Ken Blake wrote:
On Tue, 28 May 2013 03:22:50 -0500, Ron Fey
wrote:

On Tue, 21 May 2013 20:17:48 +0800, xfile wrote:

I decided to have all of our company's outgoing documents to be
converted to PDF format first and added a standard line: For your
convenience, we have prepared the document in PDF format so you may view
and edit with any editor of your choice.
I've used a bunch of editors over the years but I don't think I've ever seen
one that can edit pdf files. Can you please name one or two?


Here are three that spring to mind:

Adobe Acrobat
Foxit Reader
WordPerfect

There are others.

If you're referring to the ability to just change text,
that in my mind is not a full editor. A true editor, is
quite a different animal. A true editor can deal with
anything, such as putting text along a spiral path,
drawing textured geometric shapes, being able to group
objects, or see order in a document, that did not
originally exist.

Because PDF is a programming language, it is difficult
to deal with the contents in an entirely satisfactory
manner.

PostScript is the precursor to PDF, and the best editor
I had there was Tailor for Mac. It did a decent job,
but still left you exposed to the infinite possibilities
of the PostScript language. There were still some editing
jobs, that took entirely too long, because the tool
could not organize the data in a useful way (too many
polygons all floating in space).

*******

If you want a test, try using LibreOffice, enter a
string of text that has a ligature (pair of letters
with tight spacing). For example, the two letters in
the picture in this article, can be expressed in
LibreOffice as a ligature. When LibreOffice saves
to a PDF file, those are output as a line segment
set of special glyphs (i.e. crude approximation
of letters). Now, feed that to your PDF editor.
Can you select those letters ? Yes ? No ? Maybe ?
I bet what happens, is the two close together letters,
turn into a sticky mess of line segment approximations
of the letters "Fl". And that's all because the tool
did not emit a regular font, with ligatures encoded
in the font in the regular way.

http://en.wikipedia.org/wiki/Typographic_ligature

For another test subject to edit, try this one.
It's not particularly difficult for an editor
to deal with this. This sample PDF is special, in
that the contents start life as a computer program.
This is not the "printed output" of some document.
It's an actual computer program, then passed through
distiller.

http://ecee.colorado.edu/~kuester/smith/smith.pdf

(Source - change extension to .txt and read how
they did it, in Notepad. As far as I know, the PDF
version is just a distillation of the PostScript source.)

http://ecee.colorado.edu/~kuester/smith/smith.ps

Now, your editor has to deal with crap like that.
The editor will have a hard time, dealing with the
entire spectrum of information sources, like hand
crafted code. The visual output of a PDF program,
is a side effect of a computer program running. What
a good editor will do, is recognize some programming
idioms, and do a better job of allowing you to select
elements in the document. A bad editor, leaves you
to deal with the complexity, on your own (select
one item at a time).

Paul