Minutes of the June PWG XHTML-Print meeting

Minutes of the June PWG XHTML-Print meeting
(Unapproved)

Location:

Hilton Portland, Portland, Oregon
June 24, 2002

Agenda:

I.	Introductions
II.	Review and Approve minutes from April 
III.	Review status of open issues and action items from minutes
    i)	CSS Attributes Proposal from Melinda and Elliot 
IV.	Review of xhtml version of the document 
V.	Discussion on Canon's request to reorganize the specification 
        see:  
           http://www.pwg.org/hypermail/xp/0036.html
           http://www.pwg.org/hypermail/xp/0038.html
           http://www.pwg.org/hypermail/xp/att-0036/01-xhtml-print-CanonDraftProposal-020529.pdf
VI.	W3C Device Independent Working Group and its effect of XHTML-Print 
        (http://www.w3.org/2002/06/w3c-di-wg-charter-20020612.html note: section5.2.5)
VII.	New Issues
    i)	Using Multiple Style Sheets
         (http://www.pwg.org/hypermail/xp/att-0040/01-One_or_more_style_sheets_can_be_used_in_a_document.doc)
VIII.	Adjourn

Minutes:

Jim Bigelow agreed to be the minute taker for the meeting.

Review of minutes from April meeting

Accepted as distributed

Review of XHTML Attributes categorization:

Melinda Grant and Elliot Bradshaw examined each of the relevant XHTML attributes and categorized them into:

• Required – a conforming printer must support an attribute marked required
• Optional – a conforming printer does not have to support such an attribute and any support is implementation dependent.
• Ignored – these attributes are not meaning full when printing.

Note: a revised version of the attribute-spread sheet was distributed the Friday before the meeting so participants had not had time to review it. A discussion of some of the attributes marked "optional" occurred with the understanding that the committee would discuss and decide how all the attributes should be handled in subsequent meetings:

Attribute	Discussion
action, cols, enctype, method, rows, tabindex, <select size>	Consideration of this attribute and others directly related to supporting the Basic Forms module showed some difficulties with printing a representation of a form. Printing a blank form or a form containing the default values is not difficult. The problem comes up when considering a use case where users would like to fill out a form and print it, as filled out, for a record or confirmation of a transaction. XHTML-Print support for this use case is not possible within the specification of XHTML-Print constructs since the data entered into the form by the user is not part of the language, rather it is a separate data stream. The entity presenting the form can avoid the problem by presenting an information page integrating the user's data and the form. Melinda Grant suggested that only minimal support for printing a blank form be mandated in the language since there is no method within the language to merge the user data and the form. Jacob Refstrup suggested that the user data and form could be transmitted to the printer in a multi-part/multiplexed data stream in a manner similar to the transmission of inline data.
Charset	The suggestion is this attribute is optional since UTF-8 handles character set specification. The manner that a conforming printer handles this attribute is implementation dependent.
Classid & codetype	The suggestion is one attribute is supported they must both be supported.
Declare	Support for this attribute is optional since low memory device any not be able to honor the intent of attribute – to store the image for later reference.
Src	Make jpeg baseline the minimum requirement
Valign	The rationale for suggesting this be optional was not available during the discussion, in its absence the suggestion is to make it required.

Review of xhtml version of the document

• Melinda Grant is leaving the committee so there is an opening for an editor for the specification.
• The question of how to keep a document change history was raised. One possibility is to add a change history to the end of the document. Jacob Refstrup suggested that a version of the wdiff tool for finding and marking differences between to html documents would be very useful now that the specification is in XHTML format.

Action Item: Jacob Refstrup will locate and make available a version of a tool to find and mark differences between two html documents.

• The question of where in the specification to put the annotated list of attributes that Melinda Grant and Elliot Bradshaw created was discussed. Suggestions for a separate appendix or placement in the conformance section (2.3.2) were put forth.

Action Item: Don Wright is to decide where in the specification the attributes will be discussed.

• Section 2.3.2, item 8. The example, "&#X007" is a character reference not an entity reference.

Action Item: Don Wright will replace the character reference with an entity reference.

• Melinda Grant asked how to keep the conformance section of the document (Section 2.3) in step with w3c specs. The discussion that followed weighted the value of a stable specification against the redundency of restating other specifications.

Action Item:

1. Do more research on how the w3c documents handle this issue.
2. Weight the pros and cons of two techniques:
   • Restate the conformance requirements in force at the time the spec is issued with changes and requirements necessary for XHTML-Print.
   • Simply refer to basic conformance requirements inherited from referenced documents and only state the exceptions, changes, and XHTML-Print requirements.

Canon's request to reorganize the specification

There were two parts to the proposal to restructure the specification:

1. The intent to specify XHTML-Print as a composition of four components: 1) a base element spec, 2) a base style spec, 3) and additional style spec, and 4) image rotation; and
2. EXIF markers in the image are not the way to indicate the orientation of the image on the page.

The discussion of how to organize the specification can be summarized as follows:

• There is no base sufficient for printing: XHTML Basic is not sufficient for printing: it lacks support for text presentation, and style. Therefore, creating a specification from the modules defined in Modularization of XHTML is clearer than using XHTML Basic as the starting point. Furthermore, CSS-Mobile is focused on presentation on a display such as a cell phone rather than a printed page, which makes it a difficult place to base a specification for pagination and printing.
• There is w3c work in progress on the modularizing CSS, but it is not available yet.
• More work needs to be done to complete the specification of the CSS properties and selectors needed for printing.

The discussion of how to specify an image's orientation can be paraphrased as follows:

• All parties would like the w3c to specify a way to state how an image is oriented on the page, rather than have the orientation within the image header.
• There is work in progress by the w3c to create a way to specify orientation but not arbitrary rotation, i.e., only rotation at 90-degree intervals. This work is specific to images and not to the CSS box layout algorithm.
• All parties would like to have rotation of images. Melinda Grant suggested support for orientation in the near future and rotation at some later date is preferable.

  Action Item: Canon will bring up the issue of image rotation with the w3c so that a w3c approved method can created and used in the XHTML-Print specification. In the interim the processing of EXIF marker will be optional.

• The interaction with EXIF markers and a not yet developed CSS property for specifying the orientation/rotation of the images was discussed. What if the EXIF marker exists and the CSS property is or is not there?

Action Item: post the issue for discussion of the PWG XP mailing list for 2 weeks.

W3C Device Independent Working Group and its effect on XHTML-Print

The mission of the W3C Device Independent Working Group is to study issues related to authoring, adaptation and presentation of Web content and applications that can be delivered effectively through different access mechanisms. The group's charter (Section 5.2.5 Printer related groups) names the PWG XHTML-Print committee as the body responsible for the definition of print markup (XHTML-Print) and printer capability descriptions.

Using Multiple Style Sheets

The link element can be used to include one or more style sheets in a document. Depending on the attributes within the link element the style sheet:

• will always be applied,
• only applied to the named media, e.g., print or screen,
• be one of a set of alternate sheets that the user can choose from, and finally,
• the preferred alternate style sheet.

The consensus is that:

1. Link elements referencing style sheets for media other than print, e.g., screen should be ignored.
2. The use of alternate style sheets is discouraged and a conforming printer's response to alternate style sheets is implementation dependent.
3. If there is a set of alternate style sheets that are not ignored by rule 1 above, and a preferred style sheet exists, the preferred sheet will be used and the remainder of the alternate sheets ignored. If multiple preferred sheets exist, the first one encountered will be used.

Action Item: Jim Bigelow will write a paragraph for the XHTML-Print specification dealing with multiple style sheets in a document.

Work on running page headers and footers and CSS level 2.1

Jacob Refstrup is attending CSS meetings and reports that:

1. The model for specifying running headers and footers is changing. The previous model allowed the side margin boxes to overlap the header and footer margin boxes so that text in the boxes could overlap. The new model is similar to a table row and will avoid overlapping area. Jacob Refstrup is the lead editor for the new proposal that will be presented at the next CSS meeting in late August.
2. Work on a CSS 2.1 specification is on-going. CSS 2.1 does not contain the @page rule since w3c candidate recommendations must be testable and @page cannot be tested at the time. Therefore, the @page rule will be moved to CSS Level 3 (AKA current work)

XSL Formatting Objects and XHTML-Print

XSL (eXtensible Stylesheet Language) is a markup language for formatting material to media such as a page. XSL contains 51 formatting objects and 231 properties for configuring the formatting objects.

Harry Lewis called for a consideration of the relationship of XSL formatting objects and XHTML-Print. The consensus was that XSL is too complex for low cost printers to implement.

Future work and directions for the CSS portion of the XHTML-Print specification

Melinda Grant called for a consideration of how to deal with the CSS material now in the XHTML-Print specification since it is not complete. The discussion evolved into a consideration of the structure of the XHTML-Print specification and ended with the proposal that the specification be broken into the following separate documents:

• CSS Print Profile – a specification defining a subset of CSS level 2 plus elements of CSS level 3 tailored to the needs and constraints of printing devices.
• XHTML Print – a specification of a subset of the XHTML 1.0 designed for printing in environments where it is not feasible or desirable to install a printer- specific driver and where some variability in the formatting of the output is acceptable.
• XHTML + CSS: A Profile for Printing – a specification referencing: XHTML Print, the CSS Print Profile, JPEG Decoder requirements, and Inline Image Data requirements.

The first two documents, CSS Print Profile and XHTML Print, could be the responsibility of the w3c. The last document, "XHTML + CSS: A Profile for Printing," would be the responsibility of the PWG.

Action Item: Jacob Refstrup will write the first draft of "CSS Print Profile." Don Wright will write drafts of the other two documents: "XHTML Print" and "XHTML + CSS: A Profile for Printing"

Conversion of the XHTML-Print DTD to an XML Schema

Work is continuing with the conversion w3c documents to an XML schema. When the conversion is complete, the DTD can also be easily converted.

Future Meetings: