Encapsulated PostScript
| Filename extension | .eps |
|---|---|
| Internet media type | application/postscript, application/eps, application/x-eps, image/eps, image/x-eps |
| Type code | EPSF TEXT |
| Uniform Type Identifier (UTI) | com.adobe.encapsulated-postscript |
| Type of format | Vector image format |
| Extended from | PostScript |
Encapsulated PostScript (EPS) is a DSC-conforming PostScript document with additional restrictions which is intended to be usable as a graphics file format. In other words, EPS files are more-or-less self-contained, reasonably predictable PostScript documents that describe an image or drawing and can be placed within another PostScript document. Simply, an EPS file is a PostScript program, saved as a single file that includes a low-resolution preview "encapsulated" inside of it, allowing some programs to display a preview on the screen.
At minimum, an EPS file contains a BoundingBox DSC comment, describing the rectangle containing the image described by the EPS file. Applications can use this information to lay out the page, even if they are unable to directly render the PostScript inside.
EPS, together with DSC's Open Structuring Conventions, form the basis of early versions of the Adobe Illustrator Artwork file format.
A number of programs will save or convert text and vector art to EPS format, including:
Many image converter programs can create EPS files containing the pixels of the image.
An EPS file is a stream of generic PostScript printing commands. Thus many PostScript printer drivers have an option to save as EPS, or to add EPS DSC information to their output which you can "print to file". Saving as EPS was a feature of Microsoft's PSCRIPT.DRV Windows printer driver and Adobe's ADOBEPS.DRV Windows printer driver for Windows versions prior to Windows 2000.
EPS files also frequently include a preview picture of the content, for on-screen display. The idea is to allow a simple preview of the final output in any application that can draw a bitmap. Without this preview the applications would have to directly render the PostScript (PS) data inside the EPS, which was beyond the capabilities of most machines until recently.
When EPS was first implemented, the only machines widely using PostScript were Apple Macintoshes. These machines could not directly render the PostScript, which presented Adobe with the problem of how to provide a preview image while also including the actual PS version for the printer. On the Mac this turned out to be easy to solve, as the Mac file system includes two parts (known as forks) that are logically referred to as one file. By placing the PostScript in the data fork and a standard Mac PICT resource in the resource fork, both images could be moved about together invisibly as if they were one file. While a PICT preview often contains a bitmap it could also contain a vector representation of the whole image, providing very high quality previews.
...
Wikipedia