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Bug 7645 - associate printable pages and less-convenient-to-print pages with link rel value "print"
Summary: associate printable pages and less-convenient-to-print pages with link rel va...
Status: CLOSED WORKSFORME
Alias: None
Product: HTML WG
Classification: Unclassified
Component: pre-LC1 HTML5 spec (editor: Ian Hickson) (show other bugs)
Version: unspecified
Hardware: All All
: P3 normal
Target Milestone: ---
Assignee: Ian 'Hixie' Hickson
QA Contact: HTML WG Bugzilla archive list
URL:
Whiteboard:
Keywords: NE
Depends on:
Blocks:
 
Reported: 2009-09-16 00:50 UTC by Nick Levinson
Modified: 2010-10-04 14:47 UTC (History)
4 users (show)

See Also:


Attachments

Description Nick Levinson 2009-09-16 00:50:12 UTC
The principal content across multiple pages is commonly also available in a single-page layout that's more convenient to print. But a search engine does not need to list both.

The existing value "alternate" is inadequate when both documents are of the same type, medium, and language, as they often are.

I propose section 6.12.3 add a value for the link element for the rel atribute
to refer to the easier-to-print page's URL. I propose the rel value be "print".

I don't know whether the rev value can be properly supported in all cases, unless multiple href attributes are allowed or will be. One possibility is that the href for rev="print" should be to the first page in a multi-page series; another is that is may be to any page in the series, as the website owner wishes.

Where the two formats are both single-page formats, e.g., where one has an artistic background and the other has a plain white background, rev would work fine.

I plan to add this to the RelExtensions wiki unless there's an objection.

Thank you.

-- 
Nick
Comment 1 Ian 'Hixie' Hickson 2009-09-29 02:06:53 UTC
What's wrong with <link rel=alternate media=print> ?
Comment 2 Nick Levinson 2009-10-04 22:39:07 UTC
> What's wrong with <link rel=alternate media=print> ?

Typically, both sets of pages are printable and also fit all other media. A difference in convenience (the usual case) is not a difference in basic ability. Therefore, media="print" and media="all" would apply to both.

If a page designer assigns a stylesheet only for "print" to the print-preferred page and another stylesheet for all other media, itemizing them all except print in the stylesheet link/s on the pages that are less convenient to print, the risk is whether some UAs that normally support printing would decline to send the less-convenient pages to the printer at all, because they're linked to a stylesheet for nonprint media only. Section 6.7.2 says, "User agents should also run the printing steps whenever the user asks for the opportunity to obtain a physical form (e.g. printed copy) . . . .", and, semantically, "should" allows a UA to not print what the link doesn't say is printable.

"Unless otherwise specified, a keyword must not be specified more than once per rel attribute." Section 6.12.3, above the table. Section 6.12.3.1 implicitly allows multiple link elements (e.g., ". . . if a document links to two other documents with the link type "alternate" . . . ."). I read the two provisions together as meaning that multiple rel alternate links are allowed on a page but only if the links are unique within the page. This bars linking from a single hreflang French page to two hreflang German pages of the same type and media.

An advanced user might know to use a keyboard's Print Screen key, but that's outside of HTML5, is often unknown to nonexpert users, and can be cumbersome to use on some pages with some displays.

Forbidding some pages from printing is not a great idea when the difference is merely one of convenience or between strong and moderate legibility, when, as if often the case, the less-suitable pages would still be functionally readable. The difference is most frequently that one consumes more paper and takes more steps to execute, e.g., as browsers don't usually accept a range of Web pages to print.

This proposed link is to point to a nonrestrictive preference suggested by the page author.
Comment 3 Ian 'Hixie' Hickson 2009-10-18 09:57:33 UTC
> Typically, both sets of pages are printable and also fit all other media. A
> difference in convenience (the usual case) is not a difference in basic
> ability. Therefore, media="print" and media="all" would apply to both.

media=print just means that the page is primarily intended for the print media, it doesn't mean other media can't be used.


> If a page designer assigns a stylesheet only for "print" to the print-preferred
> page and another stylesheet for all other media, itemizing them all except
> print in the stylesheet link/s on the pages that are less convenient to print,
> the risk is whether some UAs that normally support printing would decline to
> send the less-convenient pages to the printer at all, because they're linked to
> a stylesheet for nonprint media only.

This is not a realistic risk. No browser is going to do this.


> Section 6.7.2 says, "User agents should
> also run the printing steps whenever the user asks for the opportunity to
> obtain a physical form (e.g. printed copy) . . . .", and, semantically,
> "should" allows a UA to not print what the link doesn't say is printable.

Sure, the UA could also refuse to show media=screen pages, or in fact any pages at all. UAs aren't going to, though.


> "Unless otherwise specified, a keyword must not be specified more than once per
> rel attribute." Section 6.12.3, above the table. Section 6.12.3.1 implicitly
> allows multiple link elements (e.g., ". . . if a document links to two other
> documents with the link type "alternate" . . . ."). I read the two provisions
> together as meaning that multiple rel alternate links are allowed on a page but
> only if the links are unique within the page. This bars linking from a single
> hreflang French page to two hreflang German pages of the same type and media.

I don't understand the relevance (and it seems you are misreading the requirements — they should be read literally, not interpreted as above).


> Forbidding some pages from printing is not a great idea when the difference is
> merely one of convenience or between strong and moderate legibility, when, as
> if often the case, the less-suitable pages would still be functionally
> readable. The difference is most frequently that one consumes more paper and
> takes more steps to execute, e.g., as browsers don't usually accept a range of
> Web pages to print.
> 
> This proposed link is to point to a nonrestrictive preference suggested by the
> page author.

That's what rel=alternate media=print does.
Comment 4 Nick Levinson 2009-10-18 21:31:05 UTC
> . . . (and it seems you are misreading the requirements . . . [--]
> they should be read literally, not interpreted as above).
When the provisions apply but literalism doesn't say how, interpretation is necessary and inevitable. If one of two provisions bars multiple use and the other permits it, the two must be reconciled.

>> This bars linking from a single hreflang French page to
>> two hreflang German pages of the same type and media.
> I don't understand the relevance . . . .
The French-to-German example is to two of which one is the print-preferred and the other is the print-nonpreferred.

>> . . . semantically, "should" allows a UA to not print what the link
>> doesn't say is printable ["because they're linked to a stylesheet
>> for nonprint media only"].
> Sure, the UA could also refuse to show media=screen pages, or
> in fact any pages at all. UAs aren't going to, though.
If UAs were required (not merely expected) to comply, refusing to show any pages or those CSS-styled for screen would not be allowed.

If the spec works on point as implemented, it'll have to do, but relying on understandings of intent in bug reports instead of on explicit statements in the spec leaves too much room for UA design managers, who'll probably never trace from a spec provision to a bug discussion to find intent before programming.
Comment 5 Maciej Stachowiak 2010-03-14 14:51:23 UTC
This bug predates the HTML Working Group Decision Policy.

If you are satisfied with the resolution of this bug, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document:
  http://dev.w3.org/html5/decision-policy/decision-policy.html

This bug is now being moved to VERIFIED. Please respond within two weeks. If this bug is not closed, reopened or escalated within two weeks, it may be marked as NoReply and will no longer be considered a pending comment.
Comment 6 Nick Levinson 2010-03-28 18:43:40 UTC
I'm closing, mainly on reliance on Ian Hixie's assurance that UAs wouldn't refuse to print a page supported by a nonprint stylesheet only, even without a clear statement in HTML5 to that end.

Thank you.