User Guide

GNU Image Manipulation Program
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Parasite
A Parasite is additional data which may be written to an XCF file. A parasite is identified by a name, and can be thought
of as an extension to the other information in an XCF file.
Parasites of an image component may be read by GIMP plug-ins. Plug-ins may also define their own parasite names,
which are ignored by other plug-ins. Examples of parasites are comments, the save options for the TIFF, JPEG and PNG
file formats, the gamma value the image was created with and EXIF data.
Path
A Path is a contour composed of straight lines, curves, or both. In GIMP, it is used to form the boundary of a selection, or
to be stroked to create visible marks on an image. Unless a path is stroked, it is not visible when the image is printed and
it is not saved when the image is written to a file (unless you use XCF format).
See the Paths Concepts and Using Paths sections for basic information on paths, and the Path Tool section for information
on how to create and edit paths. You can manage the paths in your image with the Paths dialog.
PDB
All of the functions which GIMP and its extensions make available are registered in the Procedure Database (PDB).
Developers can look up useful programming information about these functions in the PDB by using the Procedure Browser.
PDF
PDF (Portable Document Format) is a file format which was developed by Adobe to address some of the deficiencies of
PostScript. Most importantly, PDF files tend to be much smaller than equivalent PostScript files. As with PostScript,
GIMP’s support of the PDF format is through the free Ghostscript libraries.
Pixel
A pixel is a single dot, or ‘picture element’, of an image. A rectangular image may be composed of thousands of pixels,
each representing the color of the image at a given location. The value of a pixel typically consists of several Channels,
such as the Red, Green and Blue components of its color, and sometimes its Alpha (transparency).
Plugin
Optional extensions for the GIMP. Plugins are external programs that run under the control of the main GIMP application
and provide specific functions on-demand. See Section
11.1 for further information.
PostScript
Created by Adobe, PostScript is a page description language mainly used by printers and other output devices. It’s also an
excellent way to distribute documents. GIMP does not support PostScript directly: it depends on a powerful free software
program called Ghostscript.
The great power of PostScript is its ability to represent vector graphics—lines, curves, text, paths, etc.—in a resolution-
independent way. PostScript is not very efficient, though, when it comes to representing pixel-based raster graphics. For
this reason, PostScript is not a good format to use for saving images that are later going to be edited using GIMP or another
graphics program.
Linux distributions almost always come with Ghostscript already installed (not necessarily the most recent version). For
other operating systems, you may have to install it yourself. Here are instructions for installing it on Windows:
• Go to the Ghostscript project page on Sourceforge [GHOSTSCRIPT].
• Look for the package gnu-gs or ghostscript (for non-commercial use only) and go to the download section.
• Download one of the prepared Windows distributions, such as gs650w32.exe or gs700w32.exe.
• Start the executable and follow the instructions of the installation procedure.
• Copy the executable gswin32c.exe from the bin directory of the Ghostscript installation to the Windows directory (or
any other directory that is contained in the PATH). As an alternative, advanced users can set an environment variable,
GS_PROG, to point to gswin32c.exe (e.g. C:\gs\gsX.YY\bin\gswin32c.exe).