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Re: pause-before property for presentations

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 12 Jul 2002 23:25:59 +0100
Message-ID: <3D2F5777.5070604@hixie.ch>
To: Dave Raggett <dsr@w3.org>
Cc: Val Sharp <val@valsharp.co.uk>, www-style@w3.org

Dave Raggett wrote:
 >> I also don't understand what this property _does_. Does it make elements
 >> invisible? How? What order do elements reappear? etc.
 >
 > It breaks pages up into sections. When you are in projection mode (as defined
 > my the @media mechanism), the browser would require the user to take some
 > implementation dependent action (e.g. to hit the space bar) before it would
 > reveal the next section.

Ok... sample use case document:

    <presentation>
     <slide>
      <title> Title of Slide 15 </title>
      <ol>
       <li> <p> First bullet point in slide 15. </p> </li>
       <li>
        <p> Second bullet point. </p>
        <note> Note about the second bullet point. </note>
       </li>
       <li> <p> Third bullet point. </p> </li>
      </ol>
      <footer>
       <number> Slide 15/43 </number>
       <author> A. N. Other </author>
      </footer>
    </document>

The stylesheet which would go with it:

    presentation, slide, title, ol, p, note { display: block; }
    slide { page-break-before: always; }
    title { font-size: 2em; }
    li { display: list-item; pause-before: always; }
    li:first-child { pause-before: avoid; }
    footer { display: table; width: 100%; }
    number, author { display: table-cell; }
    author { text-align: right; }

Would the footer be visible the whole time?


 > The process is repeated until the end of the page is reached and the page is
 > flipped to the next one. The hidden sections would still take up the same
 > screen real estate as when they are revealed.

So they are hidden? (Their 'visibility' property computes to 'hidden' until the
element is shown?) That would work, although it is a little limited.


 > The hard work for the implementation is dividing the document into pages and
 > supporting navigation between them. Once you have that, the section mechanism
 > by contrast is comparatively simple to support.

Indeed the two are orthogonal.


 > Note that I have used the term "section" but another term might be more
 > appropriate to avoid confusion with larger scale document structure, "build
 > sections" perhaps?

"Elements" is appropriate in this case, since the property is applied exactly to
elements.


This suggestion needs only two values for the property, 'always' and 'avoid' in
the terms you used. It only provides for showing and hiding the elements,
though, it doesn't provide, for example, a way for the element to go from being
shaded to being fully visible.

-- 
Ian Hickson                                      )\._.,--....,'``.    fL
"meow"                                          /,   _.. \   _\  ;`._ ,.
http://index.hixie.ch/                         `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 12 July 2002 18:26:04 GMT

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