Quartz Composer documents are called Compositions. Compositions are Binary Property Lists (though XML versions are also supported) with a filename extension .qtz, and a com.apple.quartz-composer-composition UTI. Patches, their connections, and their input port states are saved in the composition file. Images can be stored inside a composition as well, making for self-contained compositions with embedded graphics. By dragging a movie file into the Quartz Composer editor, a reference to the movie file is created, providing a changing image that can be connected to a renderer.
Compositions also store metadata such as composition author, copyright, and description. The user can also add arbitrary metadata items, if desired.
A wide variety of image formats are supported, including JPEG, JPEG2000, GIF, PNG, TIFF, TGA, OpenEXR, BMP, ICO, PDF, PICT, ICNS, and some raw digital camera types. Images are maintained in their native form for as long as possible before rasterizing for display. This means that it will keep vector images as vectors when cropping, scaling, rotating, or translating. This allows it to work with very large logical image dimensions without consuming large amounts of memory or processing time. Such functionality is most apparent when working with text-based images, or PDFs.
Version 3.0 added the ability to add annotations to areas of the composition, called notes. These notes parallel comments in other programming languages. Notes can be yellow, red, green, blue, or gray, and can overlap other notes.
Read more about this topic: Quartz Composer