From: Joaquín Cuenca Abela (cuenca@pacaterie.u-psud.fr)
Date: Thu Aug 08 2002 - 15:06:11 EDT
On Thu, 2002-08-08 at 19:21, Dom Lachowicz wrote:
>
> > 4) layout independance for the years to come: if we go
> > the integer units way, we prevent any numerical
> > problems. If we go the floating point way, slight
> > changes in the way we calculate something, may change
> > the result due to numerical instability, and thus it
> > may affect layout. Before you consider this point as
> > a fundamental one, take in account that we've already
> > changed the layout of the user documents from version
> > to version for much lamer reasons, and we've not
> > changed it in "subtle" ways, but in rather radical
> > ways.
>
> This isn't a *huge* problem. Word Processor documents are allowed to
> look (and layout) slightly differently between versions and between
> platforms. Of course, we should try to keep these differences at a
> minimum, but there are some other reasons why things can and will look
> differently no matter what we do:
Here I disagree. IMO, Word Processors are *not* allowed to layout
differently, and if the user has all the fonts required, then the
document should render exactly identically, whatever version you use.
*But*, I'm not going to worry, and to take the pain of use integer
calculations in the layout if we're still going to change the layout for
other, much lamer, reasons.
I will start worrying about this problem, when I will see AbiWord laying
out documents exactly the same way for years except a little problem
here and there due to numerical instabilities.
> * Different fonts on different platforms (we don't and won't embed
> fonts like PDFs)
why "won't"? I was hopping to add something in this sense.
Of course, it's more difficult to us than to pdf, because we should
embed enough glyphs to render the text *and* to leave the user edit it.
But I see it as a desired feature (btw, word does it)
> * Slight/Major changes in the layout engine
This one is a good point. I don't see how are we going to preserve
layout in old documents if we change to a line breaker as, for instance,
the TeX one.
> * Should we ever support leading and kerning properly
that should be marked in the document, and thus we will still layout
chars that are not marked to kern without kerning. That should not
affect layout of old documents.
> I personally don't care if you use floats or integers, but please be
> consistent. I think that's more important than anything else.
I was a bit more pro-float, but seeing Jody post (ie. this issue may be
more important for tables than for simple text) puts me in a middle
zone.
Also the fact that TeX picked integer calculations, getting a formidable
layout stability over the years has a certain weight in my mind.
Still hesitating,
-- Joaquín Cuenca Abela cuenca@pacaterie.u-psud.fr
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