pnmtosir

Convert a PNM image to a SIR image

$ pnmtosir [path/to/input.pnm] > [path/to/output.sir]

pnmtosir [<pnmfile>]

pnmtosir is a Netpbm utility designed to transform images from the widely used Portable Anymap (PNM) format into the specific Set Of Lines (SIR) image format. The PNM family includes PBM (Portable Bitmap for black & white), PGM (Portable Graymap for grayscale), and PPM (Portable Pixmap for color) files, known for their simplicity and broad compatibility within the Netpbm suite.

The SIR format, conversely, is an older, often proprietary image format, notably associated with systems like SunVision. This command acts as a bridge, facilitating interoperability between modern Netpbm workflows and legacy systems or applications that require images in the SIR format.

pnmtosir reads the input PNM image either from standard input or a specified file and outputs the converted SIR image to standard output. This design makes it highly suitable for use in shell pipelines, where it can be combined with other Netpbm tools for comprehensive image processing tasks. It's a fundamental tool for format conversion, enabling data exchange across different image ecosystems.

The SIR format is considerably less common and more archaic compared to contemporary image formats, limiting its general applicability.

pnmtosir focuses solely on format conversion; it does not offer functionalities for image manipulation such as resizing, rotation, or color correction. For such operations, other Netpbm utilities should be used prior to or after conversion.

Input must be a valid PNM image. The command will report an error if the input file is malformed or in an unsupported format.

Output is always directed to standard output. To save the converted SIR image to a file, output redirection (e.g., > output.sir) is necessary.

The command reads a Portable Anymap (PNM) image from either standard input (if pnmfile is omitted) or a specified file. The resulting Set Of Lines (SIR) image is then written to standard output. This design is highly conducive to command-line piping, allowing pnmtosir to seamlessly integrate into complex image processing workflows.

Input: Portable Anymap (PNM), which includes Portable Bitmap (PBM), Portable Graymap (PGM), and Portable Pixmap (PPM) formats.

Output: Set Of Lines (SIR), an older proprietary image format often associated with SunVision.

pnmtosir is an integral part of the Netpbm project, which traces its origins back to Jef Poskanzer's PBMplus package, initially developed in the late 1980s. The Netpbm suite adheres to a Unix philosophy, providing numerous small, specialized tools designed to work together through pipes.

The inclusion of pnmtosir specifically addresses the historical need for interoperability with various proprietary image formats that were prevalent in specific computing environments, such as Sun workstations and their associated graphics software like SunVision.

It was officially added to the Netpbm suite in Netpbm 10.3 in August 2002. The command continues to be maintained as part of the Netpbm collection, ensuring ongoing support for converting to and from legacy formats and facilitating broader data compatibility.

sirtoppm(1), pnm(5), sir(5), netpbm(1)