KHTML Paged Media - Status Report

[Bert Bos]

On Tuesday 30 August 2005 15:54, Luciano Montanaro wrote:
> El Miércoles 24 Agosto 2005 20:48, Bert Bos escribió:
> > > The last ironic standard problem are websites importing their
> > > style-sheets with a "screen" media selector. This means the
> > > style-sheet doesn't apply for "print" media, basically producing
> > > an unstyled webpage. It appears to support broken web-sites a
> > > "screen" media selector should be treated as "all".
> >
> > Please don't do that. By trying to fix some people's errors now,
> > you break style sheets for other people, now and in the future.
>
> I'm really glad someone is working on this.
>
> Is there a plan to offer the option to the user to browse sites as a
> collection of pages instead of as a single long scroll?

W3C has two approaches for this (at least for HTML and XML documents). 
One already exists, though not in Konqueror (yet?); one is being 
investigated in some W3C's working groups for CSS and the mobile Web.

1) Let the browser emulate other media than 'screen'. The media that 
support page breaks are 'print', 'projection', 'tv' and 'handheld': 

  1a) The 'projection' mode may not be exactly what you want, though,
  because it is meant for slide projections and so people that write
  style sheets for this medium typically use very large fonts. Also, if
  a browser implements this medium, it typically only supports it in
  full-screen mode. You can try it out with Opera.

  1b) The 'handheld' media type is not guaranteed to be paged: it is up
  to the browser to run either in paged or continuous mode. The handheld
  emulation on Opera, for example, emulates a handheld in continuous
  mode. Ditto for Daniel Glazman's "small screen" extension for Firefox.
  But with some lobbying, some browser makers might be willing to
  provide a handheld emulator that can runs in paged mode.

  1c) The 'print' medium is for printers and although a browser can
  emulate it (typically called "print preview"), it is probably not
  exactly what you want, because the 'print' medium is not interactive.
  That means that CSS selectors like ':hover' or ':active' don't have
  any effect when in 'print' mode.

  1d) The 'tv' medium is primarily for TVs, as the name indicates. As
  for 'handheld', a browser running in 'tv' mode may be either paged or
  continuous. I don't know of any desktop browser that can emulate 'tv'
  mode, but there are standalone TV emulators. (I don't remember if they
  provide paged or continuous display, though.)

2) Another approach is to add the concept of stacks or tabs to CSS. That 
is currently being investigated (think of something like 'display: 
card'). The main reason is the limited space available on handheld 
screens, but if this ends up in CSS3, it will apply to all interactive 
media.

For approach (1) we have specifications and implementations, for (2) we 
are just in the stage of trying to see if we really need this and if so 
what the requirements are.

It would be nice if Konqueror could emulate not only a printer, but also 
other media. With the help of Alan's code for the 'print' medium, it 
can't be too hard to also emulate 'tv', 'projection' and 'handheld'...

(Even better would be support not only for media types, but for full 
Media Queries[1]. Then you could even have different styles depending 
on how wide or high your window is, among other things.)

[1] http://www.w3.org/TR/css3-mediaqueries



Bert
-- 
  Bert Bos                                ( W 3 C ) http://www.w3.org/
  http://www.w3.org/people/bos                               W3C/ERCIM
  bert at w3.org                             2004 Rt des Lucioles / BP 93
  +33 (0)4 92 38 76 92            06902 Sophia Antipolis Cedex, France