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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:18:32 ADT
Stephen Dennis (sdennis@svdltd.com)
Mon, 15 Jun 1998 22:09:36 -0700
PDF and HTML purposes are closely related...just like the purpose of
PostScript and PCL are closely related.
Both PostScript and PCL streams are generated in a "constrained" way by
printer memory and and printer CPU speed requirements. The only way to
dodge being "constrained" by printer CPU speed is to use a full-frame
buffer, which PostScript has typically embraced with some recent
exceptions and PCL has historically avoided and only provided as an
option with PCL 5.
These streams have operand-type things in them which temporarily take up
limited printer memory such as bitmaps, fonts, paths (PostScript). They
also have perator-type things things in them which tell the printer what
to do with those other things. Managing a printer's limited available
resources is something a printer driver and color seperation
post-processing steps must deal with.
A stream may be generated, communicated, and consumed all at the same
time and may not exist in it entirity at any particular moment. A stream
is generated and consumed from beginning to end.
You can add operators and extend the expressiveness of the language (and
make it more difficult for drivers to manage available printer
resources), but you cannot avoid dealing with the fact that printer
control languages are primarily about controlling a printer with finite
resources...not exchanging, storing, or retrieving information.
PDF and HTML on the other hand assume a reader is not paritcularly
limited by memory or CPU. They are both about taking an author's
intentions (in a general-enough way) and letting a rather intelligent
piece of code deal with the details of how to best present those
intentions. Their purpose is the same. You -can- view an author's A4
page on a differently-shaped and differently-sized display. PDF and HTML
are canoncial forms which must be approximated to each reader device.
Now if you want to argue that they are not the same animal just because
HTML doesn't do line-art, well I'd have'ta point at HTML's tag-oriented
CGM roots (which would include line-art), and point out that HTML is
exensible with COM objects that do line-art if you like or play movies
or anything else you care to do really.
On Monday, June 15, 1998 8:35 PM, Perry E. Metzger
[SMTP:perry@piermont.com] wrote:
>
> "Sprokkit Amhal" writes:
> > Perry E. Metzger <perry@piermont.com> wrote:
> > >PDF seems to be pretty universal right now, and pretty good for
most
> > >purposes.
> >
> > Is there any advantage of PDF over HTML?
>
> HTML is *not* a layout language. PDF is. PDF can express things like
> complicated math and vector diagrams -- HTML cannot.
>
> Perry
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:18:32 ADT