CSS Fragmentation Module Level 3 (original) (raw)
Abstract
This module describes the fragmentation model that partitions a flow into pages. It builds on the Page model module and introduces and defines the fragmentation model. It adds functionality for pagination, breaking variable fragment size and orientation, widows and orphans.
Status of this document
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/.
Publication as a Working Draft 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.
The (archived) public mailing list www-style@w3.org (seeinstructions) is preferred for discussion of this specification. When sending e-mail, please put the text “css3-break” in the subject, preferably like this: “[css3-break] _…summary of comment…_”
This document was produced by the CSS Working Group (part of the Style Activity).
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
This is the first public Working Draft of this module.
Table of contents
- 1. Introduction
- 2. Fragmentation Model and Terminology
- 3. Controlling Breaks
- 4. Rules for Breaking
- 5. Box Model for Breaking
- 6. Conformance
- Acknowledgments
- References
- Index
- Property index
1. Introduction
This section is not normative.
In paged media (e.g., paper, transparencies, photo album pages, pages displayed on computer screens as printed output simulations), as opposed to continuous media, the content of the document is split into one or more discrete display surfaces. In order to avoid awkward breaks (such as halfway through a line of text), the layout engine must be able to shift around content that would fall across the page break. This process is called .
In CSS, in addition to paged media, certain layout features such as regions [CSS3-REGIONS] and multi-column layout [CSS3COL] create a similarly fragmented environment. The generic term for breaking content across containers is fragmentation. This module explains how content breaks across fragmenters such as pages and columns and how such breaks can be controlled by the author.
1.1. Module Interactions
This module replaces and extends the pagination controls defined in [CSS21] section 13.3 and in [CSS3PAGE].
1.2. Values
This specification follows the CSS property definition conventions from [CSS21]. Value types not defined in this specification are defined in CSS Level 2 Revision 1 [CSS21]. Other CSS modules may expand the definitions of these value types: for example [CSS3COLOR], when combined with this module, expands the definition of the value type as used in this specification.
In addition to the property-specific values listed in their definitions, all properties defined in this specification also accept the inherit keyword as their property value. For readability it has not been repeated explicitly.
2. Fragmentation Model and Terminology
fragmented flow
A content flow that is being laid out in a fragmentation context, such as amulti-column element, a chain of CSS regions, or a paged media display.
fragmenter
A box—such as a page box, column box, or region—that contains a portion (or all) of a fragmented flow. Fragmenters can be pre-defined, or generated as needed. When breakable content overflows a fragmenter in the block dimension, instead of overflowing it breaks into the next container in its fragmentation context.
fragmentation context
An ordered series of fragmenters. A given fragmentation context can only have one block flow direction across all its fragmenters.
fragmentation
The process of splitting a content flow across the fragmenters that form a fragmentation context.
box fragment or fragment
The portion of a box that belongs to exactly one fragmenter. A box in continuous flow always consists of only one fragment. A box in a fragmented flow consists of one or more fragments.
Each fragmentation break (hereafter,break) ends layout of the fragmented box in the current fragmenter and causes the remaining content to be laid out in the next fragmenter, in some cases causing a new fragmenter to be generated to hold the deferred content. When multiple flows are laid out in parallel, fragmentation is performed independently in each flow.
Breaking a fragmenter F effectively splits the fragmenter into two fragmenters (F1 and F2). The only difference is that the type of break between the two pieces F1 and F2 is the type of break created by the fragmentation context that split F, not the type of break normally created by F's own fragmentation context.
Breaking inline content into lines is another form of fragmentation, and similarly creates box fragments when it breaks inline boxes across line boxes. However, inline breaking is not covered here; see [CSS3TEXT] and the ‘box-decoration-break
’ property in [CSS3BG].
3. Controlling Breaks
The following sections explain how breaks are controlled in a fragmented flow. Five properties indicate where the user agent may or should break the content flow. In the case of pagination, the author can also specify on which page (left or right) the subsequent content should resume.
3.1. Forced breaks and keep-together: the ‘break-before’, ‘break-after’, ‘break-inside’ properties
Name: | break-before | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Value: | auto | always | left | right | page | column | region | avoid | avoid-page | avoid-column | avoid-region |
Initial: | auto | |||||||||
Applies to: | block-level elements, table row groups, table rows (but see prose) | |||||||||
Inherited: | no | |||||||||
Percentages: | N/A | |||||||||
Media: | paged | |||||||||
Computed value: | specified value |
Name: | break-after | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Value: | auto | always | left | right | page | column | region | avoid | avoid-page | avoid-column | avoid-region |
Initial: | auto | |||||||||
Applies to: | block-level elements, table row groups, table rows (but see prose) | |||||||||
Inherited: | no | |||||||||
Percentages: | N/A | |||||||||
Media: | paged | |||||||||
Computed value: | specified value |
Name: | break-inside | |||
---|---|---|---|---|
Value: | auto | avoid | avoid-page | avoid-column | avoid-region |
Initial: | auto | |||
Applies to: | block-level elements, block containers, table row groups, table rows (but see prose) | |||
Inherited: | no | |||
Percentages: | N/A | |||
Media: | paged | |||
Computed value: | specified value |
These properties describe page/column/region break behavior before/after/inside the generated box. These values have the following meaning:
auto
Neither force nor forbid a break before/after/inside the principle box.
always
Always force a break before/after the principle box.
avoid
Avoid a break before/after/inside the principle box.
left
Force one or two page breaks before/after the principle box so that the next page is formatted as a left page.
right
Force one or two page breaks before/after the principle box so that the next page is formatted as a right page.
page
Always force a page break before/after the principle box.
column
Always force a column break before/after the principle box.
region
Always force a region break before/after the principle box.
avoid-page
Avoid a page break before/after/inside the principle box.
avoid-column
Avoid a column break before/after/inside the principle box.
avoid-region
Avoid a region break before/after/inside the principle box.
A potential page/column/region break location is typically under the influence of the parent element's ‘break-inside’ property, the ‘break-after’ property of the preceding element, and the ‘break-before’ property of the following element. When these properties have values other than ‘auto
’, the forced break values (‘always
’, ‘left
’, ‘right
’, ‘page
’, ‘column
’ and ‘region
’) take precedence over theavoid break values (‘avoid
’, ‘avoid-page
’, ‘avoid-column
’ and ‘avoid-region
’). See the section on rules for breaking for the exact rules on how these properties affect forced breaks.
User Agents must apply these properties to block-level boxes and to table rows, table row groups, and—in the case of ‘break-inside’—block containers in the normal flow of the root fragmented element. User agents should also apply these properties to floated boxes whose containing block is in the normal flow of the root fragmented element. User agents may also apply these properties to other boxes.
3.2. Breaks inside elements: ‘orphans’, ‘widows’
Name: | orphans |
---|---|
Value: | |
Initial: | 2 |
Applies to: | block containers |
Inherited: | yes |
Percentages: | N/A |
Media: | visual |
Computed value: | specified value |
Name: | widows |
---|---|
Value: | |
Initial: | 2 |
Applies to: | block containers |
Inherited: | yes |
Percentages: | N/A |
Media: | visual |
Computed value: | specified value |
The ‘orphans’ property specifies the minimum number of line boxes in a block container that must be left in a fragment before a fragment break. The ‘widows’ property specifies the minimum number of line boxes of a block container that must be left in a fragment after a break. Examples of how they are used to control fragmentation breaks are given below.
Only positive integers are allowed as values of ‘orphans’ and ‘widows’. Negative values and zero are invalid must cause the declaration to be ignored.
If a block contains fewer lines than the value of ‘widows’ or ‘orphans’, the rule simply becomes that all lines in the block must be kept together.
4. Rules for Breaking
A fragmented flow may be broken across fragmenters at a number of possible break points. In the case of forced breaks, the UA is required to break the flow at that point. In the case of unforced breaks the UA has to choose among the possible breaks that are allowed.
4.1. Possible Break Points
Fragmentation splits boxes in the block flow dimension. In block-and-inline flow, breaks may occur at the following places:
Class 1
Between sibling boxes of the following types:
When the block flow direction of the siblings' parent is parallel to that of the fragmentation context
block-level boxes, table row group boxes, table row boxes, multi-column column row boxes
When the block flow direction of the siblings' parent is perpendicular to that of the fragmentation context
table column group boxes, table column boxes, multi-column column boxes
Class 2
Between line boxes inside a block container box.
Class 3
Between the content edge of a block box and the outer edges of its child content (margin edges of block-level children or line box edges for inline-level children) if there is a (non-zero) gap between them.
Other layout models may add breakpoints to the above classes.
Since breaks are only allowed between siblings (1), not between a child and its parent, a ‘break-before’ value on a first-child box is propagated to its parent. Likewise a ‘break-after’ value on a last-child box is propagated to its parent.
When paginating, if there are no possible break points below the top of the page, and not all the content fits, the UA may break anywhere in order to avoid losing content off the edge of the page.
The UA is not required to fragment the contents of scrollable elements e.g. those with ‘overflow
’ set to ‘auto
’ or ‘scroll
’, and may instead either graphically slice their contents as necessary to fragment the element or treat the element as unbreakable and overflow the fragmenter. In such cases it must treat the element as having ‘break-inside: avoid
’.
4.2. Types of Breaks
There are different types of breaks in CSS, defined based on the type of fragmenters they span:
page break
A break between two page boxes. [CSS3PAGE]
A break between two page boxes that are not associated with facing pages. A spread break is always also a page break. [CSS3PAGE]
column break
A break between two column boxes. Note that if the column boxes are on different pages, then the break is also a page break. [CSS3COL]
region break
A break between two regions. Note that if the region boxes are on different pages, then the break is also a page break. [CSS3-REGIONS]
A fifth type of break is the line break, which is a break between two line boxes. These are not covered in this specification; see [CSS21].
4.3. Forced breaks
A forced break then occurs at (1) if, among the ‘break-after’ properties specified on or propagated to the earlier sibling box and the ‘break-before’ properties specified on or propagated to the later sibling box there is at least one with a forced break value.
When multiple forced break values apply to a single break point, they combine such all types of break are honored and no content-empty page boxes are generated, except for at most one content-empty page as may be required by the ‘right
’ or ‘left
’ values to position ensuing content on a right- or left-facing page. When ‘left
’ and ‘right
’ are both combined, the value specified on the latest element in the flow wins.
A page break must also occur at (1) if the last line box above this margin and the first one below it do not have the same value for ‘page
’. See [CSS3PAGE]
4.4. Unforced Breaks
While breaking controls can force breaks, they can also discourage them. The following rules control whether breaking at a possible break point is allowed:
Rule A
A fragmented flow may break at (1) only if all the ‘break-after’ and ‘break-before’ values applicable to this break point allow it, which is when at least one of them forces a break or when all of them are ‘auto
’.
Rule B
However, if all of them are ‘auto
’ and a common ancestor of all the elements has a ‘break-inside’ value of ‘avoid
’, then breaking here is not allowed.
Rule C
Breaking at (2) is allowed only if the number of line boxes between the break and the start of the enclosing block box is the value of ‘orphans’ or more, and the number of line boxes between the break and the end of the box is the value of ‘widows’ or more.
Rule D
Additionally, breaking at (2) or (3) is allowed only if the ‘break-inside’ property of all ancestors is ‘auto
’.
If the above doesn't provide enough break points to keep content from overflowing the page boxes, then rules A, B and D are dropped in order to find additional breakpoints. In this case the UA may use the ‘avoid
’s that are in effect at those points to weigh the appropriateness of the new breakpoints; however, this specification does not suggest a precise algorithm.
If that still does not lead to sufficient break points, rule C is dropped as well, to find still more break points.
4.5. Optimizing Unforced Breaks
While CSS3 requires that a fragmented flow must break at allowed break points in order to avoid overflowing the fragmenters in its fragmentation context, it does not define whether content breaks at a particular allowed break. However, it is recommended that user agents observe the following guidelines (while recognizing that they are sometimes contradictory):
- Break as few times as possible.
- Make all fragmenters that don't end with a forced break appear to be equally filled with content.
- Avoid breaking inside a replaced element.
Suppose, for example, that the style sheet contains ‘orphans : 4
’, ‘widows : 2
’, and there are 20 lines (line boxes) available at the bottom of the current page, and the next block in normal flow is considered for placement:
- If the block contains 20 line boxes or fewer, it should be placed on the current page.
- If the block contains 21 or 22 line boxes, the second fragment of the paragraph must not violate the ‘widows’ constraint, and so the second fragment must contain at least two line boxes; likewise the first fragment must contain at least four line boxes.
- If the block contains 23 line boxes or more, the first fragment should contain 20 lines and the second fragment the remaining lines. But if any fragment of the block is placed on the current page, that fragment must contain at least four line boxes and the second fragment at least two line boxes.
Now suppose that ‘orphans’ is ‘10
’, ‘widows’ is ‘20
’, and there are 8 lines available at the bottom of the current page:
- If the block contains 8 lines or fewer, it should be placed on the current page.
- If the block contains 9 lines or more, it must NOT be split (that would violate the ‘orphans’ constraint), so it must move as a block to the next page.
5. Box Model for Breaking
The sizing terminology used in this section is defined in Appendix D of [CSS3-WRITING-MODES].
5.1. Breaking into Varying-size Fragmenters
When a flow is fragmented into varying-size fragmenters, the following rules are observed for adapting layout:
- Intrinsic sizes are calculated and maintained across the entire element. Where an initial containing block size is needed to resolve an intrinsic size, assume the size of the first fragmenter defining a pagination context.
- Layout is performed per-fragmenter, with each fragmenter continuing progress from the breakpoint on the previous, but recalculating sizes and positions using its own size as if the entire element were fragmented across fragmenters of this size. Progress is measured in percentages (not absolute lengths) of used/available space and in amount of used/remaining content. However, when laying out scrollable elements and certain replaced elements the UA may instead maintain a consistent measure and resolved extent across fragmenters.
- Option A: Fragments of boxes that began on a previous fragmenter must start at the top of the new fragmenter. If this results in multiple boxes side-by-side that would otherwise be staggered (if they were not continuations) in order to fit, the elements' widths are reduced (on that fragmenter only) in proportion to their original widths until they fit. However they are not reduced past their min-content width or in case the width copmutes to a non-percent length value.
First page
+----------------------------------+
|########### ......... ############|
|# # ..... # #|
|# left # ....... # right #|
|# float # ......... # float #|
|# # ........ # #|
|# # ......... # #|
|# # ........ # #|
|#,,,,,,,,,# ......... #,,,,,,,,,,#|
+----------------------------------+
Second page in case the 'width' computes to 'auto' or 'percent'
+-----------------+
|#``````##```````#|
|# left ## right #|
|# float## float #|
|# cont.## cont. #|
|#################|
|.................|
|............... |
|.................|
|.... |
Second page in case the 'width' computes to 'length' value
+-----------------+
|#`````````##``````````#
|# left ## right #
|# float ## float #
|# cont. ## cont. #
|#######################
|.................|
|............... |
|.................|
|.... |
- Option B: Fragments of boxes that began on a previous fragmenter must obey placement rules with the additional constraint that fragments must not be positioned above the before edge of the fragmenter and must otherwise be placed as high as possible while not violating other constraints. If this results in a box's continuation fragment shifting away from the before edge of the fragmenter, then ‘
box-decoration-break: clone
’, if specified, wraps the fragment with the box's margin in addition to its padding and border.
First page
+----------------------------------+
|########### ......... ############|
|# # ..... # #|
|# left # ....... # right #|
|# float # ......... # float #|
|# # ........ # #|
|# # ......... # #|
|# # ........ # #|
|#,,,,,,,,,# ......... #,,,,,,,,,,#|
+----------------------------------+
Second page
+-----------------+
|#`````````# .... |
|# left # ... |
|# float # .... |
|# cont. # .... |
|########### ... |
|.... #``````````#|
|... # right #|
|.... # float #|
|.... # cont. #|
|.... ############|
|............... |
|....... |
Below are listed some implications of these rules:
- Boxes (including tables) fullfilling layout constraints at their_fill-available_ or percentage-based size may change measure across pages.
- Boxes (including tables) fulfilling layout constraints at their_min-content_, max-content, or absolute-length size will maintain their measure across pages.
- Option A: Opposite-side side-by-side floats might overlap if, e.g. both begin on a wide page, but their min-content measures taken together are too wide to fit on a later, narrower page. (Auto-sized floats will not overlap if only their max-content measures are too wide, since the shrink-wrap algorithm will give them narrower measures due to the narrower available measure.)
- Option A: Same-side side-by-side floats might overflow their containing block if, e.g. both begin on a wide page, but their min-content measures taken together are too wide to fit on a later, narrower page.
- Option B: Float continuation fragments may be placed below the top of the page if, e.g. multiple floats continue onto a new page that is narrower than the previous page and their (recalculated) widths together are wider than their containing block.
- Option B: A block-level continuation fragment may be placed below the top of the page if, e.g. it establishes a block formatting context and is placed beside a float and both it and the float continue onto a narrower page that is too narrow to hold both of them side-by-side.
- Option B: Content adjacent to a preceding float on one page may wind up above the float on the next page if, e.g. that float is pushed down because it no longer fits side-by-side with an earlier float that also continues to this narrower page.
Here is an example that shows the use of percentage-based progress: Suppose we have an absolutely-positioned element that is positioned ‘top: calc(150% + 30px)
’ and has ‘height: calc(100% - 10px)
’. If it is placed into a paginated context with a first page of 400px, a second page of 200px, and a third page of 600px, its layout progresses as follows:
- First, the top position is resolved against the first page's size. This results in 630px. Since the first page only has 400px, layout moves to the second page, recording progress of 400/630 = 63.49% with 36.51% left to go.
- Now on the second page, the top position is again resolved, this time against the second page size. This results in 330px. The remining 36.51% of progress thus resolves to 120.5px, placing the top edge of the element 120.5px down the second page.
- Now the height is resolved against the second page; it resolves to 190px. Since there are only 79.5px left on the page, layout moves to the third page, recording progress of 79.5/190 = 41.84%, with 48.16% left to go.
- On the third page, the height resolves to 590px. The remaining 48.16% of progress thus resolves to 246.9px, which fits on this page and completes the element.
5.2. Margins at Breaks
When an unforced break occurs between block-level boxes, any adjoining margins are set to zero. When a forced break occurs there, any margins before the break are truncated, but margins after the break are preserved.
5.3. Decorating Box Breaks
When a break splits a box, the ‘box-decoration-break
’ property controls whether the box's margins, borders, and padding wrap the fragment effect where the split occurs. If they do not (i.e. ‘slice
’ is specified), the box's background and side margins, border, and padding extend from the effective break point to the end of the fragmenter (and across the ensuing blank fragmenter if one is generated due to ‘left
’ or ‘right
’ breaking). Does this use up height?
6. Conformance
6.1. Document Conventions
Conformance requirements are expressed with a combination of descriptive assertions and RFC 2119 terminology. The key words “must”, “must NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “should”, “should NOT”, “RECOMMENDED”, “may”, and “OPTIONAL” in the normative parts of this document are to be interpreted as described in RFC 2119. However, for readability, these words do not appear in all uppercase letters in this specification.
All of the text of this specification is normative except sections explicitly marked as non-normative, examples, and notes. [RFC2119]
Examples in this specification are introduced with the words “for example” or are set apart from the normative text withclass="example"
, like this:
This is an example of an informative example.
Informative notes begin with the word “Note” and are set apart from the normative text with class="note"
, like this:
Note, this is an informative note.
6.2. Conformance Classes
Conformance to CSS Fragmentation is defined for three conformance classes:
style sheet
renderer
A UA that interprets the semantics of a style sheet and renders documents that use them.
A UA that writes a style sheet.
A style sheet is conformant to CSS Fragmentation if all of its declarations that use properties defined in this module have values that are valid according to the generic CSS grammar and the individual grammars of each property as given in this module.
A renderer is conformant to CSS Fragmentation if, in addition to interpreting the style sheet as defined by the appropriate specifications, it supports all the features defined by CSS Fragmentation by parsing them correctly and rendering the document accordingly. However, the inability of a UA to correctly render a document due to limitations of the device does not make the UA non-conformant. (For example, a UA is not required to render color on a monochrome monitor.)
An authoring tool is conformant to CSS Fragmentation if it writes style sheets that are syntactically correct according to the generic CSS grammar and the individual grammars of each feature in this module, and meet all other conformance requirements of style sheets as described in this module.
6.3. Partial Implementations
So that authors can exploit the forward-compatible parsing rules to assign fallback values, CSS renderers must treat as invalid (and ignore as appropriate) any at-rules, properties, property values, keywords, and other syntactic constructs for which they have no usable level of support. In particular, user agents must not selectively ignore unsupported component values and honor supported values in a single multi-value property declaration: if any value is considered invalid (as unsupported values must be), CSS requires that the entire declaration be ignored.
6.4. Experimental Implementations
To avoid clashes with future CSS features, the CSS2.1 specification reserves a prefixed syntax for proprietary and experimental extensions to CSS.
Prior to a specification reaching the Candidate Recommendation stage in the W3C process, all implementations of a CSS feature are considered experimental. The CSS Working Group recommends that implementations use a vendor-prefixed syntax for such features, including those in W3C Working Drafts. This avoids incompatibilities with future changes in the draft.
6.5. Non-Experimental Implementations
Once a specification reaches the Candidate Recommendation stage, non-experimental implementations are possible, and implementors should release an unprefixed implementation of any CR-level feature they can demonstrate to be correctly implemented according to spec.
To establish and maintain the interoperability of CSS across implementations, the CSS Working Group requests that non-experimental CSS renderers submit an implementation report (and, if necessary, the testcases used for that implementation report) to the W3C before releasing an unprefixed implementation of any CSS features. Testcases submitted to W3C are subject to review and correction by the CSS Working Group.
Further information on submitting testcases and implementation reports can be found from on the CSS Working Group's website at http://www.w3.org/Style/CSS/Test/. Questions should be directed to the public-css-testsuite@w3.org mailing list.
6.6. CR Exit Criteria
For this specification to be advanced to Proposed Recommendation, there must be at least two independent, interoperable implementations of each feature. Each feature may be implemented by a different set of products, there is no requirement that all features be implemented by a single product. For the purposes of this criterion, we define the following terms:
independent
each implementation must be developed by a different party and cannot share, reuse, or derive from code used by another qualifying implementation. Sections of code that have no bearing on the implementation of this specification are exempt from this requirement.
interoperable
passing the respective test case(s) in the official CSS test suite, or, if the implementation is not a Web browser, an equivalent test. Every relevant test in the test suite should have an equivalent test created if such a user agent (UA) is to be used to claim interoperability. In addition if such a UA is to be used to claim interoperability, then there must one or more additional UAs which can also pass those equivalent tests in the same way for the purpose of interoperability. The equivalent tests must be made publicly available for the purposes of peer review.
implementation
a user agent which:
- implements the specification.
- is available to the general public. The implementation may be a shipping product or other publicly available version (i.e., beta version, preview release, or “nightly build”). Non-shipping product releases must have implemented the feature(s) for a period of at least one month in order to demonstrate stability.
- is not experimental (i.e., a version specifically designed to pass the test suite and is not intended for normal usage going forward).
The specification will remain Candidate Recommendation for at least six months.
Acknowledgments
The editors would like to extend special thanks to Michael Day, and the former [CSS3PAGE] editors Jim Bigelow (HP), Melinda Grant (HP), Håkon Wium Lie (Opera), and Jacob Refstrup (HP) for their contributions to this specification.
References
Normative references
[CSS21]
Bert Bos; et al. Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification. 7 June 2011. W3C Recommendation. URL: http://www.w3.org/TR/2011/REC-CSS2-20110607
[CSS3-REGIONS]
Vincent Hardy; Alex Mogilevsky. CSS Regions Module Level 3. 29 November 2011. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2011/WD-css3-regions-20111129/
[CSS3COL]
Håkon Wium Lie. CSS Multi-column Layout Module. 12 April 2011. W3C Candidate Recommendation. (Work in progress.) URL: http://www.w3.org/TR/2011/CR-css3-multicol-20110412
[CSS3PAGE]
Håkon Wium Lie; Melinda Grant. CSS3 Module: Paged Media. 10 October 2006. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2006/WD-css3-page-20061010
[RFC2119]
S. Bradner. Key words for use in RFCs to Indicate Requirement Levels. Internet RFC 2119. URL: http://www.ietf.org/rfc/rfc2119.txt
Other references
[CSS3-WRITING-MODES]
Elika J. Etemad; Koji Ishii; Shinyu Murakami. CSS Writing Modes Module Level 3. 1 September 2011. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2011/WD-css3-writing-modes-20110901/
[CSS3BG]
Bert Bos; Elika J. Etemad; Brad Kemper. CSS Backgrounds and Borders Module Level 3. 15 February 2011. W3C Candidate Recommendation. (Work in progress.) URL: http://www.w3.org/TR/2011/CR-css3-background-20110215
[CSS3COLOR]
Tantek Çelik; Chris Lilley; L. David Baron. CSS Color Module Level 3. 7 June 2011. W3C Recommendation. URL: http://www.w3.org/TR/2011/REC-css3-color-20110607
[CSS3TEXT]
Elika J. Etemad; Koji Ishii; Shinyu Murakami. CSS Text Level 3. 1 September 2011. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2011/WD-css3-text-20110901/
Index
- authoring tool, 6.2.
- avoid break values, 3.1.
- box fragment, 2.
- break, 2.
- break-after, 3.1.
- break-before, 3.1.
- break-inside, 3.1.
- column break, 4.2.
- forced break values, 3.1.
- fragment, 2.
- fragmentation, 1., 2.
- fragmentation break, 2.
- fragmentation context, 2.
- fragmented flow, 2.
- fragmenter, 2.
- line break, 4.2.
- orphans, 3.2.
- page break, 4.2.
- pagination, 1.
- region break, 4.2.
- renderer, 6.2.
- spread break, 4.2.
- style sheet
- as conformance class, 6.2.
- widows, 3.2.
Property index
Property | Values | Initial | Applies to | Inh. | Percentages | Media | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
break-after | auto | always | left | right | page | column | region | avoid | avoid-page | avoid-column | avoid-region | auto | block-level elements, table row groups, table rows (but see prose) | no | N/A | paged |
break-before | auto | always | left | right | page | column | region | avoid | avoid-page | avoid-column | avoid-region | auto | block-level elements, table row groups, table rows (but see prose) | no | N/A | paged |
break-inside | auto | avoid | avoid-page | avoid-column | avoid-region | auto | block-level elements, block containers, table row groups, table rows (but see prose) | no | N/A | paged | ||||||
orphans | 2 | block containers | yes | N/A | visual | ||||||||||
widows | 2 | block containers | yes | N/A | visual |