derosa@motcid.UUCP (John DeRosa) (07/10/90)
I am having an arguement with a fellow worker about the difference between encapsulate postscript and postscript. We both agree what postscript is, i.e. a language of commands that can be sent to a postscript engine of one sort or another. He says that an EPS file is: "An Encapsulated Postscript file is merely a postscript file with two additional lines added at the begining: %!PS-Adobe-2.0 EPSF-1.2 %%BoundingBox: 0 0 612 792" I really don't know what it is. Will someone hazard a definition of EPS and PS? =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= = John DeRosa, Motorola, Inc, Cellular Infrastructure Division = = e-mail: ...uunet!motcid!derosaj = = motcid!derosaj@uunet.uu.net = = Applelink: N1111 = = I do not hold by employer responsible for any information in this message = = nor am I responsible for anything my employer may do or say. = =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
glenn@heaven.woodside.ca.us (Glenn Reid) (07/10/90)
In article <3911@crystal9.UUCP> derosa@motcid.UUCP (John DeRosa) writes: >I am having an arguement with a fellow worker about >the difference between encapsulate postscript and >postscript. > >He says that an EPS file is: "An Encapsulated Postscript >file is merely a postscript file with two additional >lines added at the begining: > > %!PS-Adobe-2.0 EPSF-1.2 > %%BoundingBox: 0 0 612 792" > >I really don't know what it is. I wrote the original (now antiquated) specification for Encapsulated PostScript files, so I'll hazard a guess. The remarks your friend made, I would say, are "necessary but not sufficient". Well, really, that is being too kind. They are a hack that *might* turn a file into an EPS file, if it just happened to already be one. But in general, just adding those comments won't do it. That is a little bit like making an Objective C program into a vanilla C program by changing the extension from ".m" to ".c" If you want a brief description that isn't quite the whole truth, an Encapsulated PostScript file is a well-behaved PostScript file that can be safely imbedded into another PostScript program as an illustration. This makes EPSF effectively a subset of the PostScript language. For instance, you cannot use the operator "erasepage" in an EPS file, because it would erase the entire page, including the rest of the page on which it was supposed to be an illustration. It also must only be a single page in length (imagine using a 52-page document as an illustration on page 3 of your newsletter). For a more complete definition, get a hold of the specification for EPS files from Adobe. I imagine you will get several follow-ups to your posting, one of which is sure to have the details on how to get the spec. Adding %! to the beginning of the PS file doesn't change anything about it. There are, however, many applications that support EPS files, and they won't even consider importing the file without the necessary header comments. NOTE: It is generally a bad idea to add comments to a file by hand. Those comments are a "guarantee" that the file adheres to the EPSF specification, and if the file doesn't adhere to it, you wouldn't want to make it tell untruths to the importing application. Sometimes you'll get lucky, often you won't. I hope this helps a little bit, although it doesn't seem all that clear when I glance back through it. Getting a hold of the spec from Adobe will make it the most clear. /Glenn -- Glenn Reid PostScript/NeXT consultant glenn@heaven.woodside.ca.us Independent Software Developer ..{adobe,next}!heaven!glenn Unparalleled Quality
woody@chinacat.Unicom.COM (Woody Baker @ Eagle Signal) (07/10/90)
In article <3911@crystal9.UUCP>, derosa@motcid.UUCP (John DeRosa) writes: > I am having an arguement with a fellow worker about > the difference between encapsulate postscript and > postscript. > > We both agree what postscript is, i.e. a language > of commands that can be sent to a postscript engine > of one sort or another. > > He says that an EPS file is: "An Encapsulated Postscript > file is merely a postscript file with two additional > lines added at the begining: > > %!PS-Adobe-2.0 EPSF-1.2 > %%BoundingBox: 0 0 612 792" in a sense it is. The above will allow you to import to some packages. EPS is really an attempt to fix some oversights in the language, by using structured comments. These comments mean nothing to the Postscript printer, but are designed to allow applications to do such things as allocate space on the page properly, know which fonts are needed etc. etc. Some print spoolers apparently utilize this information as well. There are several documents on the fileserver at adobe. I forget the exact way to get there, I think it is ps-file-server@adobe.com. Send a message send help and it will. Then you can get the complete EPS specs from the server. In the PC world, there is no use for EPS structuring comments, other than to allow certain software packages to import EPS files for display or printing. Print spoolers are essentialy not needed, and very little used, and those that are, are things like superspl from AST, and the like that are NOT postscript aware. Your friend is correct, in that the above 2 lines are the minimum required to qualify as "EPS", but as anyone who has tangled with the beast can tell you, they are not any guarantee of anything. Seems that each package likes a different subset of EPS, and there is very little acutal understanding between packages when it comes to EPS. Cheers Woody