RE: XP> Margins, borders, padding, and backgrounds

From: Elliott Bradshaw (Elliott.Bradshaw@Zoran.com)
Date: Thu Sep 21 2006 - 17:39:30 EDT

  • Next message: Grant, Melinda: "RE: XP> Margins, borders, padding, and backgrounds"

    Hi Melinda,

     

    This is very helpful. At first blush I'm inclined to agree with all
    your suggestions.

     

    I would like to raise 2 related issues for discussion by the group:

     

    1. When a property and its equivalent attribute are specified,
    which one wins? I don't recall seeing this anywhere, but maybe I missed
    it.

     

    2. When a printer has nonprintable margins, how should we handle
    them (assuming they exceed the applicable page/body margins)? One
    approach is to simply clip the content, but this seems to me to run
    against the spirit of "content is king". Another approach would be to
    shrink to fit so that the inside-the-margins area is shrunk slightly and
    perhaps shifted to fit inside the physically printable area. The
    algebra is a little tricky when we are also shrinking to fit a smaller
    page size, but I think this could be solved.

     

    I'm wondering what people think about these, and whether we should try
    to decide them and publish the answer somewhere. If there is interest
    in shrink-to-fit for #2, I can write up a more specific proposal.

     

    Cheers,

    Elliott

     

     

    ________________________________

    From: owner-xp@pwg.org [mailto:owner-xp@pwg.org] On Behalf Of Grant,
    Melinda
    Sent: Wednesday, September 20, 2006 4:49 PM
    To: xp@pwg.org
    Subject: XP> Margins, borders, padding, and backgrounds

     

    From HP's perspective (and I think we're not alone), the CSS
    specification is difficult to interpret with respect to how margins,
    borders, padding, and backgrounds work when applied to the <body> and
    <html> elements. Recently we have learned that the CSS3 Paged Media
    module is not clear on how the same properties used within an @page
    context should interact with the html properties.

     

    I'd like to share my new-and-improved understanding based on discussions
    within the CSS WG: ;-)

    * First, there are html attributes and there are css properties.
    In html, the body element has a bgcolor attribute, but the html element
    does not. For XHTML documents, the UA (printer) must convert the body
    bgcolor attribute into an equivalent printer style rule:
            So <body bgcolor="red"> gets converted into the printer
    stylesheet rule: body {background-color: red}. (This gets a bit more
    complicated for HTML documents, but we don't need to go there.) This
    printer stylesheet rule will be overridden by an author stylesheet rule,
    should one exist. See
    http://www.w3.org/Style/Group/css2-src/cascade.html#q13.
    * The body element is no different when it comes to CSS styling
    from any other element. Backgrounds, margins etc behave just as they do
    for a div, for example.
    * The html element is the root element. It can also be selected
    with ':root'. It is special, in that a background is applied to the
    margins as well as the content area. This is because it 'paints the
    canvas', which is infinite. The only way in XHTML to put a background
    in the html margin area and/or the body margin area is to use a
    background on the html element. (See
    http://www.w3.org/TR/CSS21/colors.html#q2.)
    * The attached file, 'margin-both.xhtml' when opened with Firefox,
    provides an example of how html and body edgings should be rendered.

    There are still some open questions about how @page properties work. I
    am hoping to publish a new version within the next week or so that will
    resolve questions such as the following: [My proposed answers are in
    brackets.]

    * Is a font property set within an @page rule applied to the page
    content area (unless overridden by properties set on elements rendered
    on the page), or just to the contents of the page margin boxes?
    [Proposed Answer: Just to the margin boxes.]
    * Do the html and page margins collapse? [no]
    * Are html and body borders closed at the bottom of each page, or
    just at the end of the document? [Just at the end of the document]
    * Does a background property set within an @page rule get applied
    to the page margins? [Yes] To the page area unless obscured by html,
    body, or other backgrounds? [????, under discussion]
    * On the last page of a document, do the html and body properties
    terminate immediately after the last content, or at the bottom of the
    page (e.g., do the html and body margins get drawn right below the last
    paragraph, or at the bottom of the page? [Immediately after content.]
    * Similarly, on the last page, do the page bg, border, etc. extend
    to the bottom of the page, or terminate after the last content? [bottom
    of the page]
    * Others?

    Best regards,

     

    Melinda

      _____

    HP - Melinda Grant
    Connectivity Standards
    Consumer Printing and Imaging
    +1 (541) 582-3681
    melinda.grant@hp.com
      _____

     



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