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<pre class='metadata'>
Title: CSS Text Module Level 3
Shortname: css-text
Level: 3
Status: ED
Work Status: Refining
Group: csswg
ED: https://drafts.csswg.org/css-text-3/
TR: https://www.w3.org/TR/css-text-3/
Previous Version: https://www.w3.org/TR/2018/WD-css-text-3-20181206/
Previous Version: https://www.w3.org/TR/2018/WD-css-text-3-20180920/
Previous Version: https://www.w3.org/TR/2017/WD-css-text-3-20170822/
Previous Version: https://www.w3.org/TR/2013/WD-css-text-3-20131010/
Previous Version: https://www.w3.org/TR/2012/WD-css3-text-20121113/
Issue Tracking: Tracker http://www.w3.org/Style/CSS/Tracker/products/10
Test Suite: http://test.csswg.org/suites/css3-text/nightly-unstable/
Editor: Elika J. Etemad / fantasai, Invited Expert, http://fantasai.inkedblade.net/contact, w3cid 35400
Editor: Koji Ishii, Invited Expert, kojiishi@gluesoft.co.jp, w3cid 45369
Editor: Florian Rivoal, Invited Expert, https://florian.rivoal.net, w3cid 43241
Abstract: This CSS module defines properties for text manipulation and specifies their processing model. It covers line breaking, justification and alignment, white space handling, and text transformation.
At Risk: the ''full-width'' value of 'text-transform'
At Risk: the ''full-size-kana'' value of 'text-transform'
At Risk: the <length> values of the 'tab-size' property
At Risk: the 'text-justify' property
At Risk: the percentage values of 'word-spacing'
At Risk: the 'hanging-punctuation' property
At Risk: the ''line-break/anywhere'' value of the 'line-break' property
Ignored Vars: letter-spacing
Status Text: This publication partially addresses the issues in the <a href="https://drafts.csswg.org/css-text-3/issues-lc-2013">disposition of comments</a> since the <a href="https://www.w3.org/TR/2013/WD-css-text-3-20131010/">October 2013 Last Call Working Draft</a>, and, while a marked improvement over the previous draft, is not considered to be entirely up-to-date at the time of publication. A completed dispostion of comments and corresponding draft will be published once the issues are fully addressed and reviewed by the CSSWG and Internationalization WG.
WPT Path Prefix: /css/css-text/
</pre>
<pre class=link-defaults>
spec:css-display-3; type:property; text:display
spec:css-fonts-4; type:property; text:font-feature-settings
</pre>
<style type="text/css">
img { vertical-align: middle; }
span[lang] { font-size: 125%; line-height: 1; vertical-align: middle;}
/* Bidi & spaces example */
.egbidiwsaA,.egbidiwsbB,.egbidiwsaB,.egbidiwsbC
{ white-space:pre;font-size:80%;font-family:monospace; vertical-align:2px; margin:1px }
.egbidiwsaA { background:lime;padding:2px; }
.egbidiwsbB { border:2px solid blue }
.egbidiwsaB { background:yellow;border:2px dotted white }
.egbidiwsbC { border:2px dotted red }
.hyphens-ex {
border: thin solid black;
display: inline-block;
padding: 4pt;
}
/* Start Letter-spacing Tutorial */
.ls-ex {
font-size: 200%;
margin-left: 1em;
margin-right: 1em;
}
.ls-fixed-width {
width: 10em;
}
.color-box { background: rgb(224, 203, 82); }
.bad { color: red; }
.good { color: green; }
/* End Letter-spacing Tutorial */
.char { border: 1px dotted gray; }
.quarter { font-size: 25%; }
tt[lang="ja"] { font-family: "MS Gothic", "Osaka", monospace }
div.figure table {
margin :auto;
}
.feedback {
background: #FFEECC;
border-color: orange;
}
.feedback:before {
content: "Info Needed";
color: #FF8800;
}
.data .no { color: red; }
.data .ok { color: green; }
.data th em { display: block; font-size: smaller; font-weight: normal; font-style: italic; }
</style>
<h2 id="intro">
Introduction</h2>
<p>This module describes the typesetting controls of CSS;
that is, the features of CSS that control the translation of
source text to formatted, line-wrapped text.
Various CSS properties provide control over
<a href="#transforming">case transformation</a>,
<a href="#white-space">white space collapsing</a>,
<a href="#white-space">text wrapping</a>,
<a href="#line-breaking">line breaking rules</a>
and <a href="#hyphenation">hyphenation</a>,
<a href="#justification">alignment and justification</a>,
<a href="#spacing">spacing</a>,
and <a href="#edge-effects">indentation</a>.
<div class="note">
<p>Note: Font selection is covered in <a href="https://www.w3.org/TR/css-fonts-3/">CSS Fonts Level 3</a> [[CSS-FONTS-3]].
<p>
<span id="decoration"></span>
<span id="text-decoration"></span>
<span id="line-decoration"></span>
<span id="text-decoration-line"></span>
<span id="text-decoration-color"></span>
<span id="text-decoration-style"></span>
<span id="text-decoration-skip"></span>
<span id="text-underline-position"></span>
<span id="emphasis-marks"></span>
<span id="text-emphasis-style"></span>
<span id="text-emphasis-color"></span>
<span id="text-emphasis"></span>
<span id="text-emphasis-position"></span>
<span id="text-shadow"></span>
Features for decorating text,
such as <a href="https://www.w3.org/TR/css-text-decor-3/#line-decoration">underlines</a>,
<a href="https://www.w3.org/TR/css-text-decor-3/#emphasis-marks">emphasis marks</a>,
and <a href="https://www.w3.org/TR/css-text-decor-3/#text-shadow-property">shadows</a>,
(previously part of this module)
are covered in
<a href="https://www.w3.org/TR/css-text-decor-3/">CSS Text Decoration Level 3</a> [[CSS-TEXT-DECOR-3]].
<p><a href="https://www.w3.org/TR/css-writing-modes-3/#text-direction">Bidirectional</a> and
<a href="https://www.w3.org/TR/css-writing-modes-3/#vertical-intro">vertical</a> text
are addressed in
<a href="https://www.w3.org/TR/css-writing-modes-3/">CSS Writing Modes Level 3</a> [[CSS-WRITING-MODES-3]].
</div>
Further information about the typesetting requirements
of various languages and writing systems around the world
can be found in the <a href="https://www.w3.org/International/core/">Internationalization Working Group</a>’s
<a href="https://www.w3.org/TR/typography/">Typography Index</a>.
[[TYPOGRAPHY]]
<h3 id="placement">
Module Interactions</h3>
<p>This module, together with [[CSS-TEXT-DECOR-3]],
replaces and extends the text-level features defined in [[!CSS2]] chapter 16.
<p>In addition to the terms defined below,
other terminology and concepts used in this specification are defined
in [[!CSS2]] and [[!CSS-WRITING-MODES-3]].
<!-- Listing level 4 tests as otherwise bikeshed complains -->
<wpt>
white-space/text-space-collapse-discard-001.xht
white-space/text-space-collapse-preserve-breaks-001.xht
white-space/text-space-trim-trim-inner-001.xht
</wpt>
<h3 id="values">
Values</h3>
This specification follows the <a href="https://www.w3.org/TR/CSS2/about.html#property-defs">CSS property definition conventions</a> from [[!CSS2]].
Value types not defined in this specification are defined in CSS Values & Units [[!CSS-VALUES-3]].
Other CSS modules may expand the definitions of these value types.
In addition to the property-specific values listed in their definitions,
all properties defined in this specification
also accept the <a>CSS-wide keywords</a> keywords as their property value.
For readability they have not been repeated explicitly.
<h3 id="languages">
Languages and Typesetting</h3>
<p><strong class="advisement">
Authors should language-tag their content accurately for the best typographic behavior.
</strong>
<p>The <dfn export>content language</dfn> of an element is the (human) language
the element is declared to be in, according to the rules of the
<a href="https://www.w3.org/TR/CSS2/conform.html#doclanguage">document language</a>.
For example, the rules for determining the <a>content language</a> of an HTML
are <a href="https://html.spec.whatwg.org/multipage/dom.html#language">defined</a> in [[HTML]],
and the rules for determining the <a>content language</a> of an XML element use
are <a href="https://www.w3.org/TR/REC-xml/#sec-lang-tag">defined</a> in [[XML10]].
Note that it is possible for the <a>content language</a> of an element
to be unknown--
e.g. untagged content,
or content in a <a>document language</a> that does not have a language-tagging facility
is considered to have an unknown <a>content language</a>.
Note: Authors can tag content using the global <code>lang</code> attribute in HTML,
the universal <code>xml:lang</code> attribute in XML,
and the HTTP <code>Content-Language</code> header for content served over HTTP.
The [=content language=] an element is declared to be in
also identifies the specific written form of that language used in that element,
known as the <dfn export local-lt="writing system">content writing system</dfn>.
Note: Depending on the [=document language=]'s facilities for identifying the [=content language=],
information about the [=writing system=] may only be carried implicitly.
That is typically the case with the [[BCP47]] language tag used in [[HTML]],
although it can optionally indicate the [=writing system=] explicitly
using a script subtag.
Language and writing system conventions can affect
line breaking, hyphenation, justification, glyph selection,
and many other typographic effects.
<strong>In CSS, language-specific typographic tailorings
are only applied when the <a>content language</a> is known (declared).</strong>
Therefore,
higher quality typography requires authors to communicate to the UA
the correct linguistic context of the text in the document.
More information about language tags and their interpretation,
particularly the use of script tags for atypical language + writing-system combinations,
can be found in [[#script-tagging]].
<h3 id="characters">
Characters and Letters</h3>
<p>The basic unit of typesetting is the <dfn export>character</dfn>.
However, because writing systems are not always as simple as the basic English alphabet,
what a <a>character</a> actually is depends on the context in which the term is used.
For example, in Hangul (the Korean writing system),
each square representation of a syllable
(e.g. <span lang=ko-hang title="Hangul syllable HAN">한</span>=<span lang=ko-Latn>Han</span>)
can be considered a <a>character</a>.
However, the square symbol is really composed of multiple letters each representing a phoneme
(e.g. <span lang=ko-hang title="Hangul letter HIEUH">ㅎ</span>=<span lang=ko-Latn>h</span>,
<span lang=ko-hang title="Hangul letter HIEUH">ㅏ</span>=<span lang=ko-Latn>a</span>,
<span lang=ko-hang title="Hangul letter HIEUH">ㄴ</span>=<span lang=ko-Latn>n</span>)
and these also could each be considered a <a>character</a>.
<p>A basic unit of computer text encoding, for any given encoding,
is also called a <a>character</a>,
and depending on the encoding,
a single encoding <a>character</a> might correspond
to the entire pre-composed syllabic <a>character</a> (e.g. <span lang=ko-hang title="Hangul syllable HAN">한</span>),
to the individual phonemic <a>character</a> (e.g. <span lang=ko-hang title="Hangul letter HIEUH">ㅎ</span>),
or to smaller units such as
a base letterform (e.g. <span lang=ko-hang title="Hangul letter IEUNG">ㅇ</span>)
and any combining marks that vary it (e.g. extra strokes that represent aspiration).
<p>In turn, a single encoding <a>character</a> can be represented in the data stream as one or more bytes;
and in programming environments one byte is sometimes also called a <a>character</a>.
<p>Therefore the term <a>character</a> is fairly ambiguous where technical precision is required.
<p>For text layout, we will refer to the <dfn export lt="typographic character unit|typographic character">typographic character unit</dfn>
as the basic unit of text.
Even within the realm of text layout,
the relevant <a>character</a> unit depends on the operation.
For example, line-breaking and letter-spacing will segment
a sequence of Thai characters that include U+0E33 THAI CHARACTER SARA AM differently;
or the behaviour of a conjunct consonant in a script such as Devanagari
may depend on the font in use.
So the <a>typographic character</a> represents a unit of the writing system—<!--
-->such as a Latin alphabetic letter (including its diacritics),
Hangul syllable,
Chinese ideographic character,
Myanmar syllable cluster—<!--
-->that is indivisible with respect to a particular typographic operation
(line-breaking, first-letter effects, tracking, justification, vertical arrangement, etc.).
<wpt>
word-break/word-break-break-all-007.html
word-break/word-break-break-all-008.html
</wpt>
<a href="http://www.unicode.org/reports/tr29/">Unicode Standard Annex #29: Text Segmentation</a>
defines a unit called the <dfn>grapheme cluster</dfn>
which approximates the <a>typographic character</a>.
A UA must use the <em>extended grapheme cluster</em>
(not <em>legacy grapheme cluster</em>), as defined in [[!UAX29]],
as the basis for its <a>typographic character unit</a>.
However, the UA should tailor the definitions
as required by typographic tradition
since the default rules are not always appropriate or ideal--
and is expected to tailor them differently
depending on the operation as needed.
<p class="note">
Note: The rules for such tailorings are out of scope for CSS.
<!--
however W3C currently maintains a wiki page
where some known tailorings are collected.
-->
<div class="example">
The following are some examples of <a>typographic character unit</a> tailorings
required by standard typesetting practice:
<ul>
<li>
<p>In some scripts such as Myanmar or Devanagari,
the <a>typographic character unit</a> for both justification and line-breaking
is an entire syllable,
which can include more than one [[!UAX29]] <a>grapheme cluster</a>.
<li>
<p>In other scripts such as Thai or Lao,
even though for line-breaking the <a>typographic character</a>
matches Unicode’s default <a>grapheme clusters</a>,
for letter-spacing the relevant unit
is <em>less</em> than a [[!UAX29]] <a>grapheme cluster</a>,
and may require decomposition or other substitutions
before spacing can be inserted.
<p>For instance,
to properly letter-space the Thai word คำ (U+0E04 + U+0E33),
the U+0E33 needs to be decomposed into U+0E4D + U+0E32,
and then the extra letter-space inserted before the U+0E32: คํ า.
<p>A slightly more complex example is น้ำ (U+0E19 + U+0E49 + U+0E33).
In this case, normal Thai shaping will first decompose the U+0E33 into U+0E4D + U+0E32
and then swap the U+0E4D with the U+0E49, giving U+0E19 + U+0E4D + U+0E49 + U+0E32.
As before the extra letter-space is then inserted before the U+0E32: นํ้ า.
<li>
<p>Vertical typesetting [[!CSS-WRITING-MODES-3]] can also require tailoring.
For example, when typesetting ''text-orientation/upright'' text,
Tibetan tsek and shad marks are kept with the preceding grapheme cluster,
rather than treated as an independent <a>typographic character unit</a>.
</ul>
</div>
<p>A <dfn export>typographic letter unit</dfn> or <dfn>letter</dfn> for the purpose of this specification
is a <a>typographic character unit</a> belonging to one of the Letter or Number general
categories in Unicode. [[!UAX44]]
See <a href="#character-properties">Character Properties</a>
for how to determine the Unicode properties of a <a>typographic character unit</a>.
<p>The rendering characteristics of a <a>typographic character unit</a> divided
by an element boundary is undefined.
Ideally each component should be rendered
according to the formatting requirements of its respective element’s properties
while maintaining correct shaping and positioning
of the <a>typographic character unit</a> as a whole.
However, depending on the nature of the formatting differences between its parts
and the capabilities of the font technology in use,
this is not always possible.
Therefore such a <a>typographic character unit</a>
may be rendered as belonging to either side of the boundary,
or as some approximation of belonging to both.
Authors are forewarned that dividing <a>grapheme clusters</a>
by element boundaries may give inconsistent or undesired results.
<h3 id="text-encoding">
Text Processing</h3>
CSS is built on [[UNICODE]].
UAs that support Unicode must adhere to all normative requirements
of the Unicode Core Standard,
except where explicitly overridden by CSS.
UAs that use a different encoding are not explicitly supported by the CSS specifications;
they are, however, expected to fulfill the same text handling requirements
by assuming an appropriate mapping between that encoding and Unicode.
<h2 id="transforming">
Transforming Text</h2>
<h3 id="text-transform-property" oldids="text-transform caps-prop">
Case Transforms: the 'text-transform' property</h3>
<pre class="propdef">
Name: text-transform
Value: none | [capitalize | uppercase | lowercase ] || full-width || full-size-kana
Initial: none
Applies to: <a>inline boxes</a>
Inherited: yes
Canonical order: n/a
Computed value: specified keyword
Animation type: discrete
</pre>
<wpt>
inheritance.html
</wpt>
<p>This property transforms text for styling purposes.
It has no effect on the underlying content,
and must not affect the content of a plain text copy & paste operation.
<wpt>
text-transform/text-transform-copy-paste-001-manual.html
</wpt>
<p>Values have the following meanings:
<dl dfn-for=text-transform dfn-type=value>
<dt><dfn>none</dfn></dt>
<dd>No effects.
<wpt>
text-transform/text-transform-none-001.xht
</wpt>
</dd>
<dt><dfn>capitalize</dfn></dt>
<dd>Puts the first <a>typographic letter unit</a> of each word, if lowercase, in titlecase;
other characters are unaffected.
<wpt>
text-transform/text-transform-capitalize-001.html
text-transform/text-transform-capitalize-003.html
text-transform/text-transform-capitalize-005.html
text-transform/text-transform-capitalize-007.html
text-transform/text-transform-capitalize-009.html
text-transform/text-transform-capitalize-010.html
text-transform/text-transform-capitalize-011.html
text-transform/text-transform-capitalize-014.html
text-transform/text-transform-capitalize-016.html
text-transform/text-transform-capitalize-018.html
text-transform/text-transform-capitalize-020.html
text-transform/text-transform-capitalize-022.html
text-transform/text-transform-capitalize-024.html
text-transform/text-transform-capitalize-026.html
text-transform/text-transform-capitalize-028.html
text-transform/text-transform-capitalize-030.html
text-transform/text-transform-capitalize-031.html
text-transform/text-transform-capitalize-032.xht
</wpt>
</dd>
<dt><dfn>uppercase</dfn></dt>
<dd>Puts all <a>letters</a> in uppercase.
<wpt>
text-transform/text-transform-uppercase-001.xht
text-transform/text-transform-upperlower-001.html
text-transform/text-transform-upperlower-003.html
text-transform/text-transform-upperlower-005.html
text-transform/text-transform-upperlower-007.html
text-transform/text-transform-upperlower-009.html
text-transform/text-transform-upperlower-011.html
text-transform/text-transform-upperlower-015.html
text-transform/text-transform-upperlower-017.html
text-transform/text-transform-upperlower-019.html
text-transform/text-transform-upperlower-021.html
text-transform/text-transform-upperlower-023.html
text-transform/text-transform-upperlower-025.html
text-transform/text-transform-upperlower-027.html
text-transform/text-transform-upperlower-029.html
text-transform/text-transform-upperlower-031.html
text-transform/text-transform-upperlower-101.html
text-transform/text-transform-upperlower-103.html
</wpt>
<dt><dfn>lowercase</dfn></dt>
<dd>Puts all <a>letters</a> in lowercase.
<wpt>
text-transform/text-transform-lowercase-001.xht
text-transform/text-transform-lowercase-002.xht
text-transform/text-transform-upperlower-002.html
text-transform/text-transform-upperlower-004.html
text-transform/text-transform-upperlower-006.html
text-transform/text-transform-upperlower-008.html
text-transform/text-transform-upperlower-010.html
text-transform/text-transform-upperlower-012.html
text-transform/text-transform-upperlower-014.html
text-transform/text-transform-upperlower-016.html
text-transform/text-transform-upperlower-018.html
text-transform/text-transform-upperlower-020.html
text-transform/text-transform-upperlower-022.html
text-transform/text-transform-upperlower-024.html
text-transform/text-transform-upperlower-026.html
text-transform/text-transform-upperlower-028.html
text-transform/text-transform-upperlower-030.html
text-transform/text-transform-upperlower-102.html
text-transform/text-transform-upperlower-104.html
</wpt>
</dd>
<dt><dfn>full-width</dfn></dt>
<dd>Puts all <a>typographic character units</a> in fullwidth form.
If a character does not have a corresponding fullwidth form,
it is left as is.
This value is typically used to typeset Latin letters and digits
as if they were ideographic characters.
<wpt>
text-transform/text-transform-fullwidth-001.xht
text-transform/text-transform-fullwidth-002.xht
text-transform/text-transform-fullwidth-004.xht
text-transform/text-transform-fullwidth-005.xht
</wpt>
<dt><dfn>full-size-kana</dfn></dt>
<dd>Converts all [=small Kana=] characters to the equivalent [=full-size Kana=].
This value is typically used for ruby annotation text,
where authors may want all small Kana to be drawn as large Kana
to compensate for legibility issues at the small font sizes typically used in ruby.
<wpt>
text-transform/text-transform-full-size-kana-001.html
text-transform/text-transform-full-size-kana-002.html
text-transform/text-transform-full-size-kana-003.html
text-transform/text-transform-full-size-kana-004.html
text-transform/text-transform-full-size-kana-005.html
text-transform/text-transform-full-size-kana-006.html
text-transform/text-transform-full-size-kana-007.html
</wpt>
</dl>
<p>For ''capitalize'', what constitutes a “word“ is UA-dependent;
[[!UAX29]] is suggested (but not required)
for determining such word boundaries.
Authors should not expect ''capitalize'' to follow
language-specific titlecasing conventions
(such as skipping articles in English).
Out-of-flow elements and inline element boundaries
must not introduce a 'text-transform' word boundary
and must be ignored when determining such word boundaries.
<wpt>
text-transform/text-transform-capitalize-033.html
</wpt>
<div class="example">
<p>The following example converts the ASCII characters
used in abbreviations in Japanese text to their fullwidth variants
so that they lay out and line break like ideographs:
<pre>abbr:lang(ja) { text-transform: full-width; }</pre>
</div>
<p class="note">
Note: As defined in <a href="#order">Text Processing Order of Operations</a>,
transforming text affects line-breaking and other formatting operations.
<p>
The UA must use the full case mappings for Unicode
characters, including any conditional casing rules, as defined in
Default Case Algorithm section of The Unicode Standard [[!UNICODE]].
If (and only if) the <a>content language</a>
of the element is, according to the rules of the
<a href="https://www.w3.org/TR/CSS2/conform.html#doclanguage">document language</a>,
known,
then any appropriate language-specific rules must be applied as well.
These minimally include, but are not limited to, the language-specific
rules in Unicode's
<a href="http://www.unicode.org/Public/UNIDATA/SpecialCasing.txt">SpecialCasing.txt</a>.
<wpt>
writing-system/writing-system-text-transform-001.html
text-transform/text-transform-tailoring-001.html
text-transform/text-transform-tailoring-002.html
text-transform/text-transform-tailoring-002a.html
text-transform/text-transform-tailoring-003.html
text-transform/text-transform-tailoring-004.html
text-transform/text-transform-tailoring-005.html
text-transform/text-transform-upperlower-032.html
text-transform/text-transform-upperlower-033.html
text-transform/text-transform-upperlower-034.html
text-transform/text-transform-upperlower-035.html
text-transform/text-transform-upperlower-038.html
text-transform/text-transform-upperlower-039.html
text-transform/text-transform-upperlower-040.html
text-transform/text-transform-upperlower-041.html
text-transform/text-transform-upperlower-042.html
text-transform/text-transform-upperlower-043.html
</wpt>
<div class="example">
<p>For example, in Turkish there are two “i”s, one with
a dot—“İ” and “i”— and one
without—“I” and “ı”. Thus the usual
case mappings between “I” and “i” are
replaced with a different set of mappings to their respective
undotted/dotted counterparts, which do not exist in English. This
mapping must only take effect if the <a>content language</a> is Turkish
written in its modern Latin-based <a>writing system</a>
(or another Turkic language that uses Turkish casing rules);
in other languages, the usual mapping of “I”
and “i” is required. This rule is thus conditionally
defined in Unicode's SpecialCasing.txt file.
</div>
<p>The definition of fullwidth and halfwidth forms can be found on the
Unicode consortium web site at [[!UAX11]].
The mapping to fullwidth form is defined by taking code points with
the <code><wide></code> or the <code><narrow></code> tag
in their <code>Decomposition_Mapping</code> in [[!UAX44]].
For the <code><narrow></code> tag,
the mapping is from the code point to the decomposition (minus <code><narrow></code> tag),
and for the <code><wide></code> tag,
the mapping is from the decomposition (minus the <code><wide></code> tag)
back to the original code point.
<wpt>
text-transform/text-transform-fullwidth-001.xht
text-transform/text-transform-fullwidth-002.xht
text-transform/text-transform-fullwidth-004.xht
text-transform/text-transform-fullwidth-005.xht
</wpt>
<p>The mappings for small Kana to full-size Kana are defined in [[#small-kana]].
<p>When multiple values are specified and therefore multiple transformations need to be applied,
they are applied in the following order:
<ol>
<li>''capitalize'', ''upercase'', and ''lowercase''
<li>''full-width''
<li>''full-size-kana''
</ol>
<p>Text transformation happens after <a href="#white-space-rules">white
space processing</a>, which means that ''full-width'' only transforms
U+0020 spaces to U+3000 within <a>preserved</a> white space.
<p class="note">
Note: A future level of CSS may introduce the ability to create custom mapping
tables for less common text transforms, such as by an ''@text-transform''
rule similar to ''@counter-style'' from [[CSS-COUNTER-STYLES-3]].
<h2 id="white-space-property" oldids="white-space-collapsing text-wrap">
White Space and Wrapping: the 'white-space' property</h2>
<pre class="propdef">
Name: white-space
Value: normal | pre | nowrap | pre-wrap | break-spaces | pre-line
Initial: normal
Applies to: <a>inline boxes</a>
Inherited: yes
Canonical order: n/a
Computed value: specified keyword
Animation type: discrete
</pre>
<wpt>
inheritance.html
</wpt>
<wpt pathprefix="/css/CSS2/css1/">
c562-white-sp-000.xht
</wpt>
<wpt pathprefix="/css/CSS2/text/">
white-space-006.xht
white-space-007.xht
white-space-applies-to-001.xht
white-space-mixed-001.xht
white-space-mixed-002.xht
white-space-mixed-003.xht
<!-- manual test
white-space-mixed-004.xht
-->
</wpt>
<p>This property specifies two things:
<ul>
<li>whether and how <a>white space</a> inside the element is collapsed
<li>whether lines may <a>wrap</a> at unforced <a>soft wrap opportunities</a>
</ul>
<p>Values have the following meanings, which must be interpreted
according to
the <a href="#white-space-rules">White Space Processing</a> and
<a href="#line-breaking">Line Breaking</a> rules:</p>
<dl dfn-for=white-space dfn-type=value>
<dt><dfn>normal</dfn></dt>
<dd>This value directs user agents to collapse sequences of <a>white space</a>
into a single character (or <a href="#line-break-transform">in some
cases</a>, no character).
Lines may wrap at allowed <a>soft wrap opportunities</a>,
as determined by the line-breaking rules in effect,
in order to minimize inline-axis overflow.
<wpt pathprefix="/css/CSS2/text/">
white-space-normal-001.xht
white-space-normal-002.xht
white-space-normal-003.xht
white-space-normal-004.xht
white-space-normal-005.xht
white-space-normal-006.xht
white-space-normal-007.xht
white-space-normal-008.xht
white-space-normal-009.xht
</wpt>
<dt><dfn>pre</dfn></dt>
<dd>This value prevents user agents from collapsing sequences of <a>white space</a>.
<a>Segment breaks</a> such as line feeds
are preserved as <a>forced line breaks</a>.
Lines only break at <a>forced line breaks</a>;
content that does not fit within the block container overflows it.
<wpt pathprefix="/css/CSS2/text/">
white-space-pre-001.xht
white-space-pre-002.xht
white-space-pre-005.xht
white-space-pre-006.xht
<!--manual test
white-space-pre-007.xht
-->
</wpt>
<dt><dfn>nowrap</dfn>
<dd>Like ''white-space/normal'', this value collapses <a>white space</a>;
but like ''pre'', it does not allow wrapping.
<wpt pathprefix="/css/CSS2/text/">
white-space-nowrap-001.xht
white-space-nowrap-005.xht
white-space-nowrap-006.xht
</wpt>
<dt><dfn>pre-wrap</dfn></dt>
<dd>Like ''pre'', this value preserves <a>white space</a>;
but like ''white-space/normal'', it allows wrapping.
<wpt>
white-space/pre-wrap-001.html
white-space/pre-wrap-002.html
white-space/pre-wrap-003.html
white-space/pre-wrap-004.html
white-space/pre-wrap-005.html
white-space/pre-wrap-006.html
white-space/pre-wrap-007.html
white-space/pre-wrap-011.html
white-space/pre-wrap-012.html
white-space/pre-wrap-013.html
white-space/pre-wrap-014.html
white-space/textarea-pre-wrap-001.html
white-space/textarea-pre-wrap-002.html
white-space/textarea-pre-wrap-003.html
white-space/textarea-pre-wrap-004.html
white-space/textarea-pre-wrap-005.html
white-space/textarea-pre-wrap-006.html
white-space/textarea-pre-wrap-007.html
white-space/textarea-pre-wrap-011.html
white-space/textarea-pre-wrap-012.html
white-space/textarea-pre-wrap-013.html
white-space/textarea-pre-wrap-014.html
white-space/white-space-pre-wrap-trailing-spaces-001.html
white-space/white-space-pre-wrap-trailing-spaces-002.html
white-space/white-space-pre-wrap-trailing-spaces-003.html
</wpt>
<dt><dfn>break-spaces</dfn></dt>
<dd>The behavior is identical to that of ''white-space/pre-wrap'',
except that:
* Any sequence of <a>preserved</a> white space always takes up space,
including at the end of the line.
* A line breaking opportunity exists after every <a>preserved</a> <a>white space</a> character,
including between white space characters.
<wpt>
overflow-wrap/overflow-wrap-break-word-002.html
overflow-wrap/overflow-wrap-anywhere-002.html
white-space/break-spaces-001.html
white-space/break-spaces-002.html
white-space/textarea-break-spaces-001.html
white-space/textarea-break-spaces-002.html
white-space/tab-stop-threshold-005.html
white-space/tab-stop-threshold-006.html
</wpt>
Such preserved spaces take up space and do not hang,
and thus affect the box's intrinsic sizes
([=min-content size=] and [=max-content size=]).
<wpt>
white-space/white-space-intrinsic-size-001.html
white-space/white-space-intrinsic-size-002.html
</wpt>
<p class="note">Note: This value does not guarantee that there will never be any overflow due to spaces:
for example, if the line length is so short that even a single space does not fit,
overflow is unavoidable.</p>
<dt><dfn>pre-line</dfn></dt>
<dd>Like ''white-space/normal'', this value collapses consecutive spaces and allows wrapping,
but preserves <a>segment breaks</a> in the source as <a>forced line breaks</a>.
<wpt pathprefix="/css/CSS2/text/">
white-space-005.xht
white-space-generated-content-before-001.xht
white-space-processing-004.xht
white-space-processing-010.xht
white-space-processing-017.xht
white-space-processing-021.xht
white-space-processing-024.xht
white-space-processing-027.xht
white-space-processing-028.xht
white-space-processing-029.xht
white-space-processing-030.xht
white-space-processing-035.xht
white-space-processing-036.xht
white-space-processing-045.xht
white-space-processing-053.xht
</wpt>
</dl>
<p>White space that was not removed or collapsed due to white space processing
is called <dfn local-lt="preserved">preserved white space</dfn>.
In general, <a>preserved white space</a> is measured when calculating
the <a>intrinsic sizes</a> of text;
however <a>preserved white space</a>
that would be allowed to <a>hang</a> at the end of the line
(i.e. that preserved by ''pre-wrap'')
is excluded--
that is, considered to <a>hang</a>--
when calculating <a>min-content sizes</a> and any sizes derived thereof.
<p>The following informative table summarizes the behavior of various
'white-space' values:</p>
<table class="data">
<colgroup class="header"></colgroup>
<colgroup span=4></colgroup>
<thead>
<tr>
<th></th>
<th>New Lines</th>
<th>Spaces and Tabs</th>
<th>Text Wrapping</th>
<th>End-of-line spaces</th>
</tr>
</thead>
<tbody>
<tr>
<th>''white-space/normal''</th>
<td>Collapse</td>
<td>Collapse</td>
<td>Wrap</td>
<td>Remove</td>
</tr>
<tr>
<th>''pre''</th>
<td>Preserve</td>
<td>Preserve</td>
<td>No wrap</td>
<td>Preserve</td>
</tr>
<tr>
<th>''nowrap''</th>
<td>Collapse</td>
<td>Collapse</td>
<td>No wrap</td>
<td>Remove</td>
</tr>
<tr>
<th>''pre-wrap''</th>
<td>Preserve</td>
<td>Preserve</td>
<td>Wrap</td>
<td>Hang</td>
</tr>
<tr>
<th>''break-spaces''</th>
<td>Preserve</td>
<td>Preserve</td>
<td>Wrap</td>
<td>Wrap</td>
</tr>
<tr>
<th>''pre-line''</th>
<td>Preserve</td>
<td>Collapse</td>
<td>Wrap</td>
<td>Remove</td>
</tbody>
</table>
<p>See <a href="#white-space-processing">White Space Processing Rules</a>
for details on how white space collapses. An informative summary of
collapsing (''white-space/normal'' and ''nowrap'') is presented below:
<ul>
<li>A sequence of segment breaks and other <a>white space</a> between two
Chinese, Japanese, or Yi characters collapses into nothing.
<li>A zero width space before or after a white space sequence
containing a segment break causes the entire sequence of <a>white space</a>
to collapse into a zero width space.
<li>Otherwise, consecutive <a>white space</a> collapses into a single space.
</ul>
<p>See <a href="#line-breaking">Line Breaking</a>
for details on wrapping behavior.
<h2 id="white-space-processing">
White Space Processing Details</h2>
<p>The source text of a document often contains formatting
that is not relevant to the final rendering: for example,
<a href="http://rhodesmill.org/brandon/2012/one-sentence-per-line/">breaking the source into segments</a>
(lines) for ease of editing
or adding white space characters such as tabs and spaces to indent the source code.
CSS white space processing allows the author to control interpretation of such formatting:
to preserve or collapse it away when rendering the document.
White space processing in CSS interprets white space characters only for rendering:
it has no effect on the underlying document data.
<p>White space processing in CSS is controlled with the 'white-space' property.
<p id="segment-normalization">
CSS does not define document segmentation rules. Segments can be
separated by a particular newline sequence (such as a line feed or
CRLF pair), or delimited by some other mechanism, such as the SGML
<code>RECORD-START</code> and <code>RECORD-END</code> tokens.
For CSS processing, each document language–defined segment break
and each line feed (U+000A)
in the text is treated as a <dfn export>segment break</dfn>,
which is then interpreted for rendering as specified by the 'white-space' property.
<p class="note">Note: A document parser might
not only normalize any <a>segment breaks</a>,
but also collapse other space characters or
otherwise process white space according to markup rules.
Because CSS processing occurs <em>after</em> the parsing stage,
it is not possible to restore these characters for styling.
Therefore, some of the behavior specified below
can be affected by these limitations and
may be user agent dependent.</p>
<p class="note">Note: Anonymous blocks consisting entirely of
<a>collapsible</a> <a>white space</a> are removed from the rendering tree.
Thus any such <a>white space</a> surrounding a block-level element is collapsed away.
See [[CSS2]] section
<a href="https://www.w3.org/TR/CSS2/visuren.html#anonymous">9.2.2.1</a></p>
<p>
Control characters (<a>Unicode category</a> <code>Cc</code>)--
other than tabs (U+0009), line feeds (U+000A),
and sequences that form a <a>segment break</a>--
must be rendered as a visible glyph
which the UA must synthethize if the glyphs found in the font are not visible,
and must be otherwise treated as any other character
of the Other Symbols (<code>So</code>) <a>general category</a> and Common <a lt="Unicode script">script</a>.
The UA may use a glyph provided by a font specifically for the control character,
substitute the glyphs provided for the corresponding symbol in the Control Pictures block,
generate a visual representation of its code point value,
or use some other method to provide an appropriate visible glyph.
As required by [[!UNICODE]],
unsupported <code>Default_ignorable</code> characters must be ignored for rendering.
<wpt>
white-space/control-chars-000.html
white-space/control-chars-001.html
white-space/control-chars-002.html
white-space/control-chars-003.html
white-space/control-chars-004.html
white-space/control-chars-005.html
white-space/control-chars-006.html
white-space/control-chars-007.html
white-space/control-chars-008.html
white-space/control-chars-00B.html
white-space/control-chars-00D.html
white-space/control-chars-00E.html
white-space/control-chars-00F.html
white-space/control-chars-010.html
white-space/control-chars-011.html
white-space/control-chars-012.html
white-space/control-chars-013.html
white-space/control-chars-014.html
white-space/control-chars-015.html
white-space/control-chars-016.html
white-space/control-chars-017.html
white-space/control-chars-018.html
white-space/control-chars-019.html
white-space/control-chars-01A.html
white-space/control-chars-01B.html
white-space/control-chars-01C.html
white-space/control-chars-01D.html
white-space/control-chars-01E.html
white-space/control-chars-01F.html
white-space/control-chars-07F.html
white-space/control-chars-080.html
white-space/control-chars-081.html
white-space/control-chars-082.html
white-space/control-chars-083.html
white-space/control-chars-084.html
white-space/control-chars-085.html
white-space/control-chars-086.html
white-space/control-chars-087.html
white-space/control-chars-088.html
white-space/control-chars-089.html
white-space/control-chars-08A.html
white-space/control-chars-08B.html
white-space/control-chars-08C.html
white-space/control-chars-08D.html
white-space/control-chars-08E.html
white-space/control-chars-08F.html
white-space/control-chars-090.html
white-space/control-chars-091.html
white-space/control-chars-092.html
white-space/control-chars-093.html
white-space/control-chars-094.html
white-space/control-chars-095.html
white-space/control-chars-096.html
white-space/control-chars-097.html
white-space/control-chars-098.html
white-space/control-chars-099.html
white-space/control-chars-09A.html
white-space/control-chars-09B.html
white-space/control-chars-09C.html
white-space/control-chars-09D.html
white-space/control-chars-09E.html
white-space/control-chars-09F.html
</wpt>
<h3 id="white-space-rules">
The White Space Processing Rules</h3>
<p>White space processing in CSS affects only
the <dfn export lt="white space|white space characters| document white space|document white space characters">document white space characters</dfn>:
spaces (U+0020), tabs (U+0009), and <a href="#white-space-processing">segment breaks</a>.
<wpt pathprefix="/css/CSS2/text/">
white-space-normal-003.xht
white-space-normal-004.xht
white-space-normal-005.xht
white-space-normal-006.xht