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XHTML-Print is member of the family of XHTML languages defined by the Modularization of XHTML [ XHTMLMOD ]. It is designed to be appropriate for printing from mobile devices to low-cost printers that might not have a full-page buffer and that generally print from top-to-bottom and left-to-right with the paper in a portrait orientation. XHTML-Print is also targeted at 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.
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
All sections of this document are normative unless noted as informative.
This document contains the XHTML™-Print W3C Candidate Recommendation of 20 January 2004 which has incorporated the disposition of Last Call comments .
This specification is based, in large part, on a work by the same name, XHTML™-Print [ XHTMLPRINT ] from the Printer Working Group (PWG), a program of the IEEE Industry Standard and Technology Organization.
In order to exit the Candidate Recommendation phase, the following criteria must be satisfied:
A test suite for this specification will be created during the CR period. Detailed implementation requirements and the invitation for participation in the implementation report will be provided in the preliminary implementation report . Implementers are encouraged to provide feedback by 20 July 2004.
Comments are to be sent to www-html-editor@w3.org ( archive ). It is inappropriate to send discussion email to this address. Public discussion may take place on www-html@w3.org ( archive ).
This document has been produced by the W3C HTML Working Group ( Members only ) as part of the W3C HTML Activity . The goals of the HTML Working Group are discussed in the HTML Working Group charter . Patent disclosures relevant to this specification can be found on the Working Group's patent disclosure page .
Publication as a Candidate Recommendation does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
img
and
object
Elements
All sections of this document are normative unless noted as informative.
This section is informative.
This document specifies a simple XHTML based data stream suitable for printing as well as display. It is based on XHTML Basic [ XHTMLBASIC ] with the addition of Cascading Style Sheets (CSS) from CSS Print Profile [ CSSPP ]. Its targeted usage is 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. Throughout this document this data stream is called "XHTML-Print."
XHTML-Print is designed to be appropriate for low-cost printers that might not have a full-page buffer and that generally print from top-to-bottom and left-to-right with the paper in a portrait orientation. For other printers (i.e., those that print in another direction or orientation) a full-page buffer could be needed.
XHTML-Print is not appropriate when strict layout consistency and repeatability across printers are needed. The design objective of XHTML-Print is to provide a relatively simple, broadly supportable page description format where content preservation and reproduction are the goal, i.e. "Content is King." Traditional printer page description formats such as PostScript or PCL are more suitable when strict layout control is needed. XHTML-Print does not utilize bi-directional communications with the printer either for capabilities or status inquiries.
This document creates a set of conformance criteria for XHTML-Print. It references style sheet constructs drawn from CSS2 [ CSS2 ] and proposed for CSS3 Paged Media [ PAGEMEDIA ] as defined in the CSS Print Profile [ CSSPP ] to provide a strong basis for rich printing results without a detailed understanding of each individual printer's characteristics.
It also defines an extension set that provides stronger layout control for the printing of mixed text and images, tables and image collections.
The document type definition for XHTML-Print is implemented based on the XHTML modules defined in Modularization of XHTML [ XHTMLMOD ].
The keywords " MUST ", " SHALL ", " MUST NOT ", " SHALL NOT ", " REQUIRED ", " SHOULD ", " SHOULD NOT ", " RECOMMENDED ", " MAY ", and " OPTIONAL " when used in this document are to be interpreted as described in RFC 2119 [ RFC2119 ]. However, for readability, these words might not appear in all uppercase letters in this specification.
This section explains why certain HTML features are not part of XHTML-Print and any special circumstances concerning a module and printing.
Scripts,
as
programs
that
are
executed
in
conjunction
with
a
document,
are
not
relevant
to
the
printed
page.
However,
documents
can
provide
information
as
an
alternative
to
a
script.
Therefore,
the
script
module
is
part
of
XHTML-Print
since
the
content
of
the
script
element
MUST
be
treated
as
if
its
display
property
were
set
to
the
value
"none"
and
the
content
of
the
noscript
element
printed.
Events are not applicable to static, printed versions of a document. Therefore, the Intrinsic Events module is not part of XHTML-Print.
Many simple printers cannot print a wider variety of fonts than generic serif, sans serif and monospace. It is RECOMMENDED that style sheets be used to create a presentation that is appropriate for a particular category of printer. How printers are categorized, what those categories are, how a printer identifies itself as a member of a category, and how style sheets are selectively applied based on category, is outside the scope of this document.
The Presentation module ([ XHTMLMOD ], section 5.4.1) is supported to allow very simple printers to support basic font variants and rules without the need to implement support for CSS as REQUIRED by CSS Print Profile [ CSSPP ]. However, printers SHOULD provide support for CSS within the limits of their device.
Basic XHTML forms ([ XHTMLMOD ], section 5.5.1) are supported. Content developers SHOULD keep in mind that users might not be able to input many characters from some devices ( e.g. from a mobile phone). Furthermore, developers are cautioned that a printer prints a static version of a form, and the visual appearance of a form depends heavily on the implementation.
Basic XHTML tables ([ XHTMLMOD ], section 5.6.1) are supported, but tables can be difficult to format on very low resource devices. Furthermore, content developers are cautioned that in the Basic Tables Module, nesting of tables is prohibited.
Frames are not supported. Frames depend on a screen interface and therefore are not applicable to printers.
XHTML-Print is a member of the family of XHTML languages defined by Modularization of XHTML [ XHTMLMOD ]. Therefore, the elements and attributes in the modules that make up XHTML-Print are all valid constructs of the language. However, not all the attributes are applicable to a rendering of an XHTML-Print document in a printed media, especially those that are integral to a dynamic display of the document in a browser and the submission of a form. Furthermore, special attention is given to simple printers and some attributes are deemed too complex for a such a printer to render. These attributes are treated as discretionary in that a conforming printer is not REQUIRED to support them, but if a printer wishes to provide that support, there are requirements stated for consistency in the implementation of extensions.
The W3C architectural specification Character Model for the World Wide Web 1.0 [ CHARMOD ] gives the RECOMMENDED representation of characters in XHTML-Print. Authors of XHTML-Print producing applications SHOULD be aware that low cost printers might be limited in both processing power and memory and therefore, that fully-normalized ([ CHARMOD ], 4.2.3 ) utf-8 encoded documents could print more quickly than documents in other forms and encodings.
A conforming XHTML-Print document is a document that requires only the facilities described as mandatory in this specification. Such a document SHALL meet all of the following criteria:
html
.
http://www.w3.org/1999/xhtml
.
The MIME type used to refer to a conforming XHTML-Print document SHALL be either "application/xhtml+xml" or "application/vnd.pwg-xhtml-print+xml". However, the MIME Type "application/vnd.pwg-xhtml-print+xml" is deprecated in favor of "application/xhtml+xml". Required support for the MIME Type "application/vnd.pwg-xhtml-print+xml" MAY be removed from future releases of this specification. An OPTIONAL "charset" parameter MAY be provided with the MIME type. Invalid values MUST be ignored and the result be as if the value were "utf-8". Usage of the OPTIONAL "charset" parameter is as described in section 3.2 of RFC3023 - XML Media Types [ RFC3023 ].
A printer MUST conform to the XHTML Family User Agent Conformance section of the Modularization of XHTML specification ([ XHTMLMOD ], section 3.5) with the following exceptions and additions:
height
and
width
attributes
by
optionally
drawing
a
box
around
this
space
of
the
size
specified
for
the
image.
height
and
width
attributes
are
absent
and
no
alternate
content
is
provided,
the
image
MAY
be
omitted
and
no
space
reserved.
height
and
width
attributes
were
omitted,
the
printer
MAY
choose
to
omit
the
image
from
the
page.
xml:lang
attribute
are
not
REQUIRED
to
adhere
to
the
rules
for
language
specific
white
space
handling.
To further support print applications requiring more exacting page layout ( e.g., photo album pages), the style sheet properties of the Enhanced Layout Extension of the CSS Print Profile ([ CSSPP ] section 2.1) and image processing ( Appendix A.3 ) SHALL be supported in an OPTIONAL , discoverable (via some means outside the scope of this document) Enhanced Layout Extension.
The following is an informative example using absolute positioning with image data:
The XHTML-Print document type is defined as a set of XHTML modules. All XHTML modules are defined in the Modularization of XHTML specification [ XHTMLMOD ].
XHTML-Print consists of the following XHTML modules:
body,
head,
html,
title
abbr,
acronym,
address,
blockquote,
br,
cite,
code,
dfn,
div,
em,
h1,
h2,
h3,
h4,
h5,
h6,
kbd,
p,
pre,
q,
samp,
span,
strong,
var
a
dl,
dt,
dd,
ol,
ul,
li
b,
big,
hr,
i,
small,
sub,
sup,
tt
form,
input,
label,
select,
option,
textarea
caption,
table,
td,
th,
tr
img
object,
param
meta
noscript
,
script
style
style
attribute
link
base
(*)
=
This
module
is
a
REQUIRED
XHTML
Host
Language
module.
(**)
=
These
modules
are
not
a
part
of
XHTML
Basic
but
are
REQUIRED
for
XHTML-Print.
An XML 1.0 DTD is available in Appendix C.
Some of the attributes defined in the Modularization of XHTML [ XHTMLMOD ] are not applicable to the printed page or are not relevant due to the exclusion of their module from XHTML-Print. Other attributes have equivalent CSS properties that when present take precedence over the attribute. Other attributes are not REQUIRED but if supported by a printer, support SHOULD be provided in the RECOMMENDED manner.
Each attribute in the following sections is annotated to indicate the processing REQUIRED of a conforming printer:
Key | Description |
---|---|
MUST | Support is mandatory; a conforming printer MUST implement this attribute |
SHOULD | The attribute is concerned with functionality that SHOULD be implemented but might be beyond the capability of a conforming printer. For example, a monochrome printer can only render a gray scale equivalent of color images. A conforming printer MUST NOT treat this attribute as an error. |
MAY | The attribute's functionality is considered too complex, either in processing or memory requirements, for a conforming printer. For example, determining vertical alignment within the cells of a row that spans multiple pages could exceed a low cost printer's available memory, therefore, it is not REQUIRED of a conforming printer. A conforming printer MUST NOT treat this attribute as an error. |
N/A |
The
attribute
does
Not
Apply
to
the
printed
page;
a
conforming
printer
MAY
ignore
this
attribute
for
one
of
the
following
reasons,
but
MUST
NOT
treat
it
as
an
error:
|
The Modularization of XHTML ([ XHTMLMOD ], section 5.1) contains a set of attribute collections for ease of presentation. This specification continues this practice with the same conditions, that is, that the collections below are informative and their contents normative.
Collection Name | Attributes in Collection | REQUIRED Processing |
---|---|---|
Core | class ( NMTOKENS † ) | MUST |
Core | id ( ID † ) | MUST |
Core | title ( CDATA † ) | N/A |
I18N | xml:lang ( NMTOKEN † ) | MAY |
Style | style ( CDATA † ) | SHOULD |
Common | Core + I18N + Style | See Collections |
Table Note:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
Note
that
the
title
attribute
of
the
Core
collection
is
not
applicable
to
the
printed
page
since
there
is
no
place
to
display
such
supplementary
information.
A
printer
MAY
support
special
processing
based
on
the
natural
language
of
the
document,
such
as
the
use
of
guillemets
for
quotation
marks
in
French
text.
If
a
printer
implements
processing
based
on
the
natural
language
of
the
document,
that
processing
SHALL
be
controlled
by
the
xml:lang
attribute.
A printer SHOULD support CSS style sheets, as noted in section 1.3.2 Presentation , within the limits of its capabilities.
Elements | Attributes | REQUIRED Processing |
---|---|---|
body | Common | See Collection |
head | I18N , | See Collection |
head | profile ( URI † ) | MAY |
html | I18N , | See Collection |
html | version ( CDATA † ), | N/A |
html | xmlns ( URI † = "http://www.w3.org/1999/xhtml") | MUST |
title | I18N | See Collection |
Table Note:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
If
a
printer
implements
support
for
meta
data
then
it
MUST
support
the
profile
attribute
of
the
head
element.
The
version
attribute
is
not
applicable
for
printing
since
it
was
deprecated
in
the
HTML
4.01
Specification
[
HTML4
]
in
favor
of
version
information
within
the
DTD.
A
printer
can
ignore
the
content
of
the
title
element
since
it
is
not
part
of
the
document's
body.
Elements | Attributes | REQUIRED Processing |
---|---|---|
abbr, acronym, address | Common | See Collection |
blockquote | Common , | See Collection |
blockquote | cite ( URI † ) | N/A |
br | Core | See Collection |
cite, code, dfn, div, em, h1, h2, h3, h4, h5, h6, kbd, p | Common | See Collection |
pre | Common , | See Collection |
pre | xml:space="preserve" | MUST |
q | Common , | See Collection |
q | cite ( URI † ) | N/A |
samp, span, strong, var | Common | See Collection |
Table Note:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
Element | Attributes | REQUIRED Processing |
---|---|---|
a | Common , | See Collection |
a | accesskey ( Character † ), | N/A |
a | charset ( Charset † ), | N/A |
a | href ( URI † ), | N/A |
a | hreflang ( LanguageCode † ), | N/A |
a | rel ( LinkTypes † ), | N/A |
a | rev ( LinkTypes † ), | N/A |
a | tabindex ( Number † ), | N/A |
a | type ( ContentType † ) | N/A |
Table Note:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
Elements | Attributes | REQUIRED Processing |
---|---|---|
dl, dt, dd, ol, ul, li | Common | See Collection |
Elements | Attributes | REQUIRED Processing |
---|---|---|
b, big, hr, i, small, sub, sup, tt | Common | See Collection |
Elements | Attributes | REQUIRED Processing |
---|---|---|
form | Common , | See Collection |
form | action * ( URI † ), | N/A |
form | method ("get" ** | "post"), | N/A |
form | enctype ( ContentType † ) | N/A |
input | Common , | See Collection |
input | accesskey ( Character † ), | N/A |
input | checked ("checked"), | MUST |
input | maxlength ( Number † ), | N/A |
input | name ( CDATA † ), | N/A |
input | size ( Number † ), | MUST |
input | src ( URI † ), | N/A |
input | tabindex ( Number † ), | N/A |
input | type("text" ** ) | MUST |
input | type("password" ) | MUST |
input | type("checkbox" ) | MUST |
input | type("radio" ) | MUST |
input | type("submit") | MUST |
input | type("reset" ) | MUST |
input | type("hidden" ) | MUST |
input | value ( CDATA † ) | MUST |
label | Common , | See Collection |
label | accesskey ( Character † ), | N/A |
label | for ( IDREF † ) | N/A |
select | Common , | See Collection |
select | multiple ("multiple"), | N/A |
select | name ( CDATA † ), | N/A |
select | size ( Number † ), | MUST |
select | tabindex ( Number † ) | N/A |
option | Common , | See Collection |
option | selected ("selected"), | MUST |
option | value ( CDATA † ) | MUST |
textarea | Common , | See Collection |
textarea | accesskey ( Character † ), | N/A |
textarea | cols * ( Number † ), | MUST |
textarea | name ( CDATA † ), | N/A |
textarea | rows * ( Number † ), | MUST |
textarea | tabindex ( Number † ) | N/A |
Table Notes:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
* The attribute MUST be present.
** The value is the default.
The
src
attribute
of
the
input
element
is
not
supported
since
the
image
type
is
not
part
of
basic
forms.
The
hidden
type
for
the
input
element
MUST
be
supported
even
though
nothing
is
printed,
so
that
a
printer
can
correctly
recognize
and
ignore
the
element.
Elements | Attributes | REQUIRED Processing |
---|---|---|
caption | Common | See Collection |
table | Common, | See Collection |
table | summary ( Text † ) | N/A |
td, th | Common , | See Collection |
td, th | abbr ( Text † ), | MAY |
td, th | align ("left" | "center" | "right"), | MUST |
td, th | axis ( CDATA † ), | N/A |
td, th | colspan ( Number † ), | MUST |
td, th | headers ( IDREFS † ), | N/A |
td, th | rowspan ( Number † ), | MUST |
td, th | scope ("row" | "col"), | N/A |
td, th | valign ("top" | "middle" | "bottom") | MUST |
tr | Common , | See Collection |
tr | align ("left" | "center" | "right"), | MUST |
tr | valign ("top" | "middle" | "bottom") | MUST |
Table Note:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
If
a
printer
implements
a
feature
to
truncate
the
contents
of
a
cell
because
of
space
constraints,
it
MUST
support
the
abbr
attribute
and
print
the
value
of
the
abbr
attribute
(if
present)
instead
of
the
cell's
content.
A
printer
MUST
support
the
values
left
,
right
,
and
center
for
the
align
attribute
of
the
td
,
th
,
and
tr
elements,
other
values
are
OPTIONAL
.
If
the
align
attribute
is
missing
or
has
an
unsupported
value
a
printer
MUST
act
as
if
the
align
attribute
has
the
value
left
.
A
printer
MUST
support
the
values
top
,
middle
,
and
bottom
for
the
valign
attribute
of
the
td
,
th
,
and
tr
elements,
other
values
are
OPTIONAL
.
If
the
valign
attribute
is
missing
or
has
unrecognized
value,
a
printer
SHOULD
act
as
if
the
valign
attribute
has
the
value
middle
.
Vertical
alignment
is
undefined
across
page
boundaries.
Elements | Attributes | REQUIRED Processing |
---|---|---|
img | Common , | See Collection |
img | alt * ( Text † ), | MUST |
img | height ( Length † ), | MUST |
img | longdesc ( URI † ), | N/A |
img | src * ( URI † ), | MUST |
img | width ( Length † ) | MUST |
Table Notes:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
* The attribute MUST be present.
Printers MUST support the cid [RFC2392] and http [RFC2616] schemes of a URI [RFC2396] . Support for other schemes is OPTIONAL .
Conforming
documents
SHOULD
specify
the
width
and
height
of
the
image
using
the
width
and
height
attributes,
since
a
printer
MAY
ignore
images
that
are
missing
these
attributes.
(
2.3.1
Formatting/Rendering
Rules
).
Elements | Attributes | REQUIRED Processing |
---|---|---|
object | Common , | See Collections |
object | archive ( URIs † ), | N/A |
object | classid ( URI † ), | N/A |
object | codebase ( URI † ), | MUST |
object | codetype ( ContentType † ), | N/A |
object | data ( URI † ), | MUST |
object | declare ("declare"), | MAY |
object | height ( Length † ), | MUST |
object | name ( CDATA † ), | N/A |
object | standby ( Text † ), | N/A |
object | tabindex ( Number † ), | N/A |
object | type ("image/jpeg"), | MUST |
object | width ( Length † ) | MUST |
param | id ( ID † ), | N/A |
param | name * ( CDATA † ), | N/A |
param | type ( ContentType † ), | N/A |
param | value ( CDATA † ), | N/A |
param | valuetype ("data" ** | "ref" | "object") | N/A |
Table Notes:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
* The attribute MUST be present.
** The value is the default.
Printers MUST support the cid [RFC2392] and http [RFC2616] schemes of a URI [RFC2396] . Support for other schemes is OPTIONAL .
A
printer
MUST
support
resources
of
type
"image/jpeg."
A
printer
MAY
support
other
types
of
image
formats
and
therefore
other
values
of
the
type
attribute.
A
printer
MUST
process
the
content
of
the
object
element
when
it
does
not
recognize
or
support
the
object
type
referenced
by
the
value
of
the
type
attribute.
Conforming
documents
SHOULD
specify
the
width
and
height
of
the
image
using
the
width
and
height
attributes,
since
some
printers
MAY
ignore
such
images.
(
2.3.1
Formatting/Rendering
Rules
).
The
param
element's
purpose
is
to
pass
data
to
an
application
specified
in
the
enclosing
object
element.
Since
only
images,
which
do
not
need
initialization,
are
supported
in
the
object
element,
the
param
element
can
be
completely
ignored.
Elements | Attributes | REQUIRED Processing |
---|---|---|
meta | I18N , | See Collection |
meta | content * ( CDATA † ), | N/A |
meta | http-equiv ( NMTOKEN † ), | N/A |
meta | name ( NMTOKEN † ), | N/A |
meta | scheme ( CDATA † ) | N/A |
Table Notes:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
* The attribute MUST be present.
A printer MAY implement support for this element and provide implementation specific processing of the meta-information. However, guidelines and/or recommendations for processing a document's meta-information are beyond the scope of this document.
Elements | Attributes | REQUIRED Processing |
---|---|---|
noscript | Common , | See Collections |
script | charset ( Charset ), | N/A |
script | defer ("defer"), | N/A |
script | src( URI ) , | N/A |
script | type ( ContentType ), | N/A |
script | scheme ( CDATA ) | N/A |
Scripts,
as
programs
that
are
executed
in
conjunction
with
a
document,
are
not
relevant
to
the
printed
page
and
SHOULD
NOT
be
printed.
The
noscript
element
contains
alternate
content
that
MUST
be
printed
in
place
of
the
content
of
the
script
element.
Elements | Attributes | REQUIRED Processing |
---|---|---|
style | I18N , | See Collection |
style | media ( MediaDesc † ), | SHOULD |
style | title ( Text † ), | N/A |
style | type * ("type/css"), | SHOULD |
style | xml:space="preserve" | SHOULD |
Table Notes:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
* The attribute MUST be present.
A
printer
MUST
read
and
process
the
content
of
style
elements
where
the
media
attribute
has
the
value
print
or
all
.
A
printer
MAY
read
and
process
the
content
of
style
elements
where
the
media
attribute
has
the
value
projection
.
A
printer
SHOULD
ignore
the
content
of
style
elements
where
the
media
attribute
has
any
other
value.
The
absence
of
the
media
attribute
MUST
be
treated
as
if
the
media
attribute
had
the
value
all
.
A
printer
MUST
read
and
process
the
content
of
style
elements
where
the
value
of
the
type
attribute
is
"text/css,"
all
other
values
MUST
cause
the
content
to
be
ignored.
Style
elements
without
a
type
attribute
will
be
treated
in
an
implementation
dependent
manner.
This module adds the style attribute to the Common attribute collection (section 3.1).
Elements | Attributes | REQUIRED Processing |
---|---|---|
link | Common , | See Collection |
link | charset ( Charset † ), | MUST |
link | href ( URI † ), | MUST |
link | hreflang ( LanguageCode † ), | MAY |
link | media ( MediaDesc † ), | MUST |
link | rel ("stylesheet"), | MUST |
link | rev ( LinkTypes † ), | N/A |
link | type ("text/css") | MUST |
Table Note:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4.3 )
Printers MUST support the cid [RFC2392] and http [RFC2616] schemes of a URI [RFC2396] . Support for other schemes is OPTIONAL .
If
the
printer
implements
processing
based
on
the
natural
language
of
the
document,
then
the
hreflang
attribute
MUST
be
supported.
A
printer
MUST
read
and
process
the
content
of
external
style
sheets
where
the
media
attribute
has
the
value
print
or
all
.
A
printer
MAY
read
and
process
the
content
of
external
style
sheets
where
the
media
attribute
has
the
value
projection
.
A
printer
SHOULD
ignore
the
content
of
external
style
sheets
where
the
media
attribute
has
any
other
value.
The
absence
of
the
media
attribute
MUST
be
treat
as
if
the
media
attribute
had
the
value
all
.
A
printer
SHOULD
support
the
value
stylesheet
for
the
rel
attribute
along
with
the
value
"text/css"
for
the
type
attribute,
all
other
values
are
OPTIONAL
.
Elements | Attributes | REQUIRED Processing |
---|---|---|
base | href * ( URI † ) | MUST |
Table Notes:
† See Modularization of XHTML ( [ XHTMLMOD ], section 4. 3
* The attribute MUST be present.
Printers MUST support the cid [RFC2392] and http [RFC2616] schemes of a URI [RFC2396] . Support for other schemes is OPTIONAL .
XHTML-Print is in the family of XHTML document types, since it is created by combining XHTML modules. The character entities that are part of XHTML-Print are, therefore, defined in XHTML Character Entities ([ XHTMLMOD ], Section F.1).
XHTML-Print inherits all the structure, encoding and other basic infrastructure specified by XHTML 1.0 [ XHTML1 ]. The following sections describe and clarify the application and usage restrictions of XHTML-Print.
img
and
object
Elements
Because
many
printers
create
the
page
in
a
serial
manner
from
top
to
bottom,
it
is
important
for
the
printer
to
know
the
size
of
images
before
retrieving
the
image
data
itself.
This
information
is
then
used
to
create
portions
of
the
page
layout.
Therefore,
the
sender
SHOULD
include
the
height
and
width
attributes
within
the
img
or
the
object
element.
Printers
MAY
omit
from
the
page
images
that
do
not
include
height
and
width
attributes
(see
item
2,
Images
,
of
section
2.3.1
).
These
attributes
MAY
be
expressed
as
pixels
or
percentages
within
the
img
or
the
object
element.
Percentages
are
relative
to
the
parent
element
and
not
the
page
width
or
printable
area.
This document specifies only one mandatory image format: baseline JPEG as defined in JPEG File Interchange Format [ JPEG ]. See Appendix A for a description of JPEG decoder requirements. Printers are not REQUIRED to support:
within the JFIF (JPEG File Interchange Format) and EXIF (Exchangeable Image File Format) files.
Conforming
XHTML-Print
printers
SHALL
support
both
in-line
and
referenced
style
sheets
within
the
style
element
or
link
element
in
the
head
element
of
a
document.
Conforming
XHTML-Print
printers
SHALL
also
support
the
style
attribute
(i.e.
in-line
style)
when
used
within
other
elements
as
defined
by
XHTML
1.1
[
XHTML1.1
].
Normal
cascading
rules
apply.
In traditional Web-based applications of XHTML, image data is contained in a separate file on a Web server that the user agent retrieves.
However, there are circumstances where it is desirable to include the image data along with the rest of the print data. For example, some low cost, resource constrained clients might want to include images in their print output but cannot afford to include a server. Furthermore, some printers could require that all the print data be encapsulated in a single file for transportability, avoiding firewall issues, etc. Therefore, conforming XHTML-Print printers MUST support two document formats: a format that contains both a document and its referenced image data and the traditional format that contains only the document.
[Informative] Furthermore, both formats must be supported since there is no guaranteed mechanism for the printer to advertise the formats it supports. Lacking the ability to determine a printer's support for one or both formats a sending application MUST be able to depend on support for both formats so that it can chose the format that is best for its circumstances.
See Appendix B for discussion of the method that SHALL be used to collect both XHTML-Print and associated image data into a single file or data stream.
Low-cost printers today often have very little memory into which page data can be stored before being printed. As such, they may build and print the page in swaths on the fly from the top of the page to the bottom. To enable the use of XHTML-Print in these low cost printers, some restrictions on the order of images contained in the XHTML-Print data stream must be added.
<img
src="http://example.com/example.jpg">
,
or
by
means
of
a
data
interleaving
scheme
such
as
described
in
B.2.1
Interleaving
Images
.
(See
Appendix
B)
.
This
allows
the
printer
to
get
chunks
of
the
image,
as
it
needs
it,
as
it
prints
down
the
page.
Included
image
data,
as
discussed
in
Appendix
B.3
,
is
discouraged.
An HTML form is a dynamic entity when the document is displayed in a browser: data can be entered into text fields, buttons can be pushed, selections made, and options checked. None of this dynamic activity can be rendered on a printed page. However, a printed page can permanently record a particular state of the form. For example, users might wish to print forms that record products ordered or payments made.
The following discussion illustrates the activity involved when interacting with and printing forms. Please refer to Sequence Diagram 1
Sequence
Diagram
1.
Forms
Usage
Steps:
Detailed discussion of Steps:
Here is an example presentation of the above form as the user would see it:
This section is informative.
This specification was prepared by the W3C HTML Working Group. The participants at the time of publication were:
List will be inserted when this document becomes a Recommendation.
This specification is based on the specification of the same name, XHTML™-Print [ XHTMLPRINT ], from the Printer Working Group , a program of and through the IEEE Industry Standards and Technology Organization, Inc., and the editor wishes to express his gratitude to all of those who contributed to it.
This appendix describes RECOMMENDED behaviors for JPEG decoders in XHTML-Print devices. Behaviors for both minimal printers and enhanced layout printers are described. Many of the behaviors described in this document follow directly from language already present in the relevant JPEG standards, but are repeated here to emphasize their importance.
The decoder behaviors described in this document are intended to minimize implementation complexity, while retaining maximum compatibility with existing JPEG files. In particular, these recommendations seek to ensure compatibility with both EXIF (Exchangeable Image File Format) and baseline JFIF (JPEG File Interchange Format) i.e., the subset of JFIF files that use only baseline JPEG processes. Support for JPEG streams using non-baseline processes, such as arithmetic coding or progressive coding, is not mandated for XHTML-Print compliance.
This section describes behaviors of JPEG decoders for minimal XHTML-Print implementations.
A JPEG decoder for an XHTML-Print printer SHALL support all baseline JPEG processes as defined in [ CCITT ], except for 2- and 4-component images. These processes include grayscale and 3-component images, 8-bit/component sample depth, Huffman entropy coding, 444, 422, 411, and 400 subsampling modes, and sequential (i.e. non-progressive) scan.
Baseline decoders MAY ignore application-specific markers, such as the JFIF APP0 marker and the EXIF APP1/APP2 markers. This will cause all images to print in an un-rotated orientation, with image size as specified in the JPEG SOF marker if not overridden by XHTML-Print mark-up. A JPEG decoder for a minimal printer SHALL NOT fail as a consequence of encountering an unsupported APPx marker (i.e. all such markers SHALL be correctly parsed, even if they are ignored).
This section describes a RECOMMENDED color management approach for minimal XHTML-Print printers.
Sample values in a grayscale (single-component) JPEG image SHALL be converted to the sRGB color space by setting
R out = G out = B out = Gray in
Sample values in 3-component JPEG images SHALL be interpreted as YCbCr samples, as would be obtained by applying the matrices described in ITU BT.601 [ BT601.5 ] to sRGB input data.
This section describes behaviors of JPEG decoders for XHTML-Print devices that support the XHTML-Print Enhanced Layout Extension, an OPTIONAL feature block. The behaviors described below SHOULD be interpreted as "in addition to" those described in XHTML-Print Document Type and Printer Conformance (the requirements for minimal XHTML-Print devices).
A JPEG decoder for an XHTML-Print implementation which supports the Enhanced Layout Extension MAY decode the TIFF IFDs embedded in the EXIF APP1 and APP2 markers, as described in Section 2.6.4 of [ JEIDA ]. The following IFDs MAY be supported. However, any future XHTML elements or CSS properties affecting image orientation SHALL take precedence over these IFDs.
Tag Name | Field Name | Description |
Orientation of Image | Orientation | Sets image orientation in 90-degree increments, and enables transposition. |
The intent of this appendix is to describe the method for including XHTML-Print and associated image data in a single data stream or file. Support for Image Data is REQUIRED . (See Image Data .)
In addition to images, if separate style sheets are to be interleaved with the XHTML-Print data, the same method SHALL be used.
This section includes by reference the entirety of RFC3391 - The MIME Application/Vnd.pwg-multiplexed Content-type , Robert Herriot [ MIMEMPX ]. All printers MUST support image data using RFC3391[ MIMEMPX] .
Producers and consumers of Application/Vnd.pwg-multiplexed entities (compound documents), as defined in [ MIMEMPX ], SHOULD consider each component image message of the compound document as having one and only one reference. The producer of the compound document MUST assume that the consumer of the compound document has limited memory and therefore include a unique image message for each image reference found in the root document. If a ContentID is present in the header of an image message, that ContentID MUST be unique. If a Content-Location is present in the header of an image message, that Content-Location is REQUIRED to be unique except for the special case where a repeated reference to the same image URL causes several messages containing the same image data to be present in the compound document. Consumers MAY release the message data associated with an image reference as the image is rendered, because the Consumer can be confident that another reference to the same image will be accompanied by another message containing the image data. Consumers MAY also substitute image data for a message with a given Content-Location header value with image data from other messages with the same Content-Location header value because Consumers can be confident that messages with identical Content-Location values do in fact contain identical data.
URL references in the root document of the multiplexed document MUST be matched to Content-Location and/or Content-ID fields of the referenced message object according to the rules given by RFC2557 - MIME Encapsulation of Aggregate Documents, such as HTML (MHTML) [ RFC2557 ]. An exception to the rules occurs when a reference is made to a message object named with a Content-Location [ RFC2557 ]. In that special case, multiple instances of that message are REQUIRED in the compound document.
This section is informative.
RFC3391[ MIMEMPX ] only says that an image should be placed close to its reference in a compound document. However, if an image is placed directly after its reference, the information in the image header is available, when needed, for determining the size of the image's box, where an image header is the data from the beginning of the image up to and including the start of scan marker. Furthermore, the printer will immediately know if the image is present or if its alternate content has to be printed. On the other hand, when several images will be placed on a page, some low-cost printers might not have enough memory to hold the images in memory while rendering the page. One possible solution to this dilemma is to break each image into chunks, and to place each image's header in its own chunk near the image's reference. The remainder of the chunks for each image are placed later in the compound document and could be interleaved to further reduce the memory needed to store the images while printing.
This section is informative.
An
alternative
method
to
include
image
data
in
XHTML-Print
is
via
the
data
url
scheme
[
RFC2392
].
Because
this
method
normally
encodes
the
binary
image
data
using
base64
encoding,
a
significant
increase
in
the
size
of
the
data
transmitted
will
be
experienced.
This
should
be
avoided
over
low
speed
connections.
Printers
supporting
included
data
can
support
base64
encoding
using
the
img
or
object
element.
This method could be useful for very simple clients that cannot afford a server for image downloading or for some reason cannot utilize the Application/Vnd.pwg-multiplexed MIME type [ MIMEMPX ]; however, it is not suggested for general use especially if the size of the printer's buffer is unknown.
This section contains the pieces of the XHTML-Print DTD that are unique to XHTML-Print. The remaining entities and modules are as specified in reference [ XHTMLMOD ].
The following SHOULD be used from Modularization of XHTML [ XHTMLMOD ]:
Available for download at xhtml-print10.dtd .
<!-- ....................................................................... --> <!-- XHTML-Print 1.0 DTD ................................................... --> <!-- file: xhtml-print10.dtd --> <!-- XHTML-Print 1.0 DTD This is XHTML-Print 1.0, a variant of XHTML Basic for printing. Copyright 1998-2003 World Wide Web Consortium (Massachusetts Institute of Technology, European Research Consortium for Informatics and Mathematics, Keio University). All Rights Reserved. Permission to use, copy, modify and distribute the XHTML-Print DTD and its accompanying documentation for any purpose and without fee is hereby granted in perpetuity, provided that the above copyright notice and this paragraph appear in all copies. The copyright holders make no representation about the suitability of the DTD for any purpose. It is provided "as is" without expressed or implied warranty. Primary Author: Jun Fujisawa <fujisawa.jun@canon.co.jp> Editors: Jim Bigelow <jim.bigelow@hp.com>, Shane McCarron <shane@aptest.com>, Masayasu Ishikawa <mimasa@w3.org> Revision: $Id: xhtml-print10.dtd,v 1.5 2003/10/24 14:24:40 fujisawa Exp $ --> <!-- This is the driver file for version 1.0 of the XHTML-Print DTD. This DTD is identified by the PUBLIC and SYSTEM identifiers: PUBLIC "-//W3C//DTD XHTML-Print 1.0//EN" SYSTEM "http://www.w3c.org/MarkUp/DTD/xhtml-print10.dtd" --> <!ENTITY % XHTML.version "-//W3C//DTD XHTML-Print 1.0//EN" > <!-- Use this URI to identify the default namespace: "http://www.w3.org/1999/xhtml" --> <!ENTITY % NS.prefixed "IGNORE" > <!ENTITY % XHTML.prefix "" > <!-- Reserved for use with the XLink namespace: --> <!ENTITY % XLINK.xmlns "" > <!ENTITY % XLINK.xmlns.attrib "" > <!-- reserved for future use with document profiles --> <!ENTITY % XHTML.profile "" > <!-- Bidirectional Text features This feature-test entity is used to declare elements and attributes used for bidirectional text support. --> <!ENTITY % XHTML.bidi "IGNORE" > <!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: --> <!ENTITY % xhtml-events.module "IGNORE" > <!ENTITY % xhtml-bdo.module "%XHTML.bidi;" > <!-- Style Attribute Module ............................ --> <!ENTITY % xhtml-inlstyle.module "INCLUDE" > <![%xhtml-inlstyle.module;[ <!ENTITY % xhtml-inlstyle.mod PUBLIC "-//W3C//ENTITIES XHTML Inline Style 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-inlstyle-1.mod" > %xhtml-inlstyle.mod;]]> <!-- Document Model Module ............................. --> <!ENTITY % xhtml-model.mod PUBLIC "-//W3C//ENTITIES XHTML-Print 1.0 Document Model 1.0//EN" "xhtml-print10-model-1.mod" > <!-- Modular Framework Module (required) ............... --> <!ENTITY % xhtml-framework.mod PUBLIC "-//W3C//ENTITIES XHTML Modular Framework 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-framework-1.mod" > %xhtml-framework.mod; <!-- Text Module (required) ............................ --> <!ENTITY % xhtml-text.mod PUBLIC "-//W3C//ELEMENTS XHTML Text 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-text-1.mod" > %xhtml-text.mod; <!-- Hypertext Module (required) ....................... --> <!ENTITY % xhtml-hypertext.mod PUBLIC "-//W3C//ELEMENTS XHTML Hypertext 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-hypertext-1.mod" > %xhtml-hypertext.mod; <!-- Lists Module (required) ........................... --> <!ENTITY % xhtml-list.mod PUBLIC "-//W3C//ELEMENTS XHTML Lists 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-list-1.mod" > %xhtml-list.mod; <!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: --> <!-- Presentation Module ............................... --> <!ENTITY % xhtml-pres.module "INCLUDE" > <![%xhtml-pres.module;[ <!ENTITY % xhtml-pres.mod PUBLIC "-//W3C//ELEMENTS XHTML Presentation 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-pres-1.mod" > %xhtml-pres.mod;]]> <!-- Image Module ...................................... --> <!ENTITY % xhtml-image.module "INCLUDE" > <![%xhtml-image.module;[ <!ENTITY % xhtml-image.mod PUBLIC "-//W3C//ELEMENTS XHTML Images 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-image-1.mod" > %xhtml-image.mod;]]> <!-- Tables Module ..................................... --> <!ENTITY % xhtml-table.module "INCLUDE" > <![%xhtml-table.module;[ <!ENTITY % xhtml-table.mod PUBLIC "-//W3C//ELEMENTS XHTML Basic Tables 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-basic-table-1.mod" > %xhtml-table.mod;]]> <!-- Forms Module ...................................... --> <!ENTITY % xhtml-form.module "INCLUDE" > <![%xhtml-form.module;[ <!ENTITY % xhtml-form.mod PUBLIC "-//W3C//ELEMENTS XHTML Basic Forms 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-basic-form-1.mod" > %xhtml-form.mod;]]> <!-- Scripting Module ................................. --> <!ENTITY % xhtml-script.module "INCLUDE" > <![%xhtml-script.module;[ <!ENTITY % xhtml-script.mod PUBLIC "-//W3C//ELEMENTS XHTML Scripting 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-script-1.mod" > %xhtml-script.mod;]]> <!-- Style Sheet Module ................................ --> <!ENTITY % xhtml-style.module "INCLUDE" > <![%xhtml-style.module;[ <!ENTITY % xhtml-style.mod PUBLIC "-//W3C//ELEMENTS XHTML Style Sheets 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-style-1.mod" > %xhtml-style.mod;]]> <!-- Link Module ....................................... --> <!ENTITY % xhtml-link.module "INCLUDE" > <![%xhtml-link.module;[ <!ENTITY % xhtml-link.mod PUBLIC "-//W3C//ELEMENTS XHTML Link Element 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-link-1.mod" > %xhtml-link.mod;]]> <!-- Metainformation Module ............................ --> <!ENTITY % xhtml-meta.module "INCLUDE" > <![%xhtml-meta.module;[ <!ENTITY % xhtml-meta.mod PUBLIC "-//W3C//ELEMENTS XHTML Metainformation 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-meta-1.mod" > %xhtml-meta.mod;]]> <!-- Base Module ....................................... --> <!ENTITY % xhtml-base.module "INCLUDE" > <![%xhtml-base.module;[ <!ENTITY % xhtml-base.mod PUBLIC "-//W3C//ELEMENTS XHTML Base Element 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-base-1.mod" > %xhtml-base.mod;]]> <!-- Param Module ...................................... --> <!ENTITY % xhtml-param.module "INCLUDE" > <![%xhtml-param.module;[ <!ENTITY % xhtml-param.mod PUBLIC "-//W3C//ELEMENTS XHTML Param Element 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-param-1.mod" > %xhtml-param.mod;]]> <!-- Object Module ..................................... --> <!ENTITY % xhtml-object.module "INCLUDE" > <![%xhtml-object.module;[ <!ENTITY % xhtml-object.mod PUBLIC "-//W3C//ELEMENTS XHTML Embedded Object 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-object-1.mod" > %xhtml-object.mod;]]> <!-- Structure Module (required) ....................... --> <!ENTITY % xhtml-struct.mod PUBLIC "-//W3C//ELEMENTS XHTML Document Structure 1.0//EN" "http://www.w3.org/TR/xhtml-modularization/DTD/xhtml-struct-1.mod" > %xhtml-struct.mod; <!-- end of XHTML-Print 1.0 DTD ............................................ --> <!-- ....................................................................... -->
Available for download at xhtml-print10-model-1.mod .
<!-- ....................................................................... --> <!-- XHTML-Print 1.0 Document Model Module ................................. --> <!-- file: xhtml-print10-model-1.mod This is XHTML-Print 1.0, a variant of XHTML Basic for printing. Copyright 1998-2003 W3C (MIT, ERCIM, Keio), All Rights Reserved. Revision: $Id: xhtml-print10-model-1.mod,v 1.7 2003/10/24 22:14:40 fujisawa Exp $ This DTD module is identified by the PUBLIC and SYSTEM identifiers: PUBLIC "-//W3C//ENTITIES XHTML-Print 1.0 Document Model 1.0//EN" SYSTEM "http://www.w3c.org/MarkUp/DTD/xhtml-print10-model-1.mod ....................................................................... --> <!-- XHTML-Print 1.0 Document Model This module describes the groupings of elements that make up common content models for XHTML-Print elements. --> <!-- Optional Elements in head ......................... --> <!ENTITY % HeadOpts.mix "( %script.qname; | %style.qname; | %meta.qname; | %link.qname; | %object.qname; )*" > <!-- Miscellaneous Elements ............................ --> <!ENTITY % Script.class "| %script.qname; | %noscript.qname;" > <!ENTITY % Misc.extra "" > <!ENTITY % Misc.class "%Script.class; %Misc.extra;" > <!-- Inline Elements ................................... --> <!ENTITY % InlStruct.class "%br.qname; | %span.qname;" > <!ENTITY % InlPhras.class "| %em.qname; | %strong.qname; | %dfn.qname; | %code.qname; | %samp.qname; | %kbd.qname; | %var.qname; | %cite.qname; | %abbr.qname; | %acronym.qname; | %q.qname;" > <!ENTITY % InlPres.class "| %tt.qname; | %i.qname; | %b.qname; | %big.qname; | %small.qname; | %sub.qname; | %sup.qname; " > <!ENTITY % I18n.class "" > <!ENTITY % Anchor.class "| %a.qname;" > <!ENTITY % InlSpecial.class "| %img.qname; | %object.qname;" > <!ENTITY % InlForm.class "| %input.qname; | %select.qname; | %textarea.qname; | %label.qname;" > <!ENTITY % Inline.extra "" > <!ENTITY % Inline.class "%InlStruct.class; %InlPhras.class; %InlPres.class; %Anchor.class; %InlSpecial.class; %InlForm.class; %Inline.extra;" > <!ENTITY % InlNoAnchor.class "%InlStruct.class; %InlPhras.class; %InlPres.class; %InlSpecial.class; %InlForm.class; %Inline.extra;" > <!ENTITY % InlNoAnchor.mix "%InlNoAnchor.class; %Misc.class;" > <!ENTITY % Inline.mix "%Inline.class; %Misc.class;" > <!-- Block Elements .................................... --> <!ENTITY % Heading.class "%h1.qname; | %h2.qname; | %h3.qname; | %h4.qname; | %h5.qname; | %h6.qname;" > <!ENTITY % List.class "%ul.qname; | %ol.qname; | %dl.qname;" > <!ENTITY % Table.class "| %table.qname;" > <!ENTITY % Form.class "| %form.qname;" > <!ENTITY % BlkStruct.class "%p.qname; | %div.qname;" > <!ENTITY % BlkPhras.class "| %pre.qname; | %blockquote.qname; | %address.qname;" > <!ENTITY % BlkPres.class "| %hr.qname;" > <!ENTITY % BlkSpecial.class "%Table.class; %Form.class;" > <!ENTITY % Block.extra "" > <!ENTITY % Block.class "%BlkStruct.class; %BlkPhras.class; %BlkPres.class; %BlkSpecial.class; %Block.extra;" > <!ENTITY % Block.mix "%Heading.class; | %List.class; | %Block.class; %Misc.class;" > <!-- All Content Elements .............................. --> <!ENTITY % FlowNoTable.mix "%Heading.class; | %List.class; | %BlkStruct.class; %BlkPhras.class; %BlkPres.class; %Form.class; %Block.extra; | %Inline.class; %Misc.class;" > <!ENTITY % Flow.mix "%Heading.class; | %List.class; | %Block.class; | %Inline.class; %Misc.class;" > <!-- end of xhtml-print10-model-1.mod -->
none