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RE: Nostradamus (was Re: FO. lists as tables)

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> -----Original Message-----
> From: crism@xxxxxxxxxxxxx [mailto:crism@xxxxxxxxxxxxx]
> Sent: Saturday, October 16, 1999 7:14 PM
> 
> [Steve Schafer]
> >[Chris Maden]
> >>No, portability means that if a European designer makes a 
> stylesheet that
> >>looks good on his A4 printer, I should be able to handle it 
> on my US letter
> >>printer without anything running off the edge.
> >
> >That's just one particular facet of portability. If the European
> >designer decides that the document should reformat itself
> >intelligently according to the media dimensions, then he should be
> >able to say so. If he wants the document to be paginated and laid out
> >in exactly the same way, regardless of the media dimensions, then he
> >should be able to say so. In the latter case, he has to take
> >responsibility for ensuring that the layout is compatible with a
> >variety of media dimensions, but it should still be his choice.
> 
> That's not portability.  It's what TeX calls "device 
> independence".  The
> 

Hmmm.  I think we're talking about several different things here that all
could reasonably be called aspects of portability.

	1.  Implementation portability: different implementations should
support the same interpretation of a given stylesheet, meaning, in practical
terms, that I can switch to a different implementation without needing to
change my stylesheets.

	2.  Device (resolution) portability: a given implementation's
interpretation of a given stylesheet should not vary across devices that
differ by resolution alone.  In practical terms, this means that I can
switch from a 300 dpi printer to a 1200 dpi printer without needing to
change my stylesheet.  (This should be refined to cover the color
capabilities of the device as well.)

	3.  Sylesheet generality: a given stylesheet should provide
satisfactory results across "presentation spaces" of different sizes (and
across different media?).  This means one stylesheet should "work" for both
letter-size and A4; by extension, it should "work" on a 72dpi monitor no
matter the size of the viewport.

Some other aspects that have not arisen explicitly in the thread:

	4.  Orientational independence:  use of the same stylesheet for both
horizontal and vertical Japanese text, for example.

	5.  Language portability: use of one stylesheet for documents in
different languages.  For example, use of a single stylesheet for English
text, vertical Japanese text, and Arabic text.

	6.  DTD generality: use of one stylesheet across multiple document
types.  DSSSL and XSL don't support this kind of generality, but it is
possible.  I suppose if you had a DSSSL-based system with lots of support
for architectural forms you might be able to get portability across DTDs
within an architecture.

Obviously (I hope) these aspects of portability are interrelated.  The
meaning of "interpretation" as used in item 1 depends on items 2 and 3.
Device portability can be defined in a number of ways, but I think we get
the cleanest and simplest language if isolate size from other device
characteristics, resolution in particular.  "Device independence" is
probably too broad for this usage, hence "resolution
independence/portability".  This should be considered distinct from
stylesheet generality, since the geometry of the presentation space is
fundamental to compositional constraints in a way that device resolution is
not.

> >>I should also be able to look at it on screen without 
> having to scroll
> >>back and forth, like I do with Acrobat.
> >
> >I don't follow you. What does that have to do with formatting?
> 
> Everything.  If you send me a picture of an 8-1/2x11 page 
> with 9-pt type,
> and I'm using a 640x480 monitor, I have to enlarge the page 
> and then scroll
> left and right for every line.  It gets real tired real fast. 
>  Give me the
> constraints you used to create that page, and let me apply them to my
> narrower page and bigger font, and I'll be very happy.

I think this would fall under the category of "stylesheet generality", but I
would restate it to focus entirely on composition.  Instead of "send me a
picture of" I would say "Send me an XML doc with a stylesheet designed for a
presentation space of 8-1/2x11 at a resolution of 1200 dpi; I want it to 'do
the right thing' on my 640x480 monitor so that I don't have to scroll etc."
Of course "do the right thing" will depend on the user's preferences, so
obviously that means the stylesheet language must be designed to accomodate
"locally-imposed" constraints, so that the user can stipulate the font size
etc. without re-doing the stylesheet.

-gregg


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