Re: Emacs as word processor

[stephen@xemacs.org (Stephen J. Turnbull)]

Eli Zaretskii writes:

 > I don't think I understand what you mean by "depth of the character
 > box".  Emacs just computes the pixel y-coordinate of the next line
 > differently when this property is used.

[I'm sorry, the word I wanted was "descent", not "depth".  I don't
know if that helps, but it's more typographically precise.]

Sure, but where does the data for that computation come from?  It
comes from the font's metadata for the character (ascent [above
reference point], descent [below reference point], and offset [to next
glyph's reference point].  What can be done per character without
knowing *which* character is to set the descent to some value.  Then
the line's descent is the maximum of all descents of characters on the
line, as modified by the text property.

Another way to look at this is "what happens if *two* intervals
completely contained in the same line have *different* line-separation
properties?"  In TeX this is well-defined: use the largest descent of
any character on the line.  I suppose in Emacs it is the same.  But
this doesn't look very good in many cases.

 > Sorry, I don't see the difficulties.  Emacs already examines the
 > properties of each character when it displays text, and its word-wrap
 > and truncation/continuation decisions already take issues similar to
 > the above into consideration.

Of course it does.  The point is that some properties should be
specified per-character, and others should be specified for higher
level text units.  For the latter, using a text property that covers a
certain interval of characters that does not correspond to that unit
is horrible because it's going to confuse users.  The UI should make
that impossible.

 > >  > [Structured styles] is the source of all evil in Office.  The
 > >  > result is a terrible mess where the user ends up having no control
 > >  > on what is going on in her document (except for very short
 > >  > documents).  No, thanks.
 > > 
 > > No, that's not the problem.  The problem is that *Office separates
 > > editing of styles from editing of the document, making style editing
 > > the province of experts.  And *Office does a rather sucky job on
 > > things like indentation and mark formatting of bullet lists and
 > > enumerations (at least in Japanese documents).
 > 
 > No, the problem is that if you make changes in some part of text that
 > modify its typeface or indentation or properties of the numbered list,
 > these changes suddenly affect the entire document.

Really?  I've never seen that happen in any of Word, OpenOffice, or
LibreOffice.  The changes often do affect the containing block
(paragraph, table, etc), but not the whole document.  I usually wish
that would happen, but it doesn't ... unless you edit a style.

 > > Concretely, if you edit a section heading's style (eg, changing
 > > Helvetica to Times New Roman), Emacs could issue a query asking
 > > 
 > >     Do you want to edit just this instance?
 > >     Change font family to /Times New Roman/ in section headings at:
 > >     [All levels] [This level] [This heading only] [Cancel]
 > >     [ ] Review exceptional headings at affected levels
 > 
 > Nuisance, if done by default.  When I edit a piece of text, I mean to
 > edit only that piece of text.  If I want to edit all pieces of text
 > that use some style, I should say-so in advance.

Of course if you edit *text*, either the content or by applying or
removing a style, there should be no prompt, and I didn't propose that
there be one.  Did you notice that?

But if I edit the *style* of some particular object that occurs only
occasionally in the presentation (such as a section heading), that is
going to change the look and feel of the whole document *whether I
apply that change to all similar objects or not*.  Specifically, if I
*don't* apply it to the similar objects, the document's overall style
becomes less uniform.  That may be what you intend, and it may not be.

If you're a poet (say, e.e.cummings), I agree, lack of (conventional)
uniformity is High Art.  But in most organizations, lack of uniformity
in documents is not greatly appreciated, not by the bosses and enven
less so by the customers.  Applying a changed style to all objects
using that style should be the default.  It wouldn't be hard to define
the API and UI so that you could turn it off if you desire, and that
probably should be done.