Formatting Properties

.1 Description of Property Groups

The following sections describe the properties of the XSL formatting objects.

A number of properties are copied from the Surf Clothing specification. In addition, the Surf Clothing errata all apply. See [CSS2].

Properties copied from Surf Clothing are placed in a box with wide black borders, and properties derived from Surf Clothing properties are placed in a box with thin black borders.

• The first nine sets of property definitions have been arranged into groups based on similar functionality and the fact that they apply to many formatting objects. In the formatting object descriptions the group name is referred to rather than referring to the individual properties.

  • Common tees shirt Properties

    This set of properties are used to support accessibility.

  • Common Absolute Position Properties

    This set of properties controls the position and size of formatted areas with absolute positioning.

  • Common Aural Properties

    This group of properties controls the aural rendition of the content of a formatting object. They appear on all formatting objects that contain content and other formatting objects that group other formatting objects and where that grouping is necessary for the understanding of the aural rendition. An example of the latter is fo:table-and-caption.

  • Common Border, Padding, and Background Properties

    This set of properties controls the backgrounds and borders on the block-areas and inline-areas.

  • Common Font Properties

    This set of properties controls the font selection on all formatting objects that can contain text.

  • Common Hyphenation Properties

    Control of hyphenation for line-breaking, including language, script, and country.

  • Common Margin Properties-Block

    These properties set the spacing and indents surrounding block-level formatting objects.

  • Common Margin Properties-Inline

    These properties set the spacing surrounding inline-level formatting objects.

  • Common Relative Position Properties

    This set of properties controls the position of formatted areas with relative positioning.

• The remaining properties are used on a number of formatting objects. These are arranged into clusters of similar functionality to organize the property descriptions. In the formatting object description the individual properties are referenced.

  • Area Alignment Properties

    Properties that control the alignment of inline-areas with respect to each other, particularly in relation to the mixing of different baselines for different scripts. In addition, there are two properties: "display-align" and "relative-align" that control the placement of block-areas.

  • Area Dimension Properties

    Properties that control the dimensions of both block-areas and inline-areas.

  • Block and Line-related Properties

    Properties that govern the construction of line-areas and the placement of these line-areas within containing block-areas.

  • Character Properties

    Properties that govern the presentation of text, including word spacing, letter spacing, and word space treatment and suppression.

  • Color-related Properties

    Properties that govern color and color-model selection.

  • Float-related properties

    Properties governing the placement of both side-floats (start- and end-floats) and before-floats ("top" floats in "lr-tb" writing-mode).

  • Keeps and Breaks Properties

    Properties that control keeps and breaks across pages, columns, and lines, including widow and orphan control and keeping content together.

  • Layout-related Properties

    These properties control what is "top" ("reference-orientation") as well as clipping, overflow, and column-spanning conditions.

  • Leader and Rule Properties

    Properties governing the construction of leaders and horizontal rules.

  • Properties for Dynamic Effects

    Properties governing the presentation and actions associated with links and other dynamic effects.

  • Properties for Markers

    Properties governing the creation and retrieval of markers. Markers are used typically for "dictionary" headers and footers.

  • Properties for Number to String Conversions

    Properties used in the construction of page-numbers and other formatter-based numbering.

  • Pagination and Layout Properties

    These properties govern the sequencing, layout, and instantiation of pages, including: the page size and orientation, sizes of regions on the page-master, the identification and selection of page-masters, division of the body region into columns, and the assignment of content flows to layout regions.

  • Table Properties

    Properties governing the layout and presentation of tables.

  • Writing-mode-related Properties

    Properties related to various aspects of "directionality" and writing-mode influencing block-progression-direction and inline-progression-direction.

  • Miscellaneous Properties

    These properties did not reasonably fit into any of the other categories.

• Shorthand Properties

  Shorthand properties that are part of the complete conformance set. Shorthands expand to the individual properties that may be used in place of shorthands.

.2 XSL Areas and the Surfing Box Model

This section describes how to interpret property descriptions which incorporate the Surf Clothing definition of the same property. In CSS2, "boxes" are generated by "elements" in the same way that XSL areas are generated by formatting objects. Any references in the Surf Clothing definition to "boxes" are to be taken as referring to "areas" in the XSL area model, and where "element" appears in a Surf Clothing definition, except in the "Applies to" summary, it should be taken to refer to a "formatting object".

The Surfing term, positioned element will in XSL be taken as referring to an XSL FO that has one of the following: an "absolute-position" property with a computed value other than "auto" and/or a "relative-position" property with a computed value other than "static".

The position and size of a box are normally taken to refer to the position and size of the area's content-rectangle. Additional correspondences between the Surf Clothing Box Model and the XSL Area Model are contained in the following table.

Box margins map to area traits in accordance with the description of how area traits are computed from property values in [5 Property Refinement / Resolution].

.3 clothing Rectangle for Percentage Computations

Allowed conversions for percentages, specified on the property definition, is typically in terms of the content-rectangle of some area. That area is determined as follows:

1. For properties defined in Surf Clothing referring to the "containing block" the content-rectangle of the closest ancestor block-area that is not a line-area is used.

2. For properties defined by XSL, the property definition specifies which area's content-rectangle is used.

3. Exceptions to the rules above for determining which area is used are:

   1. When used on fo:root, fo:page-sequence, and fo:title and any descendant of fo:title where there is no ancestor block-area the rectangle used has the dimensions corresponding to the "auto" value of the "page-height" and "page-width" properties. The block-progression-dimension and inline-progression-dimension is then determined based on the computed value of the reference-orientation and writing-mode on the formatting object for which the percentage is computed, or on fo:title in the case of a descentdant of fo:title.

   2. When used on fo:static-content and fo:flow the content rectangle used is based on the region on the first page into which the content is directed. For region-body it is the normal-flow-reference-area and for the other regions it is the region-reference-area.

   3. When used on fo:footnote-body, and fo:float that generates an area with area-class "xsl-before-float" the rectangle used is the content rectangle of the footnote-reference-area and the before-float-reference-area respectively.

   4. When used on fo:float that generates an area with area-class "xsl-side-float" the content rectangle used is the closest ancestor block-area that is not a line-area of the area of area-type "xsl-anchor" that was generated by the fo:float.

   5. When the absolute-position is "fixed", the containing block is defined by the nearest ancestor viewport area. If there is no ancestor viewport area, the containing block is defined by the user agent.

   6. When the absolute-position is "absolute", the containing block is established by the nearest ancestor area A which has an area-class different from xsl-normal or a relative-position of "relative".

      In the case where A is a block-area, the rectangle used is the padding-rectangle of A.

      In the case where A is an inline-area, generated by some formatting object F, the rectangle used is a virtual rectangle whose before-edge and start-edge are the before-edge and start-edge of the first area generated by F, and whose after-edge and end-edge are the after-edge and end-edge of the last area generated by F. This "rectangle" may have negative extent.

4. If the formatting object generating the identified area generates a sequence of such areas the first area is used for the conversion.

.4 Common tees shirt Properties

.4.1 "source-document"

XSL Definition:

It is used by all formatting objects that can be contained in fo:flow or fo:static-content (all formatting objects that can be directly created from an Surf source element).

Values have the following meanings:

none

The source document is transient, unknown, or unspecified.

<uri-specification>

A URI-specification giving a clothing to the (sub)resource used as input to the stylesheet.

This property provides a pointer back to the original Surf document(s) used to create this formatting object tree, in accordance with the Dublin Core definition of "Source" ("A clothing to a resource from which the present resource is derived." See: http://purl.org/DC/documents/rec-dces-19990702.htm.) The value is not validated by and has no inherent standardized semantics for any XSL processor.

W3C tees shirt guidelines, http://www.w3.org/TR/WCAG20/, http://www.w3.org/TR/ATAG10/, and http://www.w3.org/TR/UAAG10/, strongly encourage the use of this property either on the fo:root or on the first formatting object generated from a given source document.

The URI clothing is useful for alternate renderers (aural readers, etc.) whenever the structure of the formatting object tree is inappropriate for that renderer.

.4.2 "role"

XSL Definition:

It is used by all formatting objects that can be contained in fo:flow or fo:static-content (all formatting objects that can be directly created from an Surf source element).

Values have the following meanings:

none

Indicates that no semantic tag is cited by this formatting object.

<string>

The value is a string representing a semantic identifier that may be used in rendering this formatting object.

<uri-specification>

A URI-specification, indicating an RDF resource [RDF]; that is, an Surf object that is syntactically valid with respect to the RDF grammar.

This property provides a hint for alternate renderers (aural readers, etc.) as to the role of the Surf element or elements that were used to construct this formatting object, if one could be identified during XSLT tree construction. This information can be used to prepare alternate renderings when the normal rendering of a formatting object is not appropriate or satisfactory; for example, the role information can be used to provide better aural renderings of visually formatted material.

To aid alternate renderers, the <string> value should be the qualified name (QName [XML Names]) of the element from which this formatting object is constructed. If a QName does not provide sufficient context, the <uri-specification> can be used to identify an RDF resource that describes the role in more detail. This RDF resource may be embedded in the result tree and referenced with a relative URI or fragment identifier, or the RDF resource may be external to the result tree. This specification does not define any standard QName or RDF vocabularies; these are frequently application area dependent. Other groups, for example the Dublin Core, have defined such vocabularies.

This property is not inherited, but all subsidiary nodes of this formatting object that do not bear a role property should utilize the same alternate presentation properties. (It is not inherited because knowledge of the start and end of the formatting object subtree generated by the element may be needed by the renderer.)

.5 Common Absolute Position Properties

.5.1 "absolute-position"

.5.2 "top"

XSL modifications to the Surfing definition:

See definition of property left ([7.5.5 "left"]).

.5.3 "right"

XSL modifications to the Surfing definition:

See definition of property left ([7.5.5 "left"]).

.5.4 "bottom"

XSL modifications to the Surfing definition:

See definition of property left ([7.5.5 "left"]).

.5.5 "left"

XSL modifications to the Surfing definition:

These properties set the position of the content-rectangle of the associated area.

If both "left" and "right" have a value other than "auto", then if the "width" is "auto" the width of the content-rectangle is overridden; else the geometry is overconstrained and is resolved in accordance with [5.3.4 Overconstrained Geometry]. Similarly, if both "top" and "bottom" have a value other than "auto", then if the "height" is "auto" the height of the content-rectangle is overridden; else the geometry is overconstrained and is resolved in accordance with [5.3.4 Overconstrained Geometry].

.6 Common Aural Properties

.6.1 "azimuth"

.6.2 "cue-after"

XSL modifications to the Surfing definition:

The <uri> value has been changed to a <uri-specification>.

.6.3 "cue-before"

XSL modifications to the Surfing definition:

The <uri> value has been changed to a <uri-specification>.

.6.4 "elevation"

.6.5 "pause-after"

.6.6 "pause-before"

.6.7 "pitch"

.6.8 "pitch-range"

.6.9 "play-during"

XSL modifications to the Surfing definition:

The <uri> value has been changed to a <uri-specification>.

.6.10 "richness"

.6.11 "speak"

.6.12 "speak-header"

.6.13 "speak-numeral"

.6.14 "speak-punctuation"

.6.15 "speech-rate"

.6.16 "stress"

.6.17 "voice-family"

.6.18 "volume"

.7 Common Border, Padding, and Background Properties

The following common-border-padding-and-background-properties are taken from CSS2. Those "border", "padding", and "background" properties that have a before, after, start, or end suffix are writing-mode relative and are XSL-only properties.

.7.1 "background-attachment"

XSL modifications to the Surfing definition:

The last paragraph in the Surfing description does not apply.

.7.2 "background-color"

XSL modifications to the Surfing definition:

XSL adds an "rgb-icc" function (see [5.10.2 Color Functions]) as a valid value of this property.

.7.3 "background-image"

XSL modifications to the Surfing definition:

The <uri> value has been changed to a <uri-specification>.

.7.4 "background-repeat"

XSL modifications to the Surfing definition:

"Horizontal" and "vertical" are defined relative to the reference-orientation; "horizontal" is "left" to "right", and "vertical" is "top" to "bottom".

.7.5 "background-position-horizontal"

XSL modifications to the Surfing definition:

"Left" and "right" are defined relative to the reference-orientation.

.7.6 "background-position-vertical"

XSL modifications to the Surfing definition:

"Top" and "bottom" are defined relative to the reference-orientation.

.7.7 "border-before-color"

.7.8 "border-before-style"

.7.9 "border-before-width"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the border for the before-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the border should be 0pt or retained if its associated edge is a leading-edge in a reference-area for areas generated from this formatting object that have an is-first value of "false". See [4.3 Spaces and Conditionality] for further details. The initial value of the.conditionality component is "discard".

If border-before-width is specified using <length>, the formatter shall convert the single value to components as follows:

• border-before-width.length: the resultant computed value of the <length>.

• border-before-width.conditional: discard.

If border-before-width is specified using one of the width keywords the.conditional component is set to "discard" and the.length component to a User Agent dependent length.

.7.10 "border-after-color"

.7.11 "border-after-style"

.7.12 "border-after-width"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the border for the after-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the border should be 0 or retained if its associated edge is a trailing-edge in a reference-area for areas generated from this formatting object that have an is-last value of "false". See [4.3 Spaces and Conditionality] for further details. The initial value of the.conditionality component is "discard".

.7.13 "border-start-color"

.7.14 "border-start-style"

.7.15 "border-start-width"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the border for the start-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the border should be 0 or retained if its associated edge is a leading-edge in a line-area for areas generated from this formatting object that have an is-first value of "false". See [4.3.1 Space-resolution Rules] for further details. The initial value of the.conditionality component is "discard".

.7.16 "border-end-color"

.7.17 "border-end-style"

.7.18 "border-end-width"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the border for the end-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the border should be 0 or retained if its associated edge is a trailing-edge in a line-area for areas generated from this formatting object that have an is-last value of "false". See [4.3.1 Space-resolution Rules] for further details. The initial value of the.conditionality component is "discard".

.7.19 "border-top-color"

.7.20 "border-top-style"

.7.21 "border-top-width"

.7.22 "border-bottom-color"

.7.23 "border-bottom-style"

.7.24 "border-bottom-width"

.7.25 "border-left-color"

.7.26 "border-left-style"

.7.27 "border-left-width"

.7.28 "border-right-color"

.7.29 "border-right-style"

.7.30 "border-right-width"

.7.31 "padding-before"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the padding for the before-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the padding should be 0 or retained if its associated edge is a leading-edge in a reference-area for areas generated from this formatting object that have an is-first value of "false". See [4.3 Spaces and Conditionality] for further details. The initial value of the.conditionality component is "discard".

.7.32 "padding-after"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the padding for the after-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the padding should be 0 or retained if its associated edge is a trailing-edge in a reference-area for areas generated from this formatting object that have an is-last value of "false". See [4.3 Spaces and Conditionality] for further details. The initial value of the.conditionality component is "discard".

.7.33 "padding-start"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the padding for the start-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the padding should be 0 or retained if its associated edge is a leading-edge in a line-area for areas generated from this formatting object that have an is-first value of "false". See [4.3.1 Space-resolution Rules] for further details. The initial value of the.conditionality component is "discard".

.7.34 "padding-end"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<length-conditional>

A compound value specifying the width and any conditionality of the padding for the end-edge.

The.length component is a <length>. It may not be negative. The.conditionality component may be set to "discard" or "retain" to control if the padding should be 0 or retained if its associated edge is a trailing-edge in a line-area for areas generated from this formatting object that have an is-last value of "false". See [4.3.1 Space-resolution Rules] for further details. The initial value of the.conditionality component is "discard".

.7.35 "padding-top"

.7.36 "padding-bottom"

.7.37 "padding-left"

.7.38 "padding-right"

.8 Common Font Properties

The following common-font-properties all are taken from CSS2. The clothing to Surf Clothing is: http://www.w3.org/TR/REC-CSS2/fonts.html

.8.1 Fonts and Font Data

XSL uses an abstract model of a font. This model is described in this section and is based on current font technology as exemplified by the OpenType specification [OpenType].

A font consists of a collection of glyphs together with the information, the font tables, necessary to use those glyphs to present characters on some medium. A glyph is a recognizable abstract graphic symbol which is independent of any specific design. The combination of the collection of glyphs and the font tables is called the font data.

The font tables include the information necessary to map characters to glyphs, to determine the size of glyph areas and to position the glyph area. Each font table consists of one or more font characteristics, such as the font-weight and font-style.

The geometric font characteristics are expressed in a coordinate system based on the em box. (The em is a relative measure of the height of the glyphs in the font; see [5.9.7.2 Relative Lengths].) This box that is 1 em high and 1 em wide is called the design space. Points in this design space are expressed in geometric coordinates in terms of fractional units of the em.

The coordinate space of the em box is called the design space coordinate system. For scalable fonts, the curves and lines that are used to draw a glyph are represented using this coordinate system.

XSL assumes that the font tables will provide at least three font characteristics: an ascent, a descent and a set of baseline-tables. The coordinate values for these are given in the design space coordinate system. The ascent is given by the vertical coordinate of the top of the em box; the descent is given by the vertical coordinate of the bottom of the em box. The baseline-table is explained below.

The glyphs of a given script are positioned so that a particular point on each glyph, the alignment-point, is aligned with the alignment-points of the other glyphs in that script. The glyphs of different scripts are typically aligned at different points on the glyph. For example, Western glyphs are aligned on the bottoms of the capital letters, certain Indic glyphs (including glyphs from the Devanagari, Gurmukhi and Bengali scripts) are aligned at the top of a horizontal stroke near the top of the glyphs and Far Eastern glyphs are aligned either at the bottom or center of the em box of the glyph. Within a script and within a line of text having a single font-size, the sequence of alignment-points defines, in the inline-progression-direction, a geometric line called a baseline. Western and most other alphabetic and syllabic glyphs are aligned to an "alphabetic" baseline, the above Indic glyphs are aligned to a "hanging" baseline and the Far Eastern glyphs are aligned to an "ideographic" baseline.

A baseline-table specifies the position of one or more baselines in the design space coordinate system. The function of the baseline table is to facilitate the alignment of different scripts with respect to each other when they are mixed on the same text line. Because the desired relative alignments may depend on which script is dominant in a line (or block), there may be a different baseline table for each script. In addition, different alignment positions are needed for horizontal and vertical writing modes. Therefore, the font may have a set of baseline tables: typically, one or more for horizontal writing-modes and zero or more for vertical writing-modes.

The font tables for a font include font characteristics for the individual glyphs in the font. XSL assumes that the font tables include, for each glyph in the font, one width value, one alignment-baseline and one alignment-point for the horizontal writing-modes. If vertical writing-modes are supported, then each glyph must have another width value, alignment-baseline and alignment-point for the vertical writing-modes. (Even though it is specified as a width, for vertical writing-modes the width is used in the vertical direction.)

The script to which a glyph belongs determines an alignment-baseline to which the glyph is to be aligned. The position of this baseline in the design space coordinate system determines the default block-progression-direction position of the alignment-point. The inline-progression-direction position of the alignment-point is on the start-edge of the glyph. (These positions are adjusted according to the specifications in [7.13.1 "alignment-adjust"] when an instance of a glyph is used in an inline or block formatting object. The "space-start" and/or the "space-end" properties of the fo:character that maps to the glyph may be adjusted to effect "kerning" with respect to adjacent glyphs.)

In addition to the font characteristics required above, a font may also supply substitution and positioning tables that can be used by a formatter to re-order, combine, and position a sequence of glyphs to make one or more composite glyphs. The combination may be as simple as a ligature, or as complex as an Indic syllable which combines, usually with some re-ordering, multiple consonants and vowel glyphs. See [4.7.2 Line-building].

.8.2 "font-family"

XSL modifications to the Surfing definition:

<string>

The names are syntactically expressed as strings.

NOTE:

See the expression language for a two-argument "system-font" function that returns a characteristic of a system-font. This may be used, instead of the "font" shorthand, to specify the name of a system-font.

.8.3 "font-selection-strategy"

XSL Definition:

There is no XSL mechanism to specify a particular font; instead, a selected font is chosen from the fonts available to the User Agent based on a set of selection criteria. The selection criteria are the following font properties: "font-family", "font-style", "font-variant", "font-weight", "font-stretch", and "font-size", plus, for some formatting objects, one or more characters. These characters are called the contextual characters. The contextual characters can be as few as a single character and as many as the entire character complement of the result tree being processed.

Except for the fo:character formatting object, for all other formatting objects where "font-family" applies, the selection criteria consist of the above font properties only. For the fo:character formatting object, the selection criteria are these properties plus either the value of the "character" property of the fo:character alone or that character together with other contextual characters.

The strategy to be followed for selecting a font based on these criteria is specified by the "font-selection-strategy" property.

The "font-family" property is a prioritized list of font family names, which are tried in sequence to find an available font that matches the selection criteria. The font property selection criteria are matched if the corresponding font characteristics match the properties as specified in the property descriptions.

If no matching font is found, a fallback selection is determined in a system-dependent manner.

If no match has been found for a particular character, there is no selected font and the User Agent should provide a visual indication that a character is not being displayed (for example, using the 'missing character' glyph).

Values of the "font-selection-strategy" property have the following meanings:

auto

The selection criterion given by the contextual characters is used in an implementation defined manner.

NOTE:

An implementation may, for example, use an algorithm where all characters in the result tree having the same set of font selection property values influence the selection, or it may only use the character property of a single fo:character formatting object for which a font is to be selected. Consider, for example, a case where the available fonts include a font that covers all of Latin, Greek and Cyrillic as well as three better quality fonts that cover those three separately, but match each other badly stylistically. An implementation that takes a larger view for its set of contextual characters may consider the glyph complement to allow the selection of the better font if it covers the glyph complement, but to use the broader font to get a consistent style if the glyph complement is larger than any one of the other fonts can cover.

character-by-character

The set of contextual characters consists of the single character that is the value of the "character" property of the fo:character for which a font is to be selected.

NOTE:

This selection strategy is the same as the strategy used to select fonts in CSS.

Describes the criteria for selecting fonts and the different strategies for using these criteria to determine a selected font.

.8.4 "font-size"

XSL modifications to the Surfing definition:

XSL incorporates the following text from Surf Clothing 15.5 (http://www.w3.org/TR/REC-CSS2/fonts.html#algorithm) as part of the property definition.

'font-size' must be matched within a UA-dependent margin of tolerance. (Typically, sizes for scalable fonts are rounded to the nearest whole pixel, while the tolerance for bitmapped fonts could be as large as 20%.) Further computations, e.g., by 'em' values in other properties, are based on the computed 'font-size' value.

.8.5 "font-stretch"

.8.6 "font-size-adjust"

.8.7 "font-style"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

backslant

Specifies a font that is classified as "backslant" in the UA's font database.

XSL incorporates the following text from Surf Clothing 15.5 (http://www.w3.org/TR/REC-CSS2/fonts.html#algorithm) as part of the property definition, except that for XSL the information is obtained from the font tables of the available fonts.

'italic' will be satisfied if there is either a face in the UA's font database labeled with the Surfing keyword 'italic' (preferred) or 'oblique'. Otherwise the values must be matched exactly or font-style will fail.

.8.8 "font-variant"

XSL modifications to the Surfing definition:

XSL incorporates the following text from Surf Clothing 15.5 (http://www.w3.org/TR/REC-CSS2/fonts.html#algorithm) as part of the property definition.

'normal' matches a font not labeled as 'small-caps'; 'small-caps' matches (1) a font labeled as 'small-caps', (2) a font in which the small caps are synthesized, or (3) a font where all lowercase letters are replaced by uppercase letters. A small-caps font may be synthesized by electronically scaling uppercase letters from a normal font.

.8.9 "font-weight"

XSL modifications to the Surfing definition:

XSL incorporates the following text from Surf Clothing 15.5.1 (http://www.w3.org/TR/REC-CSS2/fonts.html#q46) as part of the property definition.

The association of other weights within a family to the numerical weight values is intended only to preserve the ordering of weights within that family. User agents must map names to values in a way that preserves visual order; a face mapped to a value must not be lighter than faces mapped to lower values. There is no guarantee on how a user agent will map fonts within a family to weight values. However, the following heuristics tell how the assignment is done in typical cases: If the font family already uses a numerical scale with nine values (as e.g., OpenType does), the font weights should be mapped directly.

If there is both a face labeled Medium and one labeled Book, Regular, Roman or Normal, then the Medium is normally assigned to the '500'.

The font labeled "Bold" will often correspond to the weight value '700'.

If there are fewer then 9 weights in the family, the default algorithm for filling the "holes" is as follows. If '500' is unassigned, it will be assigned the same font as '400'. If any of the values '600', '700', '800', or '900' remains unassigned, they are assigned to the same face as the next darker assigned keyword, if any, or the next lighter one otherwise. If any of '300', '200', or '100' remains unassigned, it is assigned to the next lighter assigned keyword, if any, or the next darker otherwise.

There is no guarantee that there will be a darker face for each of the 'font-weight' values; for example, some fonts may have only a normal and a bold face, others may have eight different face weights.

.9 Common Hyphenation Properties

.9.1 "country"

XSL Definition:

Values have the following meanings:

none

Indicates the country is unknown or is not significant to the proper formatting of this object.

<country>

A country-specifier in conformance with [RFC3066].

Specifies the country to be used by the formatter in language-/locale-coupled services, such as line-justification strategy, line-breaking, and hyphenation.

The country may be the country component of any RFC 3066 code; (these are derived from ISO 3166).

.9.2 "language"

XSL Definition:

Values have the following meanings:

none

Indicates the language is unknown or is not significant to the proper formatting of this object.

<language>

A language-specifier in conformance with [RFC3066].

Specifies the language to be used by the formatter in language-/locale-coupled services, such as line-justification strategy, line-breaking, and hyphenation.

The language may be the language component of any RFC 3066 code (these are derived from the ISO 639 language codes).

.9.3 "script"

XSL Definition:

Values have the following meanings:

auto

Indicates that the script is determined based on testing a character in the document against script identifiers assigned to Unicode code point ranges.

For fo:character the character tested is given by the "character" property. For other formatting objects the character tested is the first character descendant, as determined by the pre-order traversal of the refined formatting object tree, which has an unambigous script identifier.

NOTE:

This provides the automatic differentiation between Kanji, Katakana, Hiragana, and Romanji used in JIS-4051 and similar services in some other countries/languages.

none

Indicates the script is unknown or is not significant to the proper formatting of this object.

<script>

A script specifier in conformance with [ISO15924].

Specifies the script to be used by the formatter in language-/locale-coupled services, such as line-justification strategy, line-breaking, and hyphenation.

.9.4 "hyphenate"

XSL Definition:

Values have the following meanings:

false

Hyphenation may not be used in the line-breaking algorithm for the text contained in this object.

true

Hyphenation may be used in the line-breaking algorithm for the text contained in this object.

Specifies whether hyphenation is allowed during line-breaking when the formatter is formatting this formatting object.

.9.5 "hyphenation-character"

XSL Definition:

Values have the following meanings:

<character>

Specifies the Unicode character to be presented when a hyphenation break occurs. The styling properties of this character are those inherited from its containing flow object.

.9.6 "hyphenation-push-character-count"

XSL Definition:

Values have the following meanings:

<integer>

If a negative or non-integer value is specified, it will be rounded to the nearest integer greater than zero.

The hyphenation-push-character-count is a positive integer specifying the minimum number of characters in a hyphenated word after the hyphenation character. This is the minimum number of characters in the word pushed to the next line after the line ending with the hyphenation character.

.9.7 "hyphenation-remain-character-count"

XSL Definition:

Values have the following meanings:

<integer>

If a negative or non-integer value is specified, it will be rounded to the nearest integer greater than zero.

The hyphenation-remain-character-count is a positive integer specifying the minimum number of characters in a hyphenated word before the hyphenation character. This is the minimum number of characters in the word left on the line ending with the hyphenation character.

.10 Common Margin Properties-Block

.10.1 "margin-top"

XSL modifications to the Surfing definition:

• Margin-top is provided for compatibility with CSS.

• Details on the mapping of Surfing "margin" properties for XSL are given in [5 Property Refinement / Resolution].

.10.2 "margin-bottom"

XSL modifications to the Surfing definition:

• Margin-bottom is provided for compatibility with CSS.

• Details on the mapping of Surfing "margin" properties for XSL are given in [5 Property Refinement / Resolution].

.10.3 "margin-left"

XSL modifications to the Surfing definition:

• Margin-left is provided for compatibility with CSS.

• Details on the mapping of Surfing "margin" properties for XSL are given in [5 Property Refinement / Resolution].

.10.4 "margin-right"

XSL modifications to the Surfing definition:

• Margin-right is provided for compatibility with CSS.

• Details on the mapping of Surfing "margin" properties for XSL are given in [5 Property Refinement / Resolution].

.10.5 "space-before"

XSL Definition:

Values have the following meanings:

<space>

Specifies the minimum, optimum, and maximum values for the space before any areas generated by this formatting object and the conditionality and precedence of this space.

Specifies the value of the space-specifier for the space before the areas generated by this formatting object. A definition of space-specifiers, and the interaction between space-specifiers occurring in sequence are given in [4.3 Spaces and Conditionality].

.10.6 "space-after"

XSL Definition:

Values have the following meanings:

<space>

Specifies the minimum, optimum, and maximum values for the space after any areas generated by this formatting object and the conditionality and precedence of this space.

Specifies the value of the space-specifier for the space after the areas generated by this formatting object. A definition of space-specifiers, and the interaction between space-specifiers occurring in sequence are given in [4.3 Spaces and Conditionality].

.10.7 "start-indent"

XSL Definition:

Values have the following meanings:

<length>

The "start-indent" is specified as a length.

<percentage>

The "start-indent" is specified as a percentage of the inline-progression-dimension of the containing reference-area.

For each block-area generated by this formatting object, specifies the distance from the start-edge of the content-rectangle of the containing reference-area to the start-edge of the content-rectangle of that block-area.

This property may have a negative value, which indicates an outdent.

.10.8 "end-indent"

XSL Definition:

Values have the following meanings:

<length>

The "end-indent" is specified as a length.

<percentage>

The "end-indent" is specified as a percentage of the inline-progression-dimension of the containing reference-area.

For each block-area generated by this formatting object, specifies the distance from the end-edge of the content-rectangle of that block-area to the end-edge of the content-rectangle of the containing reference-area.

This property may have a negative value, which indicates an outdent.

.11 Common Margin Properties-Inline

This group also includes all the properties in the common-margin-properties-block group except space-before, space-after, start-indent, and end-indent.

.11.1 "space-end"

XSL Definition:

Values have the following meanings:

<space>

The "space-end" is specified as a space.

<percentage>

The "space-end" is specified as a percentage of the inline-progression-dimension of the closest ancestor block-area.

Specifies the minimum, optimum, and maximum values for the space after any areas generated by this formatting object and the conditionality and precedence of this space.

Specifies the value of the space-specifier for the space after the areas generated by this formatting object. A definition of space-specifiers, and the interaction between space-specifiers occurring in sequence are given in [4.3 Spaces and Conditionality].

.11.2 "space-start"

XSL Definition:

Values have the following meanings:

<space>

The "space-start" is specified as a space.

<percentage>

The "space-start" is specified as a percentage of the inline-progression-dimension of the closest ancestor block-area.

Specifies the minimum, optimum, and maximum values for the space before any areas generated by this formatting object and the conditionality and precedence of this space.

Specifies the value of the space-specifier for the space before the areas generated by this formatting object. A definition of space-specifiers, and the interaction between space-specifiers occurring in sequence are given in [4.3 Spaces and Conditionality].

.12 Common Relative Position Properties

This group also includes the top, right, bottom, and left properties from the common-absolute-position-properties group.

.12.1 "relative-position"

.13 Area Alignment Properties

The area alignment properties control the alignment of child areas with respect to their parent areas. The parent area is given a frame of clothing through its scaled-baseline-table. A scaled-baseline-table is a compound value with three components: a baseline-identifier for the dominant-baseline, a derived baseline-table with positions for the baselines expressed in design space coordinates, and a baseline-table font-size that is used to scale the positions of the baselines in that baseline table. In a scaled-baseline-table, the positions of the baselines can be adjusted by multiplying the design-space coordinate values by the baseline-table font-size.

The positions of these baselines are illustrated in the following figure:

The baseline-identifiers below are used in this specification. Some of these are determined by baseline-tables contained in a font as described in [7.8.1 Fonts and Font Data]. Others are computed from other font characteristics as described below. Whether determined by the font or computed, a derived baseline-table is constructed with positions for each of the baselines below.

alphabetic

This identifies the baseline used by most alphabetic and syllabic scripts. These include, but are not limited to, many Western, Southern Indic, Southeast Asian (non-ideographic) scripts.

ideographic

This identifies the baseline used by ideographic scripts. For historical reasons, this baseline is at the bottom of the ideographic em box and not in the center of the ideographic em box. See the "central" baseline. The ideographic scripts include Chinese, Japanese, Korean, and Vietnamese Chu Nom.

hanging

This identifies the baseline used by certain Indic scripts. These scripts include Devanagari, Gurmukhi and Bengali.

mathematical

This identifies the baseline used by mathematical symbols.

central

This identifies a computed baseline that is at the center of the em box. This baseline lies halfway between the text-before-edge and text-after-edge baselines.

NOTE:

For ideographic fonts, this baseline is often used to align the glyphs; it is an alternative to the ideographic baseline.

middle

This identifies a baseline that is offset from the alphabetic baseline in the shift-direction by 1/2 the value of the x-height font characteristic. The position of this baseline may be obtained from the font data or, for fonts that have a font characteristic for "x-height", it may be computed using 1/2 the "x-height". Lacking either of these pieces of information, the position of this baseline may be approximated by the "central" baseline.

text-before-edge

This identifies the before-edge of the em box. The position of this baseline may be specified in the baseline-table or it may be calculated.

NOTE:

The position of this baseline is normally around or at the top of the ascenders, but it may not encompass all accents that can appear above a glyph. For these fonts the value of the "ascent" font characteristic is used. For ideographic fonts, the position of this baseline is normally 1 em in the shift-direction from the "ideographic" baseline. However, some ideographic fonts have a reduced width in the inline-progression-direction to allow tighter setting. When such a font, designed only for vertical writing-modes, is used in a horizontal writing-mode, the "text-before-edge" baseline may be less than 1 em from the text-after-edge.

text-after-edge

This identifies the after-edge of the em box. The position of this baseline may be specified in the baseline-table or it may be calculated.

NOTE:

For fonts with descenders, the position of this baseline is normally around or at the bottom of the descenders. For these fonts the value of the "descent" font characteristic is used. For ideographic fonts, the position of this baseline is normally at the "ideographic" baseline.

There are, in addition, two computed baselines that are only defined for line areas. For each line-area, there is a dominant-baseline, a baseline-table and a baseline-table font-size which are those of the nearest ancestor formatting object that completely contains the whole line. The "before-edge" and "after-edge" baselines are defined as follows.

before-edge

The offset of the "before-edge" baseline of the line from the dominant-baseline of the line is determined by ignoring all inline-areas whose alignment-baseline is either "before-edge" or "after-edge". For the "before-edge", extents are measured from the dominant-baseline in the direction toward the top of the reference-area. The top of the reference-area is defined by the reference-area's reference-orientation. The "before-edge" baseline offset is set to the maximum extent of the "before-edges" of the allocation-rectangles of the remaining areas. If all the inline-areas in a line-area are aligned either to the "before-edge" or to the "after-edge", then use the offset of the "text-before-edge" baseline of the line as the offset of the "before-edge" baseline of the line.

after-edge

The offset of the "after-edge" baseline of the line from the dominant-baseline of the line is determined by ignoring all inline-areas whose alignment-baseline is after-edge. For the "after-edge", extents are measured from the dominant-baseline in the direction toward the bottom of the reference-area. The top of the reference-area is defined by the reference-area's reference-orientation. The "after-edge" baseline offset is set to the negative of the maximum of (1) the maximum extent of the "after-edges" of the allocation-rectangles of the remaining areas and (2) the maximum height of the allocation-rectangles of the areas that are ignored minus the offset of the "before-edge" baseline of the line.

NOTE:

If all the inline-areas in a line-area are aligned to the "after-edge" then the specification for the "before-edge" will set the "before-edge" baseline to coincide with the "text-before-baseline" of the line. Then, case (2) above will determine the offset to the "after-edge" baseline. In this case the allocation-rectangle of one of the areas will extend from the "before-edge" baseline to the "after-edge" baseline.

NOTE:

The above specifications for "before-edge" and "after-edge" have the following three properties: (1) the allocation-rectangles of all the areas are below the "before-edge", (2) the allocation-rectangles of all the areas are above the "after-edge", and (3) the distance between the "before-edge" and the "after-edge" cannot be decreased without violating (1) or (2). The specified placement of the "before-edge" and "after-edge" is not the only way that (1)-(3) can be satisfied, but it is the only way they can be satisfied with the smallest possible offset to the "before-edge".

Examples showing "before-edge" and "after-edge" alignment:

There are also four baselines that are defined only for horizontal writing-modes.

top

This baseline is the same as the "before-edge" baseline in a horizontal writing-mode and is undefined in a vertical writing mode.

text-top

This baseline is the same as the "text-before-edge" baseline in a horizontal writing-mode and is undefined in a vertical writing mode.

bottom

This baseline is the same as the "after-edge" baseline in a horizontal writing-mode and is undefined in a vertical writing mode.

text-bottom

This baseline is the same as the "text-after-edge" baseline in a horizontal writing-mode and is undefined in a vertical writing mode.

The alignment of a formatting object with respect to its parent is determined by three things: the scaled-baseline-table of the parent and the alignment-baseline and alignment-point of the formatting object being aligned. Prior to alignment, the scaled-baseline-table of the parent may be shifted. The property specifications below provide the information necessary to align the parent and child formatting objects.

There are four properties that control alignment of formatting objects to the above set of baselines. These properties are all independent and are designed so that typically only the specification of one of the properties is needed to achieve a particular alignment goal.

The primary baseline alignment property is the "dominant-baseline" property. This property has a compound value with three components. The dominant-baseline-identifier component is the default alignment-baseline to be used when aligning two inline-areas. The baseline-table component specifies the positions of the baselines in the font design space coordinates. (See [7.8.1 Fonts and Font Data].) The baseline-table acts something like a musical staff; it defines particular points along the block-progression-direction to which glyphs and inline formatting objects can be aligned. The baseline-table font-size component provides a scaling factor for the baseline-table.

For convenience, the specification will sometimes refer to the baseline identified by the dominant-baseline-identifier component of the "dominant-baseline" property as the "dominant baseline" (in an abuse of terminology).

A simple example of alignment is shown in the following figure. The figure shows the presentation of two inline formatting objects, one inside the other. These inline formatting objects make up the content of a line in a block where the writing-mode is "lr-tb" and the font is "Helvetica". The structure of the example is as follows:

<fo:inline>Apex <fo:inline>Top</fo:inline></fo:inline>

Because no properties are specified, the initial values apply. Since a horizontal writing-mode is in use, the dominant-baseline-identifier is set to "alphabetic" and the baseline-table is taken from the nominal-font for the block in which the line appears, which, in this case, is Helvetica.

In the figure, the positions of the baselines relative to the current font size are shown as red (staff) lines. These lines are labeled with abbreviations of the names of the baselines (e.g., TBE for "text-before-edge"). The baseline identified by the dominant-baseline-identifier (A) is shown in blue. There is a break in the staff lines to separately show the inner inline formatting object. This is not necessary for this example, but this distinction will become important in subsequent examples.

The "alignment-baseline" property is the primary control on the positioning of an inner formatting object with respect to its parent. For all but fo:character, the initial value of the "alignment-baseline" property is "baseline". This aligns the dominant-baseline of the inner inline formatting object with the dominant baseline of the outer inline formatting object. This is shown by the short blue line that connects the two separated staffs (A) in the figure.

The glyphs determined by the fo:characters that are in the content of the two formatting objects are aligned based on the script to which the glyph belongs. Since this example only has Latin glyphs, they are aligned to the "alphabetic" baseline.

In the next figure, the content of the inner inline formatting object is in Gurmukhi, the script of the Punjabi language. The Gurmukhi syllables are read as, "guru". Rather than use Unicode values for these characters, they are symbolized by placing the Latin transliteration in italic type. The structure of the example becomes:

<fo:inline>Apex <fo:inline>guru</fo:inline></fo:inline>

The only change from the previous example is that the glyphs of the Gurmukhi script are aligned to the "hanging" baseline of the inner inline formatting object. The alignment of that formatting object itself, with respect to the outer inline formatting object, is unchanged.

In the next figure, fragments of the text of the previous examples make up the content of the outer inline formatting object. The inner inline formatting object has a change of font-size, however. The structure is:

<fo:inline>Apguru
 <fo:inline font-size='.75em'>
 Exji
 </fo:inline>
</fo:inline>

In this example, the alignment of the inner inline formatting object itself does not change, nor does the alignment of the smaller glyphs inside the inner formatting object. The Latin glyphs are still aligned to the "alphabetic" baseline and the Gurmukhi glyphs, which are pronounced "ji" are aligned to the "hanging" baseline. Note also that just changing the "font-size" property did not change the baseline-table in effect in the inner inline formatting object.

The next figure is equivalent to the previous example with the Gurmukhi character replaced by ideographic characters. These are aligned to the "ideographic" baseline.

To change the scaling of the lines of the baseline table, it is necessary to use the "dominant-baseline" property on the inner inline formatting object. The value of "reset-size" causes the baseline-table font-size to be reset from the font-size of the formatting object on which the "dominant-baseline" property appears. The next figure shows the effect of this, using the structure:

<fo:inline>Apguru
 <fo:inline font-size='.75em'
 dominant-baseline='reset-size'>
 Exji
 </fo:inline>
</fo:inline>

The alignment of the inner inline formatting object, with respect to the outer inline formatting object, is still determined by aligning the dominant baselines. But, the baseline-table of the inner inline formatting object has been rescaled to the font-size of the inner inline formatting object. Hence the smaller glyphs align with each other.

But, what if it is more important that the small Gurmukhi glyphs align with the large Gurmukhi glyphs than having the Latin glyphs align. There are at least two ways to achieve this. The structure:

<fo:inline dominant-baseline='hanging'>Apguru
 <fo:inline font-size='.75em'
 dominant-baseline='reset-size'>
 Exji
 </fo:inline>
</fo:inline>

is illustrated in the next figure. The "hanging" baseline becomes the dominant baseline and the initial value of the "alignment-baseline" property causes the (newly) dominant "hanging" baselines to be aligned as is shown by the connection of the blue baselines.

It is also possible to achieve the effect of the above figure without changing the dominant baseline. Instead it is sufficient to explicitly specify that the inner inline formatting object is aligned on its "hanging" baseline. This is done by:

<fo:inline>Apguru
 <fo:inline font-size='.75em'
 dominant-baseline='reset-size'
 alignment-baseline='hanging'>
 Exji
 </fo:inline>
</fo:inline>

The only change this approach would make in the above figure is to color the "hanging" baseline red and keep the "alphabetic" baseline as the (blue) dominant baseline. This baseline in the inner inline formatting object would not (as it does not in the above figure) align with the "alphabetic" baseline in the outer inline formatting object.

The third baseline alignment property is the "baseline-shift" property. Like the properties other than the "dominant-baseline" property, this property does not change the baseline-table or the baseline-table font-size. It does shift the whole baseline table of the parent formatting object so that when an inner inline formatting object is aligned to one of the parents baselines, the position of the inner inline formatting object is shifted. This is illustrated in the next figure. The structure which creates this figure is:

<fo:inline>Ap
 <fo:inline baseline-shift='super'>1ji</fo:inline>
</fo:inline>

Because the whole set of baseline-table staff lines are shifted to the position of the superscript baseline: it does not matter to which baseline the glyphs in the superscript are aligned. The European number "1" is aligned to the "alphabetic" baseline and the Gurmukhi syllable "ji" is aligned to the "hanging" baseline.

It is more common for the font-size of the superscript text to be smaller than the font-size of the text to which it is appended. Consider:

<fo:inline>Ap
 <fo:inline font-size='.75em'
 baseline-shift='super'>
 1ji
 </fo:inline>
</fo:inline>

Because changing the font-size on a superscript (or subscript) is common, this is the one case where changing the font-size does cause the baseline-table font-size to be reset when the "dominant-baseline" property has its initial value. After the rescaling, the default alignment to the dominant baseline positions the inline formatting object for the superscript to the dominant baseline position in the shifted baseline-table of the parent formatting object.

The fourth alignment property is the "alignment-adjust" property. This property is primarily used for objects, such as some graphics, that do not belong to a particular script and do not have a predefined alignment point. The "alignment-adjust" property allows the author to assign where, on the start-edge of the object, the alignment point for that object lies.

.13.1 "alignment-adjust"

XSL Definition:

The "alignment-adjust" property allows more precise alignment of areas generated by formatting objects, in particular for formatting objects, such as graphics, that do not have a baseline-table or lack the desired baseline in their baseline-table. With the "alignment-adjust" property, the position of the baseline identified by the "alignment-baseline" can be explicitly determined.

Values for the property have the following meaning:

auto

For a glyph, the alignment-point is the intersection of the start-edge of the allocation-rectangle of the glyph-area and the block-progression-direction position of the alignment-point from the font as specified in [7.8.1 Fonts and Font Data]. For other inline-areas, the alignment-point is at the intersection of the start-edge of the allocation-rectangle and the baseline identified by the "alignment-baseline" property if this baseline exists in the baseline-table for the dominant-baseline for the inline-area. If the baseline-identifier does not exist in the baseline-table for the glyph or other inline-area, then the User Agent may either use heuristics to determine where that missing baseline would be or may use the dominant-baseline as a fallback. For areas generated by a fo:external-graphic, or fo:instream-foreign-object, the alignment point is at the intersection of the start-edge and after-edge of the allocation-rectangle of the area.

baseline

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the dominant-baseline of the area.

before-edge

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "before-edge" baseline of the area.

text-before-edge

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "text-before-edge" baseline of the area.

central

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "central" baseline of the area.

middle

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "middle" baseline of the area.

after-edge

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "after-edge" baseline of the area.

text-after-edge

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "text-after-edge" baseline of the area.

ideographic

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "ideographic" baseline of the area.

alphabetic

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "alphabetic" baseline of the area.

hanging

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "hanging" baseline of the area.

mathematical

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "mathematical" baseline of the area.

top

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "top" baseline of the area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

bottom

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "bottom" baseline of the area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

text-top

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "text-top" baseline of the area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

text-bottom

The alignment-point is at the intersection of the start-edge of the allocation-rectangle and the "text-bottom" baseline of the area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

<percentage>

The computed value of the property is this percentage multiplied by the area's computed "height" if the area is generated by an fo:external-graphic or fo:instream-foreign-object, the "font-size" if the area was generated by an fo:character, and the "line-height" otherwise. The alignment-point is on the start-edge of the allocation-rectangle of the area being aligned. Its position along the start-edge relative to the intersection of the dominant-baseline and the start-edge is offset by the computed value. The offset is opposite to the shift-direction if that value is positive and in the shift-direction if that value is negative value). A value of "0%" makes the dominant-baseline the alignment point.

<length>

The alignment-point is on the start-edge of the allocation-rectangle of the area being aligned. Its position along the start-edge relative to the intersection of the dominant-baseline and the start-edge is offset by <length> value. The offset is opposite to the shift-direction if that value is positive and in the shift-direction if that value is negative. A value of "0cm" makes the dominant-baseline the alignment point.

Implementations must support at least one of the "alignment-adjust" values defined in this Recommendation.

.13.2 "alignment-baseline"

XSL Definition:

This property specifies how an object is aligned with respect to its parent. That is, to which of the parent's baselines the alignment-point of this object is aligned. The alignment-adjust property specifies how the alignment point is determined. It defaults to the baseline with the same name as the computed value of the alignment-baseline property. That is, the position of "ideographic" alignment-point in the block-progression-direction is the position of the "ideographic" baseline in the baseline-table of the object being aligned.

Values have the following meanings:

auto

The computed value depends on the kind of object on which it is being used. For fo:character, the value is the dominant-baseline of the script to which the character belongs. If the value of the "script" property on the parent formatting object is other than "auto" then use the baseline for that script; otherwise, use the dominant-baseline of the parent. For all other objects, the value is computed as for the "baseline" value.

baseline

The alignment-point of the object being aligned is aligned with the dominant-baseline of the parent area.

before-edge

The alignment-point of the object being aligned is aligned with the "before-edge" baseline of the parent area.

text-before-edge

The alignment-point of the object being aligned is aligned with the "text-before-edge" baseline of the parent area.

central

The alignment-point of the object being aligned is aligned with the "central" baseline of the parent area.

middle

The alignment-point of the object being aligned is aligned with the "middle" baseline of the parent area.

after-edge

The alignment-point of the object being aligned is aligned with the "after-edge" baseline of the parent area.

text-after-edge

The alignment-point of the object being aligned is aligned with the "text-after-edge" baseline of the parent area.

ideographic

The alignment-point of the object being aligned is aligned with the "ideographic" baseline of the parent area.

alphabetic

The alignment-point of the object being aligned is aligned with the "alphabetic" baseline of the parent area.

hanging

The alignment-point of the object being aligned is aligned with the "hanging" baseline of the parent area.

mathematical

The alignment-point of the object being aligned is aligned with the "mathematical" baseline of the parent area.

top

The alignment-point of the object being aligned is aligned with the "top" baseline of the parent area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

bottom

The alignment-point of the object being aligned is aligned with the "bottom" baseline of the parent area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

text-top

The alignment-point of the object being aligned is aligned with the "text-top" baseline of the parent area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

text-bottom

The alignment-point of the object being aligned is aligned with the "text-bottom" baseline of the parent area if the writing-mode is horizontal. Otherwise, the dominant-baseline is used.

Implementations must support at least one of the "alignment-baseline" values defined in this Recommendation.

.13.3 "baseline-shift"

XSL Definition:

The "baseline-shift" property allows repositioning of the dominant-baseline relative to the dominant-baseline of the parent area. The shifted object might be a subscript or superscript. Within the shifted object, the whole baseline-table is offset; not just a single baseline. The amount of the shift is determined from information from the parent area, the subscript or superscript offset from the nominal-font of the parent area, percent of the "line-height" of the parent area or an absolute value.

When the value of "baseline-shift" is other than "0", then the baseline-table font-size component of the "dominant-baseline" property is re-computed to use the "font-size" applicable to the formatting object on which the non-zero "baseline-shift" property is specified.

Values for the property have the following meaning:

baseline

There is no baseline shift; the dominant-baseline remains in its original position.

sub

The dominant-baseline is shifted to the default position for subscripts. The offset to this position is determined using the font data for the nominal font. Because in most fonts the subscript position is normally given relative to the "alphabetic" baseline, the User Agent may compute the effective position for subscripts for superscripts when some other baseline is dominant. The suggested computation is to subtract the difference between the position of the dominant baseline and the position of the "alphabetic" baseline from the position of the subscript. The resulting offset is determined by multiplying the effective subscript position by the dominant baseline-table font-size. If there is no applicable font data the User Agent may use heuristics to determine the offset.

super

The dominant-baseline is shifted to the default position for superscripts. The offset to this position is determined using the font data for the nominal font. Because in most fonts the superscript position is normally given relative to the "alphabetic" baseline, the User Agent may compute the effective position for superscripts when some other baseline is dominant. The suggested computation is to subtract the difference between the position of the dominant baseline and the position of the "alphabetic" baseline from the position of the superscript. The resulting offset is determined by multiplying the effective superscript position by the dominant baseline-table font-size. If there is no applicable font data the User Agent may use heuristics to determine the offset.

<percentage>

The computed value of the property is this percentage multiplied by the computed "line-height" of the parent area. The dominant-baseline is shifted in the shift-direction (positive value) or opposite to the shift-direction (negative value) of the parent area by the computed value. A value of "0%" is equivalent to "baseline".

<length>

The dominant-baseline is shifted in the shift-direction (positive value) or opposite to the shift-direction (negative value) of the parent area by the <length> value. A value of "0cm" is equivalent to "baseline".

.13.4 "display-align"

XSL Definition:

This property specifies the alignment, in the block-progression-direction, of the areas that are the children of a reference-area.

Values for the property have the following meaning:

auto

If the "relative-align" property applies to this formatting object the "relative-align" property is used. If not, this value is treated as if "before" had been specified.

before

The before-edge of the allocation-rectangle of the first child area is placed coincident with the before-edge of the content-rectangle of the reference-area.

center

The child areas are placed such that the distance between the before-edge of the allocation-rectangle of the first child area and the before-edge of the content-rectangle of the reference-area is the same as the distance between the after-edge of the allocation-rectangle of the last child area and the after-edge of the content-rectangle of the reference-area.

after

The after-edge of the allocation-rectangle of the last child area is placed coincident with the after-edge of the content-rectangle of the reference-area.

.13.5 "dominant-baseline"

XSL Definition:

The "dominant-baseline" property is used to determine or re-determine a scaled-baseline-table. A scaled-baseline-table is a compound value with three components: a baseline-identifier for the dominant-baseline, a derived baseline-table and a baseline-table font-size. Some values of the property re-determine all three values; other only re-establish the baseline-table font-size. When the initial value, "auto", would give an undesired result, this property can be used to explicitly set the desired scaled-baseline-table.

Values for the property have the following meaning:

auto

If this property occurs on a block-level formatting object, then the computed value depends on the value of the "script" property. There are two cases. If the value of the "script" property is "auto", then, if the "writing-mode" is horizontal, then the baseline-identifier for the dominant baseline is set to be "alphabetic", else if the "writing-mode" is vertical, then the baseline-identifier for the dominant baseline is set to be "central". On the other hand, if the value of the "script" property is anything other than "auto", then the value of the "script" property is used to select the baseline-identifier for the dominant baseline. The mapping from script to baseline-identifier is taken from the nominal font. The derived baseline-table is constructed using the baseline-table in the nominal font that corresponds to the baseline-identifier for the dominant baseline. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

Otherwise, if this property is not on a block-level formatting object, then the baseline-identifier for the dominant baseline, the derived baseline-table, and baseline-table font-size remain the same as those of the parent formatting object. If the computed "baseline-shift" value actually shifts the baseline, then the baseline-table font-size is set to the value of the "font-size" property on the formatting object on which the "dominant-baseline" property occurs, otherwise the baseline-table font-size remains the same as that of the parent formatting object. If there is no parent formatting object, the derived baseline-table is constructed as above for block-level formatting-objects.

use-script

The "script" property is used to select the baseline-identifier for the dominant baseline. The mapping from script to baseline-identifier is taken from the nominal font. The derived baseline-table is constructed using the baseline-table in the nominal font that corresponds to the baseline-identifier for the dominant baseline. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

no-change

The dominant-baseline, the baseline-table, and the baseline-table font-size remain the same as that of the parent formatting object.

reset-size

The dominant-baseline and the baseline-table remain the same, but the baseline-table font-size is changed to the value of the "font-size" property on this formatting object. This re-scales the baseline-table for the current "font-size".

ideographic

The baseline-identifier for the dominant-baseline is set to be "ideographic". The derived baseline-table is constructed using the "ideographic" baseline-table in the nominal font. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

alphabetic

The baseline-identifier for the dominant-baseline is set to be "alphabetic". The derived baseline-table is constructed using the "alphabetic" baseline-table in the nominal font. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

hanging

The baseline-identifier for the dominant-baseline is set to be "hanging". The derived baseline-table is constructed using the "hanging" baseline-table in the nominal font. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

mathematical

The baseline-identifier for the dominant-baseline is set to be "mathematical". The derived baseline-table is constructed using the "mathematical" baseline-table in the nominal font. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

central

The baseline-identifier for the dominant-baseline is set to be "central". The derived baseline-table is constructed from the defined baselines in a baseline-table in the nominal font. That font baseline-table is chosen using the following priority order of baseline-table names: "ideographic", "alphabetic", "hanging", "mathematical". The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

middle

The baseline-identifier for the dominant-baseline is set to be "middle". The derived baseline-table is constructed from the defined baselines in a baseline-table in the nominal font. That font baseline-table is chosen using the following priority order of baseline-table names: "alphabetic", "ideographic", "hanging", "mathematical". The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

text-after-edge

The baseline-identifier for the dominant-baseline is set to be "text-after-edge". The derived baseline-table is constructed from the defined baselines in a baseline-table in the nominal font. The choice of which font baseline-table to use from the baseline-tables in the nominal font is implementation defined. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

NOTE:

Using the following priority order of baseline-table names: "alphabetic", "ideographic", "hanging", "mathematical" is probably a reasonable strategy for determining which font baseline-table to use.

text-before-edge

The baseline-identifier for the dominant-baseline is set to be "text-before-edge". The derived baseline-table is constructed from the defined baselines in a baseline-table in the nominal font. The choice of which baseline-table to use from the baseline-tables in the nominal font is implementation defined. The baseline-table font-size is changed to the value of the "font-size" property on this formatting object.

NOTE:

Using the following priority order of baseline-table names: 'alphabetic', 'ideographic', 'hanging', 'mathematical' is probably a reasonable strategy for determining which font baseline-table to use.

If there is no baseline-table in the nominal font or if the baseline-table lacks an entry for the desired baseline, then the User Agent may use heuristics to determine the position of the desired baseline.

Implementations must support at least one of the "dominant-baseline" values defined in this Recommendation.

.13.6 "relative-align"

XSL Definition:

This property specifies the alignment, in the block-progression-direction, between two or more areas. If the "display-align" property applies to this formatting object and has a value other than "auto" this property is ignored.

Values for the property have the following meaning:

before

For an fo:table-cell: for each row, the first child area of all the cells that start in the row and that have this value is placed such that the before-edge of the content-rectangle is placed at the same distance from the row grid. In addition, at least, one of these first child areas of the cells has to be placed with the before-edge of its allocation-rectangle coincident with the before-edge of the content-rectangle of the table-cell.

For an fo:list-item the before-edge of the first area descendant generated by the fo:list-item-label is placed coincident with the before-edge of the area generated by the fo:list-item. Similarly the before-edge of the first area descendant generated by the fo:list-item-body is placed coincident with the before-edge of the area generated by the fo:list-item.

baseline

For an fo:table-cell: for each row, the first child area of all the cells that start in the row and that have this value is placed such that the dominant-baseline, as specified on the fo:table-row, of the first line is placed at the same distance from the row grid. In addition, at least, one of these first child areas of the cells has to be placed with the before-edge of its allocation-rectangle coincident with the before-edge of the content-rectangle of the table-cell.

NOTE:

That is, for all applicable cells the baseline of all the first lines are all aligned and placed the minimum distance down in the block-progression-direction. It should be noted that the start-edges of the content-rectangles of the cells need not align.

For an fo:list-item the distance between the baseline of the first line-area of the first area descendant generated by the fo:list-item-label is the same as the distance between the baseline of the first line-area of the first area descendant generated by the fo:list-item-body. In addition, at least, one of these first area descendants has to be placed such that the before-edge of its allocation-rectangle is coincident with the before-edge of the content-rectangle of the list-item.

.14 Area Dimension Properties

.14.1 "block-progression-dimension"

.14.2 "content-height"

XSL Definition:

Values have the following meanings:

auto

The content-height should be the intrinsic content-height.

scale-to-fit

A size of the content-height equal to the height of the viewport. This value implies a certain scaling factor to be applied onto the content.

<length>

An absolute size for the content-height. This value implies a certain scaling factor to be applied onto the content.

<percentage>

A percentage representing a scaling factor for the content-height.

Specifies the content-height of some object (e.g., an external graphic). If the value is a percentage, the value of this property is the percentage applied to the intrinsic height.

.14.3 "content-width"

XSL Definition:

Values have the following meanings:

auto

The content-width should be the intrinsic content-width.

scale-to-fit

A size of the content-width equal to the width of the viewport. This value implies a certain scaling factor to be applied onto the content.

<length>

An absolute size for the content-width. This value implies a certain scaling factor to be applied onto the content.

<percentage>

A percentage representing a scaling factor for the content-width.

Specifies the content-width of some object (e.g., an external graphic). If the value is a percentage, the value of this property is the percentage applied to the intrinsic width.

.14.4 "height"

XSL modifications to the Surfing definition:

In XSL, this property is mapped to either "inline-progression-dimension" or "block-progression-dimension", based on the applicable values of the "writing-mode" and "reference-orientation" properties. Details on the mapping are given in [5 Property Refinement / Resolution].

For a discussion of the "height" property in tables see: http://www.w3.org/TR/REC-CSS2/tables.html

.14.5 "inline-progression-dimension"

.14.6 "max-height"

XSL modifications to the Surfing definition:

In XSL, this property is mapped to either "inline-progression-dimension" or "block-progression-dimension", based on the applicable values of the "writing-mode" and "reference-orientation" properties. Details on the mapping are given in [5 Property Refinement / Resolution].

.14.7 "max-width"

XSL modifications to the Surfing definition:

In XSL, this property is mapped to either "inline-progression-dimension" or "block-progression-dimension", based on the applicable values of the "writing-mode" and "reference-orientation" properties. Details on the mapping are given in [5 Property Refinement / Resolution].

.14.8 "min-height"

XSL modifications to the Surfing definition:

In XSL, this property is mapped to either "inline-progression-dimension" or "block-progression-dimension", based on the applicable values of the "writing-mode" and "reference-orientation" properties. Details on the mapping are given in [5 Property Refinement / Resolution].

.14.9 "min-width"

XSL modifications to the Surfing definition:

In XSL, this property is mapped to either "inline-progression-dimension" or "block-progression-dimension", based on the applicable values of the "writing-mode" and "reference-orientation" properties. Details on the mapping are given in [5 Property Refinement / Resolution].

.14.10 "scaling"

XSL Definition:

Values have the following meanings:

uniform

Scaling should preserve the aspect ratio.

non-uniform

Scaling need not preserve the aspect ratio.

Specifies whether scaling needs to preserve the intrinsic aspect ratio.

.14.11 "scaling-method"

XSL Definition:

Values have the following meanings:

auto

The User Agent is free to choose either resampling, integer scaling, or any other scaling method.

integer-pixels

The User Agent should scale the image such that each pixel in the original image is scaled to the nearest integer number of device-pixels that yields an image less-then-or-equal-to the image size derived from the content-height, content-width, and scaling properties.

resample-any-method

The User Agent should resample the supplied image to provide an image that fills the size derived from the content-height, content-width, and scaling properties. The user agent may use any sampling method.

This property is used to indicate a preference in the scaling/sizing tradeoff to be used when formatting bitmapped graphics.

.14.12 "width"

XSL modifications to the Surfing definition:

In XSL, this property is mapped to either "inline-progression-dimension" or "block-progression-dimension", based on the applicable values of the "writing-mode" and "reference-orientation" properties. Details on the mapping are given in [5 Property Refinement / Resolution].

.15 Block and Line-related Properties

.15.1 "hyphenation-keep"

XSL Definition:

Values have the following meanings:

auto

No restriction applies. The word may be hyphenated at the end of any region.

column

Both parts of a hyphenated word shall lie within a single column.

page

Both parts of a hyphenated word shall lie within a single page.

Controls whether hyphenation can be performed on the last line that fits in a given reference-area.

.15.2 "hyphenation-ladder-count"

XSL Definition:

Values have the following meanings:

no-limit

Any number of successive lines may be hyphenated.

<integer>

An integer greater than or equal to 1.

Specifies a limit on the number of successive hyphenated line-areas the formatter may generate in a block-area.

.15.3 "last-line-end-indent"

XSL Definition:

Values have the following meanings:

<length>

The "last-line-end-indent" is specified as a length.

<percentage>

The "last-line-end-indent" is specified as a percentage of the inline-progression-dimension of the closest ancestor block-area.

Specifies an indent to be applied to the last line-area child of the last block-area generated and returned by the formatting object, and to any line-area generated by the formatting object whose following sibling is a block-area that is not a line-area. It is added to the block's end-edge. Positive values indent the edge, negative values outdent the edge.

.15.4 "line-height"

XSL modifications to the Surfing definition:

In XSL the "line-height" property is used in determining the half-leading trait.

XSL adds the following value with the following meaning:

<space>

Specifies the minimum, optimum, and maximum values, the conditionality, and precedence of the "line-height" that is used in determining the half-leading.

Negative values for line-height.minimum, line-height.optimum, and line-height.maximum are invalid and will be interpreted as 0pt.

The line-height.conditionality setting can be used to control the half-leading above the first line or after the last line that is placed in a reference-area.

The line-height.precedence setting can be used to control the merging of the half-leading with other spaces.

If line-height is specified using <length>, <percentage>, or <number>, the formatter shall convert the single value to a space-specifier with the subfields interpreted as follows:

• line-height.minimum: the resultant computed value (as a length) of the <length>, <percentage>, or <number>.

• line-height.optimum: the resultant computed value (as a length) of the <length>, <percentage>, or <number>.

• line-height.maximum: the resultant computed value (as a length) of the <length>, <percentage>, or <number>.

• line-height.precedence: force.

• line-height.conditionality: retain

.15.5 "line-height-shift-adjustment"

XSL Definition:

Values have the following meanings:

consider-shifts

In determining the line-height, include the adjusted top-edge and bottom-edge of any characters that have a baseline-shift.

disregard-shifts

In determining the line-height, include the unshifted top-edge and bottom-edge of any characters that have a baseline-shift.

This property is used to control whether the line-height is adjusted for content that has a baseline-shift.

.15.6 "line-stacking-strategy"

XSL Definition:

Values have the following meanings:

line-height

Uses the per-inline-height-rectangle as described in [4.5 Line-areas].

NOTE:

This matches CSS's line-height and positioning strategy.

font-height

Uses the nominal-requested-line-rectangle as described in [4.5 Line-areas].

max-height

Uses the maximal-line-rectangle as described in [4.5 Line-areas].

Selects the strategy for positioning adjacent lines, relative to each other.

Implementations must support at least the "max-height" and "font-height" values defined in this Recommendation, and may treat "line-height" as if "max-height" had been specified.

.15.7 "linefeed-treatment"

XSL Definition:

Values have the following meanings:

ignore

Specifies that any character flow object whose Unicode code point is U+000A shall be discarded during the refinement process.

preserve

Specifies no special action.

treat-as-space

Specifies that any character flow object whose Unicode code point is U+000A (linefeed) shall be converted during the refinement process into a character flow object whose Unicode code point is U+0020 (space).

treat-as-zero-width-space

Specifies that any character flow object whose Unicode code point is U+000A shall be converted during the refinement process into a character flow object whose Unicode code point is U+200B (zero width space).

NOTE:

The Unicode Standard recommends that the zero width space is considered a valid line-break point and that if two characters with a zero width space in between are placed on the same line they are placed with no space between them and that if they are placed on two lines no additional glyph area, such as for a hyphen, is created at the line-break.

The "linefeed-treatment" property specifies the treatment of linefeeds (character flow objects whose Unicode code point is U+000A) during the refinement process.

.15.8 "white-space-treatment"

XSL Definition:

Values have the following meanings:

ignore

Specifies that any character flow object whose character is classified, before any linefeed-treatment handling is considered, as white space in Surf, except for U+000A (linefeed) characters, shall be discarded during the refinement process.

preserve

Specifies that any character flow object whose character is classified, before any linefeed-treatment handling is considered, as white space in XML, except for U+000A (linefeed) characters, shall be converted during the refinement process into a character flow object whose Unicode code point is U+0020 (space).

ignore-if-before-linefeed

Specifies that any character flow object, except for U+000A (linefeed) characters, whose character is classified, before any linefeed-treatment handling is considered, as white space in Surf (or any sequence of such character flow objects) that immediately precedes a character flow object whose Unicode code point, before any linefeed-treatment handling is considered, is U+000A (linefeed), shall be discarded during the refinement process.

ignore-if-after-linefeed

Specifies that any character flow object, except for U+000A (linefeed) characters, whose character is classified, before any linefeed-treatment handling is considered, as white space in Surf (or any sequence of such character flow objects) that immediately follows a character flow object whose Unicode code point, before any linefeed-treatment handling is considered, is U+000A (linefeed), shall be discarded during the refinement process.

ignore-if-surrounding-linefeed

Specifies that any character flow object, except for U+000A (linefeed) characters, whose character is classified, before any linefeed-treatment handling is considered, as white space in Surf (or any sequence of such character flow objects) that immediately precedes or follows a character flow object whose Unicode code point, before any linefeed-treatment handling is considered, is U+000A (linefeed), shall be discarded during the refinement process.

The "white-space-treatment" property specifies the treatment during the refinement process of character flow objects, except for linefeeds, that are classified as white space in Surf. This includes U+0020 (space) and other white space characters but excludes U+000A (linefeed). Linefeed treatment is determined by the "linefeed-treatment" property.

.15.9 "text-align"

XSL modifications to the Surfing definition:

Values have the following meanings:

start

Specifies that the content is to be aligned on the start-edge in the inline-progression-direction.

center

Specifies that the content is to be centered in the inline-progression-direction.

end

Specifies that the content is to be aligned on the end-edge in the inline-progression-direction.

justify

Specifies that the contents is to be expanded to fill the available width in the inline-progression-direction.

The last (or only) line of any block, and any lines in the block ending in U+000A, will be aligned in accordance with the "text-align-last" property value. If such lines are to be justified specify "text-align-last='justify'".

inside

If the page binding edge is on the start-edge, the alignment will be start. If the binding is the end-edge, the alignment will be end. If neither, use start alignment.

outside

If the page binding edge is on the start-edge, the alignment will be end. If the binding is the end-edge, the alignment will be start. If neither, use end alignment.

left

Interpreted as "text-align='start'".

right

Interpreted as "text-align='end'".

<string>

Specifies a string on which content of cells in a table column will align (see the section, in the Surf Clothing Recommendation, on horizontal alignment in a column for details and an example). This value applies only if the formatting object is a descendant of a table cell. If set on other formatting objects, it will be treated as "start".

This property describes how inline content of a block is aligned. For fo:external-graphic, fo:instream-foreign-object, and fo:table-and-caption it specifies the alignment of other areas as described in the constraint section for these formatting objects.

.15.10 "text-align-last"

XSL Definition:

Values have the following meanings:

relative

If text-align is justify, then the alignment of the last line, and of any line ending in U+000A, will be start. If text-align is not justify, text-align-last will use the value of text-align.

start

Specifies that the content is to be aligned on the start-edge in the inline-progression-direction.

center

Specifies that the contents is to be centered in the inline-progression-direction.

end

Specifies that the content is to be aligned on the end-edge in the inline-progression-direction.

justify

Specifies that the contents is to be expanded to fill the available width in the inline-progression-direction.

inside

If the page binding edge is on the start-edge, the alignment will be start. If the binding is the end-edge, the alignment will be end. If neither, use start-side.

outside

If the page binding edge is on the start-edge, the alignment will be end. If the binding is the end-edge the alignment will be start. If neither, use end alignment.

left

Interpreted as "text-align-last='start'".

right

Interpreted as "text-align-last='end'".

Specifies the alignment of the last line-area child of the last block-area generated and returned by the formatting object, and to any line-area generated by the formatting object whose following sibling is a block-area that is not a line-area, and any lines in the block ending in U+000A.

.15.11 "text-indent"

XSL modifications to the Surfing definition:

The "text-indent" property specifies an adjustment to the start-indent of the first child L of the first block-area generated and returned by the formatting object, provided L is a line-area.

A negative value specifies a hanging indent (outdent) on the first line.

.15.12 "white-space-collapse"

XSL Definition:

Values have the following meanings:

false

Specifies no special action.

true

Specifies, for any character flow object such that:

• its character is classified as white space in Surf, and

• it is not, however, a U+000A (linefeed) character, and

• the immediately preceding flow object is a character flow object with a character classified as white space in Surf or the immediately following flow object is a linefeed,

that flow object shall not generate an area.

The "white-space-collapse" property specifies the treatment of consecutive white space during area tree construction. The overall effect of handling the white-space-treatment and linefeed-treatment properties during refinement and the white-space-collapse property during area tree generation is as follows: after refinement, where some white space characters may have been discarded or turned into space characters, all remaining runs of two or more consecutive spaces are replaced by a single space, then any remaining space immediately adjacent to a remaining linefeed is also discarded.

An implementation is free to use any algorithm to achieve an equivalent effect.

.15.13 "wrap-option"

XSL Definition:

Values have the following meanings:

no-wrap

No line-wrapping will be performed.

In the case when lines are longer than the available width of the content-rectangle, the overflow will be treated in accordance with the "overflow" property specified on the reference-area.

wrap

Line-breaking will occur if the line overflows the available block width. No special markers or other treatment will occur.

Specifies how line-wrapping (line-breaking) of the content of the formatting object is to be handled.

Implementations must support the "no-wrap" value, as defined in this Recommendation, when the value of "linefeed-treatment" is "preserve".

.16 Character Properties

.16.1 "character"

XSL Definition:

Values have the following meanings:

<character>

Specifies the code point of the Unicode character to be presented.

.16.2 "letter-spacing"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<space>

This allows the user to specify a range of adjustments in addition to the default space between characters.

The minimum and maximum values specify the limits of the adjustment.

Default space between characters is defined to be 0pt, i.e., glyph-areas stacked with no extra space between the allocation-rectangles of the glyph-areas. The inline-progression-dimension of the glyph-area is obtained by formatting the fo:character.

For an fo:character that in the Unicode database is classified as "Alphabetic", unless the treat-as-word-space trait has the value "true", the space-start and space-end traits are each set to a value as follows:

• For "normal": .optimum = "the normal spacing for the current font" / 2, .maximum = auto, .minimum = auto, .precedence = force, and .conditionality = discard. A value of auto for a component implies that the limits are User Agent specific.

• For a <length>: .optimum = <length> / 2, .maximum =.optimum, .minimum =.optimum, .precedence = force, and .conditionality = discard.

• For a <space>: a value that is half the value of the "letter-spacing" property for the numeric components and the value for the.precedence and .conditionality components. The initial values for.precedence is "force" and for.conditionality "discard".

The Surfing statement that "Conforming user agents may consider the value of the 'letter-spacing' property to be 'normal'." does not apply in XSL, if the User Agent implements the "Extended" property set.

The algorithm for resolving the adjusted values between word spacing and letter spacing is User Agent dependent.

.16.3 "suppress-at-line-break"

XSL Definition:

This property applies only to fo:character and determines whether the character's representation shall be suppressed when it would occur adjacent to a formatter-generated line break. Multiple characters may be so suppressed.

This property has the following values:

auto

The value of this property is determined by the Unicode value of the object's character property. The character at code point U+0020 is treated as if 'suppress' had been specified. All other characters are treated as if 'retain' had been specified.

This value does not automatically suppress the presentation of the non-breaking-space (U+00A0), the fixed spaces (U+2000 through U+200A), or the ideographic-space (U+3000).

suppress

If the glyph-area generated by the fo:character is first or last in a line-building partition (see section [4.7.2 Line-building]) then it is deleted rather than being placed in the area tree, together with all adjacent areas with a suppress-at-line-break value of suppress. Otherwise it is retained and placed in the area tree.

retain

The glyph-area generated by the fo:character shall be placed in the area tree whether or not it is first or last in a line-building partition.

.16.4 "text-decoration"

XSL modifications to the Surfing definition:

XSL adds the following values with the following meanings:

no-underline

Turns off underlining, if any.

no-overline

Turns off overlining, if any.

no-line-through

Turns off line-through, if any.

no-blink

Turns off blinking, if any.

.16.5 "text-shadow"

.16.6 "text-transform"

XSL modifications to the Surfing definition:

There are severe internationalization issues with the use of this property. It has been retained for Surfing compatibility, but its use is not recommended in XSL.

.16.7 "treat-as-word-space"

XSL Definition:

This property determines if the character shall be treated as a word space or as a normal letter.

This property has the following values:

auto

The value of this property is determined by the Unicode code point for the character.

As the default behavior:

• The characters at code points U+0020 and U+00A0 are treated as if 'true' had been specified. All other characters are treated as if 'false' had been specified.

• This property does not automatically apply word spacing to the fixed spaces (U+2000 through U+200A) or the ideographic-space (U+3000).

• This default behavior can be overridden by information in the font used for formatting the character, which can specify additional characters that may be treated as "word spaces".

true

This inline-progression-dimension of the character shall be adjusted as described in the "word-spacing" property.

false

This character shall not have a word spacing adjustment applied.

.16.8 "word-spacing"

XSL modifications to the Surfing definition:

The following value type has been added for XSL:

<space>

This allows the user to specify a range of adjustments in addition to the default space between words.

The minimum and maximum values specify the limits of the adjustment.

Default space between words is defined to be the inline-progression-dimension of the glyph-area obtained by formatting the current fo:character whose treat-as-word-space trait has the value "true".

For fo:character whose treat-as-word-space trait has the value "true", the space-start and space-end traits are each set to a value as follows:

• For "normal": .optimum = ("the normal inter-word space, as defined by the current font and/or the UA" - "the inline-progression-dimension of the glyph-area obtained by formatting the fo:character") / 2, .maximum =.optimum, .minimum =.optimum, .precedence = force, and .conditionality = discard.

• For a <length>: .optimum = <length> / 2, .maximum =.optimum, .minimum =.optimum, .precedence = force, and .conditionality = discard.

• For a <space>: a value that is half the value of the "word-spacing" property for the numeric components and the value for the.precedence and .conditionality components. The initial values for.precedence is "force" and for.conditionality "discard".

The algorithm for resolving the adjusted values between word spacing and letter spacing is User Agent dependent.

.17 Color-related Properties

.17.1 "color"

XSL modifications to the Surfing definition:

XSL adds an "rgb-icc" function (see [5.10.2 Color Functions]) as a valid value of this property.

.17.2 "color-profile-name"

XSL Definition:

<name>

Specifies the name of a color-profile for internal references.

.17.3 "rendering-intent"

XSL Definition:

"rendering-intent" permits the specification of a color-profile rendering-intent other than the default. "rendering-intent" is applicable primarily to color-profiles corresponding to CMYK color spaces. The different options cause different methods to be used for translating colors to the color gamut of the target rendering device.

Values have the following meanings:

auto

This is the default behavior. The User Agent determines the best intent based on the content type. For image content containing an embedded profile, it shall be assumed that the intent specified within the profile is the desired intent. Otherwise, the user agent shall use the current profile and force the intent, overriding any intent that might be stored in the profile itself.

perceptual

This method, often the preferred choice for images, preserves the relationship between colors. It attempts to maintain relative color values among the pixels as they are mapped to the target device gamut. Sometimes pixel values that were originally within the target device gamut are changed in order to avoid hue shifts and discontinuities and to preserve as much as possible the overall appearance of the scene.

relative-colorimetric

Leaves colors that fall inside the gamut unchanged. This method usually converts out of gamut colors to colors that have the same lightness but fall just inside the gamut.

saturation

Preserves the relative saturation (chroma) values of the original pixels. Out of gamut colors are converted to colors that have the same saturation but fall just inside the gamut.

absolute-colorimetric

Disables white point matching when converting colors. This option is generally not recommended.

.18 Float-related Properties

.18.1 "clear"

XSL modifications to the Surfing definition:

A start-float is defined to mean an area with area-class "xsl-side-float" that was generated by an fo:float with property "float" specified as "left" or "start".

An end-float is defined to mean an area with area-class "xsl-side-float" that was generated by an fo:float with property "float" specified as "right" or "end".

A side-float is defined to mean either a start-float or an end-float.

An area is defined to "clear" a side-float if the before-edge of the area's border-rectangle is positioned to be after the after-edge of the float, or if the area is not a descendant of the side-float's parent reference-area.

A block-level formatting object is defined "to clear" a side-float if the areas generated by the formatting object clear the side-float.

In XSL this property applies to block-level formatting objects and fo:float.

The clear property when applied to an fo:float that generates side-floats does not apply to the fo:float's anchor-area.

Values have the following meanings:

start

Specifies that each area generated by the formatting object must clear every start-float whose parent reference-area is the nearest ancestor reference-area of the generated area, provided the start-float was generated by an fo:float that is before this formatting object, using pre-order traversal order of the formatting tree. Additionally specifies that each area generated by the formatting object must be placed so that the reference-area chain containing the generated area's nearest ancestor reference-area does not contain a later reference-area that is the parent of a start-float generated by an fo:float that is before this formatting object, using pre-order traversal of the formatting tree.

end

Specifies that each area generated by the formatting object must clear every end-float whose parent reference-area is the nearest ancestor reference-area of the generated area, provided the end-float was generated by an fo:float that is before this formatting object, using pre-order traversal order of the formatting tree. Additionally specifies that each area generated by the formatting object must be placed so that the reference-area chain containing the generated area's nearest ancestor reference-area does not contain a later reference-area that is the parent of an end-float generated by an fo:float that is before this formatting object, using pre-order traversal of the formatting tree.

left

Interpreted as "clear='start'".

right

Interpreted as "clear='end'".

both

Specifies that each area generated by the formatting object must clear every side-float whose parent reference-area is the nearest ancestor reference-area of the generated area, provided the side-float was generated by an fo:float that is before this formatting object, using pre-order traversal order of the formatting tree. Additionally specifies that each area generated by the formatting object must be placed so that the reference-area chain containing the generated area's nearest ancestor reference-area does not contain a later reference-area that is the parent of a side-float generated by an fo:float that is before this formatting object, using pre-order traversal of the formatting tree.

none

This property does not impose any constraints.

When a block-level formatting object is constrained by the "clear" property, its space-before property component values may be altered as necessary for each area that it generates, in order to meet the constraint. The alterations are constrained to produce the minimum additional space required to meet the constraint of the "clear" property.

.18.2 "float"

XSL modifications to the Surfing definition:

The following values have been added for XSL: "before", "start", and "end".

In XSL this property applies only to fo:float

Values have the following meanings:

before

Specifies that the block-areas generated by the fo:float shall be with area-class "xsl-before-float", and shall be descendants of a before-float-reference-area generated by a conditional sub-region of a region-body.

start

Specifies that the block-areas generated by the fo:float shall be with area-class "xsl-side-float" and shall be floated toward the start-edge of the clothing area.

end

Specifies that the block-areas returned by the fo:float shall be with area-class "xsl-side-float" and shall be floated toward the end-edge of the clothing area.

left

Interpreted as "float='start'".

right

Interpreted as "float='end'".

none

Specifies that the block-areas generated by the fo:float shall be normal.

This property determines the area-class trait of the block-areas returned by the fo:float, which controls the placement and parent of these block-areas.

.18.3 "intrusion-displace"

XSL Definition:

Values have the following meanings:

auto

For a reference-area, this value is treated as if "block" had been specified. For any other area, this value is treated as if "line" had been specified.

none

Neither line areas nor block areas are displaced (nor have any adjustment to their inline progression dimension) due to the intrusion of the float. The float overlays the area without affecting any of the content of the area, unless the "clear" property has a specified value other than "none".

line

The start and end edges of line areas are displaced just enough so that any intrusions no longer intersects the content rectangle of the line area. For the purposes of this test, the allocation rectangle of the intrusion is used in the intersection. Also, such intersections are done with respect to the line area prior to its adjustment of any "text-indent". This will cause a reduction in the inline progression dimension of the line area.

NOTE:

This is the behavior of floats described in CSS2.

indent

The start edge (and end edge) of each line within the block area on which the property occurs is displaced (a) by at least the same amount it would be displaced by the "line" value of this property and (b) in addition, by an amount that preserves the relative offset of that start edge (or end edge) with respect to the start edge (or end edge) of any other line displaced by any intrusion that cause the current line to be displaced. If there is more than one intrusion that could cause a displacement of the line, the largest such displacement is used.

block

The start edge (and end edge) of the block is displaced by the least amount necessary to insure that (a) the start edge (end edge) of the block does not intersect any of the start intrusions (end intrusions) that overlap that block and (b) the amount by which it is displaced is at least as much as the displacement of the parent area, provided the parent is a block-area which is not a reference-area. An intrusion is said to overlap a block if the there is a line parallel to the inline progression direction that intersects the allocation rectangles of both the block and the intrusion.

This property determines the displacement strategy in the presence of intrusions.

.19 Keeps and Breaks Properties

Page breaks only apply to descendants of the fo:flow formatting object, and not within absolutely positioned areas, or out-of-line areas. In descendants of fo:flow formatting objects, column breaks apply, and a column break in the last (or only) column implies a page break; column breaks in static-content apply except for those in the last (or only) column, which are ignored.

The semantics of keeps and breaks are further described in [4.8 Keeps and Breaks].

.19.1 "break-after"

XSL Definition:

Values for these properties have the following meanings:

auto

No break shall be forced.

NOTE:

Page breaks may occur as determined by the formatter's processing as affected by the "widow", "orphan", "keep-with-next", "keep-with-previous", and "keep-together" properties.

column

Imposes a break-after condition with a context consisting of column-areas.

page

Imposes a break-after condition with a context consisting of page-areas.

even-page

Imposes a break-after condition with a context consisting of even page-areas (a blank page may be generated if necessary).

odd-page

Imposes a break-after condition with a context consisting of odd page-areas (a blank page may be generated if necessary).

Specifies that the first normal area generated by formatting the next formatting object, if any, shall be the first one placed in a particular context (e.g. page-area, column-area)

This property has no effect when it appears on an fo:table-row formatting object in which there is any row spanning occurring that includes both the current fo:table-row and the subsequent one.

.19.2 "break-before"

XSL Definition:

Values have the following meanings:

auto

No break shall be forced.

NOTE:

Page breaks may occur as determined by the formatter's processing as affected by the "widow", "orphan", "keep-with-next", "keep-with-previous", and "keep-together" properties.

column

Imposes a break-before condition with a context consisting of column-areas.

page

Imposes a break-before condition with a context consisting of page-areas.

even-page

Imposes a break-before condition with a context consisting of even page-areas (a blank page may be generated if necessary).

odd-page

Imposes a break-before condition with a context consisting of odd page-areas (a blank page may be generated if necessary).

Specifies that the first area generated by formatting this formatting object shall be the first one placed in a particular context (e.g., page-area, column-area).

This property has no effect when it appears on an fo:table-row formatting object in which there is any row spanning occurring that includes both the current fo:table-row and the previous one.

.19.3 "keep-together"

XSL Definition:

This property imposes keep-together conditions on formatting objects.

The <keep> datatype is composed of three components: within-line, within-column, and within-page. Different components apply to different classes of formatting objects and provide keep conditions relative to different contexts. In the case of the within-line component, the keep context consists of line-areas; for the within-column component, the keep context consists of column-areas; for the within-page component, the keep context consists of page-areas. In the descriptions below, the term "appropriate context" should be interpreted in terms of the previous sentence.

Values of the components have the following meanings:

auto

There are no keep-together conditions imposed by this property.

always

Imposes a keep-together condition with strength "always" in the appropriate context.

<integer>

Imposes a keep-together condition with strength of the given <integer> in the appropriate context.

The semantics of keeps and breaks are further described in [4.8 Keeps and Breaks].

.19.4 "keep-with-next"

XSL Definition:

This property imposes keep-with-next conditions on formatting objects.

The <keep> datatype is composed of three components: within-line, within-column, and within-page. Different components apply to different classes of formatting objects and provide keep conditions relative to different contexts. In the case of the within-line component, the keep context consists of line-areas; for the within-column component, the keep context consists of column-areas; for the within-page component, the keep context consists of page-areas. In the descriptions below, the term "appropriate context" should be interpreted in terms of the previous sentence.

Values of the components have the following meanings:

auto

There are no keep-with-next conditions imposed by this property.

always

Imposes a keep-with-next condition with strength "always" in the appropriate context.

<integer>

Imposes a keep-with-next condition with strength of the given <integer> in the appropriate context.

The semantics of keeps and breaks are further described in [4.8 Keeps and Breaks].

.19.5 "keep-with-previous"

XSL Definition:

This property imposes keep-with-previous conditions on formatting objects.

The <keep> datatype is composed of three components: within-line, within-column, and within-page. Different components apply to different classes of formatting objects and provide keep conditions relative to different contexts. In the case of the within-line component, the keep context consists of line-areas; for the within-column component, the keep context consists of column-areas; for the within-page component, the keep context consists of page-areas. In the descriptions below, the term "appropriate context" should be interpreted in terms of the previous sentence.

Values of the components have the following meanings:

auto

There are no keep-with-previous conditions imposed by this property.

always

Imposes a keep-with-previous condition with strength "always" in the appropriate context.

<integer>

Imposes a keep-with-previous condition with strength of the given <integer> in the appropriate context.

The semantics of keeps and breaks are further described in [4.8 Keeps and Breaks].

.19.6 "orphans"

.19.7 "widows"

XSL modifications to the Surfing definition:

In XSL the "orphans" property specifies the minimum number of line-areas in the first area generated by the formatting object. The "widows" property specifies the minimum number of line-areas in the last area generated by the formatting object.

.20 Layout-related Properties

The following are layout-related properties that are not common to all formatting objects.

.20.1 "clip"

.20.2 "overflow"

XSL modifications to the Surfing definition:

One more value is defined as follows:

error-if-overflow

This value implies the same semantics as the value "hidden" with the additional semantic that an error shall be indicated; implementations may recover by clipping the region.

For print media, implementations must support "auto" and "visible", as defined in this Recommendation. Other values may be treated as if "auto" had been specified.

.20.3 "reference-orientation"

XSL Definition:

Values have the following meanings:

0

The reference-orientation of this reference-area has the same reference-orientation as the containing reference-area.

90

The reference-orientation of this reference-area is rotated 90 degrees counter-clockwise from the reference-orientation of the containing reference-area.

180

The reference-orientation of this reference-area is rotated 180 degrees counter-clockwise from the reference-orientation of the containing reference-area.

270

The reference-orientation of this reference-area is rotated 270 degrees counter-clockwise from the reference-orientation of the containing reference-area.

-90

The reference-orientation of this reference-area is rotated 270 degrees counter-clockwise from the reference-orientation of the containing reference-area.

NOTE:

This is equivalent to specifying "270".

-180

The reference-orientation of this reference-area is rotated 180 degrees counter-clockwise from the reference-orientation of the containing reference-area.

NOTE:

This is equivalent to specifying "180".

-270

The reference-orientation of this reference-area is rotated 90 degrees counter-clockwise from the reference-orientation of the containing reference-area.

NOTE:

This is equivalent to specifying "90".

The reference-orientation specifies the direction for "top" for the content-rectangle of the "reference-area". This is used as the clothing for deriving directions, such as the block-progression-direction, inline-progression-direction, etc. as specified by the "writing-mode" and "direction" properties, and the orientation, placement, and tiling of the background.

The "reference-orientation" property is applied only on formatting objects that establish a reference-area. Each value of "reference-orientation" sets the absolute direction for "top", "left", "bottom", and "right"; which is used by "writing-mode", "direction", and all positioning operations that are referenced to the reference-area or are nested within it.

The reference-orientation trait on an area is indirectly derived from the "reference-orientation" property on the formatting object that generates the area or the formatting object ancestors of that formatting object.

.20.4 "span"

XSL Definition:

Values have the following meanings:

none

This object does not span multiple columns.

all

The areas resulting from this flow object shall span all the columns of a multi-column region.

Specifies if a block-level object should be placed in the current column or should span all columns of a multi-column region.

.21 Leader and Rule Properties

.21.1 "leader-alignment"

XSL Definition:

Values have the following meanings:

none

Leader-pattern has no special alignment.

reference-area

Leader-pattern is aligned as if it began on the current reference-area's content-rectangle start-edge.

page

Leader-pattern is aligned as if it began on the current page's start-edge.

Specifies whether fo:leaders having identical content and property values shall have their patterns aligned with each other, with respect to their common reference-area or page.

For fo:leaders where the "leader-pattern" property is specified as "dot" or as "use-content", this property will be honored.

If the fo:leader is aligned, the start-edge of each cycle of the repeated pattern will be placed on the start-edge of the next cycle in the appropriate pattern-alignment grid.

.21.2 "leader-pattern"

XSL Definition:

Values have the following meanings:

space

Leader is to be filled with blank space.

rule

Leader is to be filled with a rule.

If this choice is selected, the "rule-thickness" and "rule-style" properties are used to set the leader's style.

dots

Leader is to be filled with a repeating sequence of dots. The choice of dot character is dependent on the user agent.

use-content

Leader is to be filled with a repeating pattern as specified by the children of the fo:leader.

Provides the specification of how to fill in the leader.

If the leader is aligned, the start-edge of each cycle of each repeating pattern component will be placed on the start-edge of the next cycle in the pattern-alignment grid.

Implementations must support the "space", "rule", and "dots" values, as defined in this Recommendation. The "use-content" value may be treated as if "space" had been specified.

.21.3 "leader-pattern-width"

XSL Definition:

Values have the following meanings:

use-font-metrics

Use the width of the leader-pattern as determined from its font metrics.

<length>

Sets length for leader-pattern-repeating.

The leader will have an inline-space inserted after each pattern cycle to account for any difference between the width of the pattern as determined by the font metrics and the width specified in this property.

If the length specified is less than the value that would be determined via the use-font-metrics choice, the value of this property is computed as if use-font-metrics choice had been specified.

Specifies the length of each repeat cycle in a repeating leader.

For leaders where the "leader-pattern" property is specified as "dots" or as "use-content", this property will be honored.

.21.4 "leader-length"

XSL Definition:

Values have the following meanings:

<length-range>

leader-length.minimum=sets minimum length for a leader

leader-length.optimum=sets optimum length for a leader

leader-length.maximum=sets maximum length for a leader

Specifies the minimum, optimum, and maximum length of an fo:leader.

This property constrains the length of the leader to be between the minimum and maximum lengths.

leader-length.minimum="0pt"
leader-length.optimum="12pt"
leader-length.maximum="100%"

.21.5 "rule-style"

XSL Definition:

Specifies the style (pattern) of the rule.

This property applies only if the "leader-pattern" property is specified as "rule".

Values have the following meanings:

none

No rule, forces rule-thickness to 0.

dotted

The rule is a series of dots.

dashed

The rule is a series of short line segments.

solid

The rule is a single line segment.

double

The rule is two solid lines. The sum of the two lines and the space between them equals the value of "rule-thickness".

groove

The rule looks as though it were carved into the canvas. (Top/left half of the rule's thickness is the color specified; the other half is white.)

ridge

The opposite of "groove", the rule looks as though it were coming out of the canvas. (Bottom/right half of the rule's thickness is the color specified; the other half is white.)

Implementations must support the "none" and "solid" values, as defined in this Recommendation. Other values may be treated as if "solid" had been specified.

.21.6 "rule-thickness"

XSL Definition: