are at most 65,535 pixels on a side.