ppmtopict

Convert a PPM image to a PICT file

$ ppmtopict [path/to/file.ppm] > [path/to/file.pict]

ppmtopict [-monochrome] [-verbose] [-alpha] [-force] [-bpp bpp] [ppmfile]

-monochrome
    Converts the input PPM image to a 1-bit monochrome PICT file. This is useful for black and white output.

-verbose
    Prints debugging information and progress messages to standard error during the conversion process.

-alpha
    Treats the input as a PAM (Portable Arbitrary Map) with an alpha channel and attempts to produce a PICT with alpha channel information. Note that PICT format does not natively support true alpha channels.

-force
    Forces the creation of a PICT file even if the input PPM is too wide for the PICT format's maximum width (typically 65535 pixels). This may result in an unreadable or malformed PICT file.

-bpp bpp
    Specifies the desired bits per pixel for the output PICT file. Common values include 1, 2, 4, 8, 16, 24, or 32. The command will attempt to match or approximate this depth.

ppmfile
    The path to the input PPM image file. If omitted, ppmtopict reads the PPM data from standard input (stdin).

ppmtopict is a utility from the Netpbm suite of graphics programs. Its primary function is to convert image files from the Portable Pixmap (PPM) format to the Apple PICT format.

The PPM format is a simple, flexible format for storing color images, widely used within the Netpbm tools. The Apple PICT format, on the other hand, is a graphics file format originally developed by Apple Inc. for its Macintosh operating system, supporting both bitmap and vector graphics.

This command is particularly useful for users who need to import Netpbm-generated images into Macintosh applications or environments that primarily support the PICT format. It handles color depth conversions and can output monochrome or full-color PICT images depending on the input and specified options. The tool reads a PPM image from standard input if no file is specified, and writes the PICT output to standard output, adhering to the standard Unix filter paradigm.

The PICT format has specific limitations, notably a maximum width of 65535 pixels; using -force beyond this limit can create invalid files. PICT does not natively support true alpha channels, so the -alpha option may produce non-standard PICT files. Due to PICT's older nature, modern systems and applications may have limited or no support for viewing these files, and palette-based PICTs are limited to 256 colors.

By default, ppmtopict reads its PPM image data from standard input (stdin) and writes the resulting PICT image to standard output (stdout). This design makes it highly suitable for use in shell pipelines, allowing it to be easily chained with other Netpbm commands or Unix utilities for complex image processing workflows.

The PICT format is a complex, proprietary image format from Apple, supporting both bitmap and vector graphics. ppmtopict primarily outputs bitmapped PICTs. Users should be aware that not all PPM features translate perfectly to PICT due to differences in color models, transparency handling, and other format specifics. The command strives to create a valid PICT, but exact visual fidelity may vary.

ppmtopict is an integral part of the Netpbm project, a comprehensive suite of graphics file conversion tools. The Netpbm collection originated from Jef Poskanzer's PBMPlus package in the late 1980s, adhering to the Unix philosophy of small, modular programs. Over decades, it has evolved through community contributions. ppmtopict was developed to facilitate interoperability between the versatile PPM format (native to Netpbm) and Apple's proprietary PICT format, which was prevalent in Macintosh environments, particularly in earlier computing eras. While PICT's usage has diminished, the tool remains a component of the robust Netpbm suite, reflecting its historical importance for cross-platform image handling.

picttoppm(1), ppm(5), pnm(5), netpbm(1)