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<!DOCTYPE html><html lang=en><head>
<meta content="text/html; charset=utf-8" http-equiv=Content-Type>
<title>CSS Inline Layout Module Level 3</title>
<link href=../default.css rel=stylesheet type=text/css>
<link href=../csslogo.ico rel="shortcut icon" type=image/x-icon>
<style>
body {
background: url("https://www.w3.org/StyleSheets/TR/logo-ED") top left no-repeat white;
background-attachment: fixed;
color: black;
font-family: sans-serif;
margin: 0 auto;
max-width: 50em;
padding: 2em 1em 2em 70px;
}
:link { color: #00C; background: transparent }
:visited { color: #609; background: transparent }
a[href]:active { color: #C00; background: transparent }
a[href]:hover { background: #ffa }
a[href] img { border-style: none }
h1, h2, h3, h4, h5, h6 { text-align: left }
h1, h2, h3 { color: #005A9C; }
h1 { font: 170% sans-serif }
h2 { font: 140% sans-serif }
h3 { font: 120% sans-serif }
h4 { font: bold 100% sans-serif }
h5 { font: italic 100% sans-serif }
h6 { font: small-caps 100% sans-serif }
.hide { display: none }
div.head { margin-bottom: 1em }
div.head h1 { margin-top: 2em; clear: both }
div.head table { margin-left: 2em; margin-top: 2em }
p.copyright { font-size: small }
p.copyright small { font-size: small }
pre { margin-left: 2em }
dt { font-weight: bold }
ul.toc, ol.toc {
list-style: none;
}
</style>
<style media=print type=text/css>
img#edge { width: 80%; height: 70%;}
dt.label { display: run-in; }
</style>
</head>
<body class=h-entry>
<div class=head>
<p data-fill-with=logo><a class=logo href=http://www.w3.org/>
<img alt=W3C height=48 src=https://www.w3.org/Icons/w3c_home width=72>
</a>
</p>
<h1 class="p-name no-ref" id=title>CSS Inline Layout Module Level 3</h1>
<h2 class="no-num no-toc no-ref heading settled" id=subtitle><span class=content>Editor’s Draft,
<span class=dt-updated><span class=value-title title=20141211>11 December 2014</span></span></span></h2>
<div data-fill-with=spec-metadata><dl><dt>This version:<dd><a class=u-url href=http://dev.w3.org/csswg/css-inline/>http://dev.w3.org/csswg/css-inline/</a><dt>Latest version:<dd><a href=http://www.w3.org/TR/css-inline/>http://www.w3.org/TR/css-inline/</a><dt>Previous Versions:<dd><a href=http://www.w3.org/TR/2002/WD-css3-linebox-20020515/ rel=previous>http://www.w3.org/TR/2002/WD-css3-linebox-20020515/</a><dt>Feedback:<dd><span><a href="mailto:www-style@w3.org?subject=%5Bcss-inline%5D%20feedback">www-style@w3.org</a> with subject line “<kbd>[css-inline] <var>… message topic …</var></kbd>” (<a href=http://lists.w3.org/Archives/Public/www-style/ rel=discussion>archives</a>)</span><dt>Issue Tracking:<dd><a href=#issues-index>Inline In Spec</a><dt class=editor>Editors:<dd class=editor><div class="p-author h-card vcard"><a class="p-name fn u-email email" href=mailto:dauwhe@gmail.com>Dave Cramer</a> (<span class="p-org org">Hachette Livre</span>)</div><dd class=editor><div class="p-author h-card vcard"><a class="p-name fn u-url url" href=http://fantasai.inkedblade.net/contact>Elika J. Etemad</a> (<span class="p-org org">Invited Expert</span>)</div><dd class=editor><div class="p-author h-card vcard"><a class="p-name fn u-email email" href=mailto:szilles@adobe.com>Steve Zilles</a> (<span class="p-org org">Adobe</span>)</div><dt>Issues list:<dd><span><a href="https://www.w3.org/Bugs/Public/buglist.cgi?query_format=advanced&product=CSS&component=Linebox&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED">CSS3 Line Layout issues in Bugzilla</a></span></dl></div>
<div data-fill-with=warning></div>
<p class=copyright data-fill-with=copyright><a href=http://www.w3.org/Consortium/Legal/ipr-notice#Copyright>Copyright</a> © 2014 <a href=http://www.w3.org/><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a href=http://www.csail.mit.edu/><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>, <a href=http://www.ercim.eu/><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href=http://www.keio.ac.jp/>Keio</a>, <a href=http://ev.buaa.edu.cn/>Beihang</a>), All Rights Reserved. W3C <a href=http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer>liability</a>, <a href=http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks>trademark</a> and <a href=http://www.w3.org/Consortium/Legal/copyright-documents>document use</a> rules apply.
</p>
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc no-ref heading settled" id=abstract><span class=content>Abstract</span></h2>
<div class=p-summary data-fill-with=abstract><p>The CSS formatting model provides for a flow of elements and text inside of a container to be wrapped into lines. The formatting of elements and text within a line, its positioning in the inline progression direction, and the breaking of lines are described in <a data-biblio-type=informative data-link-type=biblio href=#biblio-css3text title=CSS3TEXT>[CSS3TEXT]</a>. This module describes the positioning in the block progression direction both of elements and text within lines and of the lines themselves. This positioning is often relative to a baseline. It also describes special features for formatting of first lines and drop caps. It extends on the model in <a data-biblio-type=informative data-link-type=biblio href=#biblio-css2 title=CSS2>[CSS2]</a>.</p>
<a href=http://www.w3.org/TR/CSS/>CSS</a> is a language for describing the rendering of structured documents
(such as HTML and XML)
on screen, on paper, in speech, etc.</div>
<h2 class="no-num no-toc no-ref heading settled" id=status><span class=content>Status of this document</span></h2>
<div data-fill-with=status><p>
This is a public copy of the editors’ draft.
It is provided for discussion only and may change at any moment.
Its publication here does not imply endorsement of its contents by W3C.
Don’t cite this document other than as work in progress.
<p>
The (<a href=http://lists.w3.org/Archives/Public/www-style/>archived</a>) public mailing list
<a href="mailto:www-style@w3.org?Subject=%5Bcss-inline%5D%20PUT%20SUBJECT%20HERE">www-style@w3.org</a>
(see <a href=http://www.w3.org/Mail/Request>instructions</a>)
is preferred for discussion of this specification.
When sending e-mail,
please put the text “css-inline” in the subject,
preferably like this:
“[css-inline] <em>…summary of comment…</em>”
<p>
This document was produced by the <a href=http://www.w3.org/Style/CSS/members>CSS Working Group</a>
(part of the <a href=http://www.w3.org/Style/>Style Activity</a>).
<p>
This document was produced by a group operating under
the <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/>5 February 2004 W3C Patent Policy</a>.
W3C maintains a <a href=http://www.w3.org/2004/01/pp-impl/32061/status rel=disclosure>public list of any patent disclosures</a>
made in connection with the deliverables of the group;
that page also includes instructions for disclosing a patent.
An individual who has actual knowledge of a patent which the individual believes contains <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential>Essential Claim(s)</a>
must disclose the information in accordance with <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure>section 6 of the W3C Patent Policy</a>.
<p>
This document is governed by the <a href=http://www.w3.org/2014/Process-20140801/>1 August 2014 W3C Process Document</a>.
</div>
<div data-fill-with=at-risk></div>
<h2 class="no-num no-toc no-ref heading settled" id=contents><span class=content>Table of Contents</span></h2>
<div data-fill-with=table-of-contents role=navigation><ul class=toc role=directory><li><a href=#line-height><span class=secno>1</span> <span class=content>Line Heights and Baseline Alignment</span></a><li><a href=#initial-letter-styling><span class=secno>2</span> <span class=content>
Initial Letters</span></a><ul class=toc><li><a href=#initial-letter-intro><span class=secno>2.1</span> <span class=content>
An Introduction to Initial Letters</span></a><ul class=toc><li><a href=#drop-initial><span class=secno>2.1.1</span> <span class=content>
Drop Initial</span></a><li><a href=#sunk-initial><span class=secno>2.1.2</span> <span class=content>
Sunken Initial Letters</span></a><li><a href=#raise-initial><span class=secno>2.1.3</span> <span class=content>
Raised Initial Letters</span></a></ul><li><a href=#selecting-drop-initials><span class=secno>2.2</span> <span class=content>Selecting Initial Letters</span></a><li><a href=#sizing-drop-initials><span class=secno>2.3</span> <span class=content>Creating Initial Letters: the <span class=property data-link-type=propdesc title=initial-letter>initial-letter</span> property</span></a><li><a href=#aligning-initial-letter><span class=secno>2.4</span> <span class=content>Alignment of Initial Letters</span></a><li><a href=#initial-letter-box><span class=secno>2.5</span> <span class=content>
Margins, Borders, and Padding</span></a><li><a href=#initial-letter-indentation><span class=secno>2.6</span> <span class=content>
Indentation and Multi-line Effects</span></a><li><a href=#sizing-initial-letters><span class=secno>2.7</span> <span class=content>Sizing Initial Letters</span></a><li><a href=#initial-letter-exclusions><span class=secno>2.8</span> <span class=content>Space Around Initial Letters</span></a><li><a href=#initial-letter-paragraphs><span class=secno>2.9</span> <span class=content>Clearing Initial Letters</span></a><ul class=toc><li><a href=#raised-sunken-caps><span class=secno>2.9.1</span> <span class=content>Raised and sunken caps</span></a><li><a href=#short-para-initial-letter><span class=secno>2.9.2</span> <span class=content>Short paragraphs with initial letters</span></a><li><a href=#initial-letter-floats><span class=secno>2.9.3</span> <span class=content>
Interaction with floats</span></a></ul></ul><li><a href=#ack><span class=secno></span> <span class=content>Acknowledgments</span></a><li><a href=#conformance><span class=secno></span> <span class=content>
Conformance</span></a><ul class=toc><li><a href=#conventions><span class=secno></span> <span class=content>
Document conventions</span></a><li><a href=#conformance-classes><span class=secno></span> <span class=content>
Conformance classes</span></a><li><a href=#partial><span class=secno></span> <span class=content>
Partial implementations</span></a><li><a href=#experimental><span class=secno></span> <span class=content>
Experimental implementations</span></a><li><a href=#testing><span class=secno></span> <span class=content>
Non-experimental implementations</span></a></ul><li><a href=#references><span class=secno></span> <span class=content>References</span></a><ul class=toc><li><a href=#normative><span class=secno></span> <span class=content>Normative References</span></a><li><a href=#informative><span class=secno></span> <span class=content>Informative References</span></a></ul><li><a href=#index><span class=secno></span> <span class=content>Index</span></a><li><a href=#property-index><span class=secno></span> <span class=content>Property Index</span></a><li><a href=#issues-index><span class=secno></span> <span class=content>Issues Index</span></a></ul></div>
<main>
<h2 class="heading settled" data-level=1 id=line-height><span class=secno>1. </span><span class=content>Line Heights and Baseline Alignment</span><a class=self-link href=#line-height></a></h2>
<p class=issue id=issue-469c7c8c><a class=self-link href=#issue-469c7c8c></a>This section is being rewritten. Refer to <a href=http://www.w3.org/TR/CSS21/visudet.html#line-height>section 10.8</a> of <a data-biblio-type=informative data-link-type=biblio href=#biblio-css21 title=CSS21>[CSS21]</a> for the normative CSS definition or the <a href=http://www.w3.org/TR/2002/WD-css3-linebox-20020515/>2002 Working Draft</a> if you want pretty pictures. (But ignore the old text, half of it’s wrong. We’re not specifying which half, that’s to be determined.)</p>
<h2 class="heading settled" data-level=2 id=initial-letter-styling><span class=secno>2. </span><span class=content>
Initial Letters</span><a class=self-link href=#initial-letter-styling></a></h2>
<p class=issue id=issue-f90429eb><a class=self-link href=#issue-f90429eb></a>The editors would appreciate any examples of drop initials in non-western scripts, especially Arabic and Indic scripts.</p>
<h3 class="heading settled" data-level=2.1 id=initial-letter-intro><span class=secno>2.1. </span><span class=content>
An Introduction to Initial Letters</span><a class=self-link href=#initial-letter-intro></a></h3>
<p>Large, decorative letters have been used to start new sections of text since before the invention of printing. In fact, their use predates lowercase letters entirely.</p>
<h4 class="heading settled" data-level=2.1.1 id=drop-initial><span class=secno>2.1.1. </span><span class=content>
Drop Initial</span><a class=self-link href=#drop-initial></a></h4>
<p>A <dfn data-dfn-type=dfn data-noexport="" id=dropped-initial>dropped initial<a class=self-link href=#dropped-initial></a></dfn> (or “drop cap”) is a larger-than-usual letter at the start of a paragraph, with a baseline at least one line lower than the first baseline of the paragraph. The size of the drop initial is usually indicated by how many lines it occupies. Two- and three-line drop initials are very common.</p>
<figure>
<img alt="3-line drop cap with E Acute" src=Dropcap-E-acute-3line.png width=480>
<p class=caption>Three-line drop initial with E acute. Since the cap-height of the drop initial aligns with the cap-height of the main text, the accent extends above the paragraph.</p>
</figure>
<p>The exact size and position of a drop cap depends on the alignment of its glyph. [TK] Reference points on the drop cap must align precisely with reference points in the text. In Western scripts, the top reference points are the cap height of the initial letter and of the first line of text. The bottom reference points are the alphabetic baseline of the initial letter and the baseline of the Nth line of text. <a href=#f2>Figure 2</a> shows a simple two-line drop cap, with the relevant reference lines marked.</p>
<figure id=f2>
<img alt="drop cap showing alignment" src=Dropcap-lines.png width=600>
<p class=caption>Two-line drop cap showing baselines (green lines), cap-height (red line), and ascender (cyan line).</p>
</figure>
<p>The alignment constraints for drop initials depend on the writing system. In Japanese, the initial letter extends from the <a data-link-type=dfn href=http://dev.w3.org/csswg/css-writing-modes-3/#block-start>block-start</a> edge of the first line to the <a data-link-type=dfn href=http://dev.w3.org/csswg/css-writing-modes-3/#block-end>block-end</a> edge of the Nth line.</p>
<figure>
<img alt="Japanese Vertical Initial" src=Initial-2line-JapaneseVertical六.png width=480>
<p class=caption>Two-line drop initial in vertical writing mode</p>
</figure>
<figure>
<img alt="Diagram of Japanese initial letter in vertical writing mode" src=CJK-Initial.001.png width=480>
<p class=caption>Diagram of Japanese initial letter in vertical writing mode</p>
</figure>
<p class=note role=note>Note: In some cases, the exclusion area for the drop initial is larger than its glyph in order to preserve inline-axis alignment. This effect is out-of-scope for this level. However, extra spacing can still be given using margins.</p>
<h4 class="heading settled" data-level=2.1.2 id=sunk-initial><span class=secno>2.1.2. </span><span class=content>
Sunken Initial Letters</span><a class=self-link href=#sunk-initial></a></h4>
<p>Some styles of drop initials do not align with the first line of text. A <dfn data-dfn-type=dfn data-noexport="" id=sunken-initial>sunken initial<a class=self-link href=#sunken-initial></a></dfn> (or “sunken cap”) both sinks below the first baseline, and extends above the first line of text.</p>
<figure>
<img alt="sunken drop initial" src=SunkenCapA.png width=480>
<p class=caption>Sunken cap. The letter drops two lines, but is the size of a three-line initial letter.</p>
</figure>
<h4 class="heading settled" data-level=2.1.3 id=raise-initial><span class=secno>2.1.3. </span><span class=content>
Raised Initial Letters</span><a class=self-link href=#raise-initial></a></h4>
<p>A <dfn data-dfn-type=dfn data-noexport="" id=raised-initial>raised initial<a class=self-link href=#raised-initial></a></dfn> (often called a “raised cap” or “stick-up cap”) “sinks” to the first text baseline. Unlike simply increasing the font size, which affects the line spacing below it to make room for potential descenders, it does not sink below that.</p>
<figure>
<img alt="raised cap" src=RaisedCap.png width=480>
<p class=caption>Raised cap. The initial letter is the size of a 3-line initial, but does not drop.</p>
</figure>
<h3 class="heading settled" data-level=2.2 id=selecting-drop-initials><span class=secno>2.2. </span><span class=content>Selecting Initial Letters</span><a class=self-link href=#selecting-drop-initials></a></h3>
<p>Initial letters are typically a single letter, which can be selected by the <code>::first-letter</code> pseudo-element, as defined in <a data-biblio-type=informative data-link-type=biblio href=#biblio-select title=SELECT>[SELECT]</a>.</p>
<p>Authors who need more control over which characters are included in an initial letter, or who want to apply initial-letter formatting to replaced elements or multiple words can also apply the <a class=property data-link-type=propdesc href=#propdef-initial-letter>initial-letter</a> property to the first inline-level child of a block container.
<div class=example>
<pre><p>This paragraph has a dropped “T”.
<p><img alt="H" src="illuminated-h.svg">ere we have an illuminated “H”.
<p><span>Words may also</span> be given initial letter styling at the beginning of a paragraph.
</pre>
<pre>::first-letter, /* style first paragraph’s T */
img, /* style illuminated H */
span /* drop Words may also */
{ initial-letter: 2; }
</pre>
</div>
<h3 class="heading settled" data-level=2.3 id=sizing-drop-initials><span class=secno>2.3. </span><span class=content>Creating Initial Letters: the <a class=property data-link-type=propdesc href=#propdef-initial-letter>initial-letter</a> property</span><a class=self-link href=#sizing-drop-initials></a></h3>
<table class="definition propdef"><tr><th>Name:<td><dfn class=css data-dfn-type=property data-export="" id=propdef-initial-letter>initial-letter<a class=self-link href=#propdef-initial-letter></a></dfn><tr><th>Value:<td class=prod>normal <a data-link-for="" data-link-type=grammar href=http://dev.w3.org/csswg/css-values-3/#comb-one>|</a> [<a class="production css" data-link-type=type href=#typedef-integer><integer></a> <a class="production css" data-link-type=type href=#typedef-number><number></a><a data-link-for="" data-link-type=grammar href=http://dev.w3.org/csswg/css-values-3/#mult-opt>?</a>]<tr><th>Initial:<td>normal<tr><th>Applies to:<td><code>::first-letter</code> pseudo-elements and inline-level first child of a block container<tr><th>Inherited:<td>no<tr><th>Percentages:<td>N/A<tr><th>Media:<td>visual<tr><th>Computed value:<td>as specified<tr><th>Animatable:<td>no</table>
<p>This property specifies styling for dropped, raised, and sunken initial letters. It takes the following values:</p>
<dl for=initial-letter>
<dt><dfn data-dfn-type=dfn data-noexport="" id=normal>normal<a class=self-link href=#normal></a></dfn>
<dd>No special initial-letter effect. Text behaves as normal.
<dt><dfn class=css data-dfn-type=type data-export="" id=typedef-number><a class="production css" data-link-type=type href=#typedef-number><number></a><a class=self-link href=#typedef-number></a></dfn>
<dd>This first argument defines the size of the initial letter, in terms of how many lines it occupies. Negative values are not allowed.
<dt><dfn class=css data-dfn-type=type data-export="" id=typedef-integer><a class="production css" data-link-type=type href=#typedef-integer><integer></a><a class=self-link href=#typedef-integer></a></dfn>
<dd>This optional second argument argument defines the number of lines the initial letter should sink. Values must be greater than zero. If omitted, it duplicates the first argument, floored to the nearest positive whole number.
</dl>
<div class=example>
Here are some examples of <a class=property data-link-type=propdesc href=#propdef-initial-letter>initial-letter</a> usage:
<dl>
<dt><a class=css data-link-type=propdesc href=#propdef-initial-letter title=initial-letter>initial-letter: 3</a>
<dt>(<a class=css data-link-type=propdesc href=#propdef-initial-letter title=initial-letter>initial-letter: 3 3</a>)
<dd>Represents a <a data-link-type=dfn href=#dropped-initial>dropped initial</a> 3 lines high, 3 lines deep.
<dt><a class=css data-link-type=propdesc href=#propdef-initial-letter title=initial-letter>initial-letter: 3 2</a>
<dd>Represents a <a data-link-type=dfn href=#sunken-initial>sunken initial</a> 3 lines high, 2 lines deep.
<dt><a class=css data-link-type=propdesc href=#propdef-initial-letter title=initial-letter>initial-letter: 3 1</a>
<dd>Represents a <a data-link-type=dfn href=#raised-initial>raised initial</a> 3 lines high, 1 line deep.
</dl>
<p class=issue id=issue-2e07b898><a class=self-link href=#issue-2e07b898></a>Add pictures.</p>
</div>
<div class=example>
The following code will create a 2-line dropped initial letter at the beginning of each paragraph:
<pre>p::first-letter { initial-letter: 2; }</pre>
</div>
<p class=issue id=issue-664624cd><a class=self-link href=#issue-664624cd></a>Define interaction with Ruby. Easiest is to make it not apply to/within ruby.</p>
<p>The <a class=property data-link-type=propdesc href=#propdef-initial-letter>initial-letter</a> property does not apply to boxes that are not positioned at the start of the line due to bidi reordering.</p>
<h3 class="heading settled" data-level=2.4 id=aligning-initial-letter><span class=secno>2.4. </span><span class=content>Alignment of Initial Letters</span><a class=self-link href=#aligning-initial-letter></a></h3>
<p>As mentioned earlier, the alignment of initial letters depends on the script used. The <a class=property data-link-type=propdesc href=#propdef-initial-letter-align>initial-letter-align</a> property can be used to specify the proper alignment.</p>
<table class="definition propdef"><tr><th>Name:<td><dfn class=css data-dfn-type=property data-export="" id=propdef-initial-letter-align>initial-letter-align<a class=self-link href=#propdef-initial-letter-align></a></dfn><tr><th>Value:<td class=prod>[ auto <a data-link-for="" data-link-type=grammar href=http://dev.w3.org/csswg/css-values-3/#comb-one>|</a> alphabetic <a data-link-for="" data-link-type=grammar href=http://dev.w3.org/csswg/css-values-3/#comb-one>|</a> hanging <a data-link-for="" data-link-type=grammar href=http://dev.w3.org/csswg/css-values-3/#comb-one>|</a> ideographic ]<tr><th>Initial:<td>auto<tr><th>Applies to:<td><code>::first-letter</code> pseudo elements and inline level first child of a block container<tr><th>Inherited:<td>no<tr><th>Percentages:<td>N/A<tr><th>Media:<td>visual<tr><th>Computed value:<td>???<tr><th>Animatable:<td>no</table>
<dl data-dfn-for=initial-letter-align data-dfn-type=value>
<dt>auto</dt>
<dd>The user agent selects the value which corresponds to the language of the text. Western languages would default to <a class=css data-link-type=maybe href=http://dev.w3.org/csswg/css-counter-styles-3/#valdef-counter-style-system-alphabetic>alphabetic</a>, CJK languages to <span class=css>ideographic</span>, and some Indic languages to <a class=css data-link-type=maybe href=http://dev.w3.org/csswg/css-text-3/#valdef-text-indent-hanging>hanging</a>. </dd>
<dt>alphabetic</dt>
<dd>As described above, the cap height of the initial letter aligns with the cap height of the first line of text. The baseline of the initial letter aligns with the baseline of the Nth text baseline.</dd>
<dt>hanging</dt>
<dd>The hanging baseline of the initial letter aligns with the hanging baseline of the first line of text. </dd>
<dt>ideographic</dt>
<dd>The initial letter is centered in the N-line area. </dd>
</dl>
<p class=issue id=issue-209367a3><a class=self-link href=#issue-209367a3></a>Input from those knowledgeable about non-Western typographic traditions would be very helpful in describing the appropriate alignments. More values may be required for this property.</p>
<div class=example>
The vertical writing mode example from <a href=#f2>Figure 2</a> could be coded as:
<pre>span.initial {
initial-letter: 2;
initial-letter-alignment: ideographic;
}
</pre>
</div>
<p>If <a class=property data-link-type=propdesc href=#propdef-initial-letter>initial-letter</a> is applied to an image or other atomic element that does not provide the necessary alignment information, the alignment points for the atomic inline must be synthesized from the content edges.</p>
<p class=note role=note>Note: For <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visudet.html#propdef-vertical-align>vertical-align</a>, the alignment points of an atomic inline are synthesized from the margin edges. <a data-biblio-type=informative data-link-type=biblio href=#biblio-css3-writing-modes title=CSS3-WRITING-MODES>[CSS3-WRITING-MODES]</a></p>
<h3 class="heading settled" data-level=2.5 id=initial-letter-box><span class=secno>2.5. </span><span class=content>
Margins, Borders, and Padding</span><a class=self-link href=#initial-letter-box></a></h3>
<p>Initial letters can be styled with margins, padding, and borders just like any other box. Their vertical alignment and sizing is not affected; however the effective exclusion area is (and corresponds to the margin area).</p>
<p>The inline-axis position of the inline letter is given by aligning its margin edge to the edge of the content box. However, for a non-atomic initial letter with zero padding and borders, there is an additional negative offset so that the first glyph is positioned to the containing block edge as normal. (Note: This requirement is because the start-edge of the glyph’s ink area does not always correspond to the start-edge alignment point, which is often chosen for better optical alignment.)</p>
<h3 class="heading settled" data-level=2.6 id=initial-letter-indentation><span class=secno>2.6. </span><span class=content>
Indentation and Multi-line Effects</span><a class=self-link href=#initial-letter-indentation></a></h3>
<p><a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-text-3/#propdef-text-indent>text-indent</a> and <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-text-3/#propdef-hanging-punctuation>hanging-punctuation</a> apply to the first line of text as normal in the presence of initial letters. Lines affected by the exclusion are shortened, as in the presence of floats, and are affected the same way.</p>
<p>If an initial letter is too long to fit on one line, it wraps (according to the usual text-wrapping rules), each line filled and formatted exactly as if it were the first line and the initial letter too long to fit any subsequent normal text. Any normal text after the initial letter starts on its last line, affected exactly as if that line were the first line.</p>
<h3 class="heading settled" data-level=2.7 id=sizing-initial-letters><span class=secno>2.7. </span><span class=content>Sizing Initial Letters</span><a class=self-link href=#sizing-initial-letters></a></h3>
<p>The size of a drop initial is determined by the need to satisfy the required alignment. For an N-line drop initial in a Western script, the cap-height of the letter needs to be (N – 1) times the line-height, plus the cap-height of the surrounding text. Note this height is <b>not</b> the font size of the drop initial.</p>
<p>Actually calculating this font size is tricky. For an N-line drop initial, we find the drop initial font size to be:</p>
<figure>
<img alt="Equation to calcuate drop initial font size" src=InitialCapEquation.png width=604>
</figure>
<p></p>
<p></p>
<div class=example>
A three-line drop initial in Adobe Minion Pro would have a font size of 61.2pt, given 12pt text, 16pt line-height and a cap-height of 651/1000 (from the font’s OS/2 table).
</div>
<p>The line height used in this calculation is the <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visudet.html#propdef-line-height>line-height</a> of the containing block (or, in the case where a baseline grid is in use, the baseline-to-baseline spacing required by the bas
6C33
eline grid <a data-biblio-type=informative data-link-type=biblio href=#biblio-css3-line-grid title=CSS3-LINE-GRID>[CSS3-LINE-GRID]</a>). The contents of the lines spanned, and therefore any variation in their heights and positions, is not accounted for.</p>
<h3 class="heading settled" data-level=2.8 id=initial-letter-exclusions><span class=secno>2.8. </span><span class=content>Space Around Initial Letters</span><a class=self-link href=#initial-letter-exclusions></a></h3>
<p>The glyph(s) of an initial letter do not always fit within the specified sink. For example, if an initial letter has a descender, it could crash into the (n+1)th line of text. This is not desirable.</p>
<figure>
<img alt="3-line drop cap with J, with descender crashing into fourth line of text" src=Dropcap-J-3line-crash.png width=480>
<p class=caption>Incorrect: three-line initial letter with descender</p>
</figure>
<p>Text is therefore excluded around the glyph bounding boxes of the initial letters.</p>
<p>Specifically, for non-atomic initial letters, the content box of the element is sized to fit:</p>
<ul>
<li>The specified amount of sink (i.e the distance from the top alignment point to the bottom alignment point).
<li>The actual ascent and descent and side bearings of all the glyphs it contains that are part of its inline formatting context, even if they leak outside their em boxes.
<li>The margin boxes of all the atomic inlines it contains that are part of its inline formatting context, even if they leak outside its own line-height.
</ul>
<p>The margin box of the initial letter is then made an exclusion area for subsequent text.</p>
<figure>
<img alt="3-line drop cap with J, but four-line exclusion" src=Dropcap-J-3line-exclude.png width=480>
<p class=caption>Correct: text excluded around glyph bounding box</p>
</figure>
<h3 class="heading settled" data-level=2.9 id=initial-letter-paragraphs><span class=secno>2.9. </span><span class=content>Clearing Initial Letters</span><a class=self-link href=#initial-letter-paragraphs></a></h3>
<h4 class="heading settled" data-level=2.9.1 id=raised-sunken-caps><span class=secno>2.9.1. </span><span class=content>Raised and sunken caps</span><a class=self-link href=#raised-sunken-caps></a></h4>
<p>An initial letter does not affect the position of its containing element. For “raised caps” or “sunken caps,” the effect is created as if the text around the initial letter was pushed down, rather than the letter extending up into previous elements.</p>
<figure>
<img alt="raised cap para after normal para" src=initial-letter-drop-para-compare.png width=600>
<p class=caption>Raised cap (<code>initial-letter: 3 1</code>) on right; note that the position of the “C” is the same in both cases, but on the right all text is moved down relative to the initial letter.</p>
</figure>
<p class=issue id=issue-f77cbeb9><a class=self-link href=#issue-f77cbeb9></a>Handle glyph ink above cap height of font.</p>
<h4 class="heading settled" data-level=2.9.2 id=short-para-initial-letter><span class=secno>2.9.2. </span><span class=content>Short paragraphs with initial letters</span><a class=self-link href=#short-para-initial-letter></a></h4>
<p>A paragraph with an initial letter can have fewer lines of text than the initial letter occupies. In this case, the initial letter’s top alignment is still honored, and its exclusion area continues into any subsequent blocks. This forces the subsequent inline-level content to wrap around the initial letter—exactly as if that block’s text were part of its own containing block. (This is similar to how floats exclude content in subsequent block boxes.)</p>
<figure>
<img alt="short para with initial letter" src=initial-letter-short-para.png width=600>
<p class=caption>The red text is a short paragraph with an initial letter. Note the subsequent paragraph wraps around the initial letter just as text in the paragraph with the initial letter does.</p>
</figure>
<p>If the subsequent block starts with an initial letter,
establishes a new formatting context,
or specifies <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visuren.html#propdef-clear>clear</a> in the initial letter’s containing block’s start direction,
then it must clear the previous block’s initial letter.</p>
<figure>
<img alt="short para with initial letter followed by para with initial" src=initial-letter-short-para-initial.png width=600>
<p class=caption>The red text is a short paragraph with an initial letter. The subsequent paragraph clears because it also has an initial letter.</p>
</figure>
<h4 class="heading settled" data-level=2.9.3 id=initial-letter-floats><span class=secno>2.9.3. </span><span class=content>
Interaction with floats</span><a class=self-link href=#initial-letter-floats></a></h4>
<p>Floats always clear an initial letter when floated to the same side. When floated to the opposite side, they are pushed down to clear the initial letter only if they have specified <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visuren.html#propdef-clear>clear</a> to this side or they do not fit without overlapping the initial letter.</p>
<p class=issue id=issue-2ad0a0cb><a class=self-link href=#issue-2ad0a0cb></a>Is this the behavior we want? What if the float is on the same line as the initial letter?</p>
<h2 class="no-num heading settled" id=ack><span class=content>Acknowledgments</span><a class=self-link href=#ack></a></h2>
<p>Special thanks goes to the initial authors,
Eric A. Meyer and Michel Suignard.
<p>In additions to the authors, this specification would not have been possible without the help from:
<p>David Baron, John Daggett, Stephen Deach, Sujal Parikh, Grzegorz Zygmunt, Chris Wilson, David M Brown, Bobby Tung, Shinyu Murakami, David Hyatt, Sylvain Galineau, Alan Stearns, Ted O’Connor.
</main>
<h2 class="no-ref no-num heading settled" id=conformance><span class=content>
Conformance</span><a class=self-link href=#conformance></a></h2>
<h3 class="no-ref heading settled" id=conventions><span class=content>
Document conventions</span><a class=self-link href=#conventions></a></h3>
<p>Conformance requirements are expressed with a combination of
descriptive assertions and RFC 2119 terminology. The key words "MUST",
"MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in the normative parts of this
document are to be interpreted as described in RFC 2119.
However, for readability, these words do not appear in all uppercase
letters in this specification.
<p>All of the text of this specification is normative except sections
explicitly marked as non-normative, examples, and notes. <a data-biblio-type=normative data-link-type=biblio href=#biblio-rfc2119 title=RFC2119>[RFC2119]</a></p>
<p>Examples in this specification are introduced with the words "for example"
or are set apart from the normative text with <code>class="example"</code>,
like this:
<div class=example>
<p>This is an example of an informative example.</p>
</div>
<p>Informative notes begin with the word "Note" and are set apart from the
normative text with <code>class="note"</code>, like this:
<p class=note role=note>Note, this is an informative note.</p>
<p>Advisements are normative sections styled to evoke special attention and are
set apart from other normative text with <code><strong class="advisement"></code>, like
this:
<strong class=advisement>
UAs MUST provide an accessible alternative.
</strong>
<h3 class="no-ref heading settled" id=conformance-classes><span class=content>
Conformance classes</span><a class=self-link href=#conformance-classes></a></h3>
<p>Conformance to this specification
is defined for three conformance classes:
<dl>
<dt>style sheet
<dd>A <a href=http://www.w3.org/TR/CSS21/conform.html#style-sheet>CSS
style sheet</a>.
<dt>renderer
<dd>A <a href=http://www.w3.org/TR/CSS21/conform.html#user-agent>UA</a>
that interprets the semantics of a style sheet and renders
documents that use them.
<dt>authoring tool
<dd>A <a href=http://www.w3.org/TR/CSS21/conform.html#user-agent>UA</a>
that writes a style sheet.
</dl>
<p>A style sheet is conformant to this specification
if all of its statements that use syntax defined in this module are valid
according to the generic CSS grammar and the individual grammars of each
feature defined in this module.
<p>A renderer is conformant to this specification
if, in addition to interpreting the style sheet as defined by the
appropriate specifications, it supports all the features defined
by this specification by parsing them correctly
and rendering the document accordingly. However, the inability of a
UA to correctly render a document due to limitations of the device
does not make the UA non-conformant. (For example, a UA is not
required to render color on a monochrome monitor.)
<p>An authoring tool is conformant to this specification
if it writes style sheets that are syntactically correct according to the
generic CSS grammar and the individual grammars of each feature in
this module, and meet all other conformance requirements of style sheets
as described in this module.
<h3 class="no-ref heading settled" id=partial><span class=content>
Partial implementations</span><a class=self-link href=#partial></a></h3>
<p>So that authors can exploit the forward-compatible parsing rules to
assign fallback values, CSS renderers <strong>must</strong>
treat as invalid (and <a href=http://www.w3.org/TR/CSS21/conform.html#ignore>ignore
as appropriate</a>) any at-rules, properties, property values, keywords,
and other syntactic constructs for which they have no usable level of
support. In particular, user agents <strong>must not</strong> selectively
ignore unsupported component values and honor supported values in a single
multi-value property declaration: if any value is considered invalid
(as unsupported values must be), CSS requires that the entire declaration
be ignored.</p>
<h3 class="no-ref heading settled" id=experimental><span class=content>
Experimental implementations</span><a class=self-link href=#experimental></a></h3>
<p>To avoid clashes with future CSS features, the CSS2.1 specification
reserves a <a href=http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords>prefixed
syntax</a> for proprietary and experimental extensions to CSS.
<p>Prior to a specification reaching the Candidate Recommendation stage
in the W3C process, all implementations of a CSS feature are considered
experimental. The CSS Working Group recommends that implementations
use a vendor-prefixed syntax for such features, including those in
W3C Working Drafts. This avoids incompatibilities with future changes
in the draft.
</p>
<h3 class="no-ref heading settled" id=testing><span class=content>
Non-experimental implementations</span><a class=self-link href=#testing></a></h3>
<p>Once a specification reaches the Candidate Recommendation stage,
non-experimental implementations are possible, and implementors should
release an unprefixed implementation of any CR-level feature they
can demonstrate to be correctly implemented according to spec.
<p>To establish and maintain the interoperability of CSS across
implementations, the CSS Working Group requests that non-experimental
CSS renderers submit an implementation report (and, if necessary, the
testcases used for that implementation report) to the W3C before
releasing an unprefixed implementation of any CSS features. Testcases
submitted to W3C are subject to review and correction by the CSS
Working Group.
<p>Further information on submitting testcases and implementation reports
can be found from on the CSS Working Group’s website at
<a href=http://www.w3.org/Style/CSS/Test/>http://www.w3.org/Style/CSS/Test/</a>.
Questions should be directed to the
<a href=http://lists.w3.org/Archives/Public/public-css-testsuite>public-css-testsuite@w3.org</a>
mailing list.
<h2 class="no-num heading settled" id=references><span class=content>References</span><a class=self-link href=#references></a></h2><h3 class="no-num heading settled" id=normative><span class=content>Normative References</span><a class=self-link href=#normative></a></h3><dl><dt id=biblio-rfc2119 title=rfc2119><a class=self-link href=#biblio-rfc2119></a>[rfc2119]<dd>S. Bradner. <a href=https://tools.ietf.org/html/rfc2119>Key words for use in RFCs to Indicate Requirement Levels</a>. March 1997. Best Current Practice. URL: <a href=https://tools.ietf.org/html/rfc2119>https://tools.ietf.org/html/rfc2119</a></dl><h3 class="no-num heading settled" id=informative><span class=content>Informative References</span><a class=self-link href=#informative></a></h3><dl><dt id=biblio-css2 title=CSS2><a class=self-link href=#biblio-css2></a>[CSS2]<dd>Bert Bos; et al. <a href=http://www.w3.org/TR/CSS2>Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification</a>. 7 June 2011. REC. URL: <a href=http://www.w3.org/TR/CSS2>http://www.w3.org/TR/CSS2</a><dt id=biblio-css21 title=CSS21><a class=self-link href=#biblio-css21></a>[CSS21]<dd>Bert Bos; et al. <a href=http://www.w3.org/TR/2011/REC-CSS2-20110607>Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification</a>. 7 June 2011. W3C Recommendation. URL: <a href=http://www.w3.org/TR/2011/REC-CSS2-20110607>http://www.w3.org/TR/2011/REC-CSS2-20110607</a><dt id=biblio-css3-line-grid title=CSS3-LINE-GRID><a class=self-link href=#biblio-css3-line-grid></a>[CSS3-LINE-GRID]<dd>Koji Ishii. <a href=http://dev.w3.org/csswg/css-line-grid/>CSS Line Grid Module</a>. Proposal for a CSS module. (Retrieved 26 October 2011) URL: <a href=http://dev.w3.org/csswg/css-line-grid/>http://dev.w3.org/csswg/css-line-grid/</a><dt id=biblio-css3-writing-modes title=CSS3-WRITING-MODES><a class=self-link href=#biblio-css3-writing-modes></a>[CSS3-WRITING-MODES]<dd>Elika J. Etemad; Koji Ishii. <a href=http://www.w3.org/TR/2012/WD-css3-writing-modes-20121115/>CSS Writing Modes Module Level 3</a>. 15 November 2012. W3C Working Draft. (Work in progress.) URL: <a href=http://www.w3.org/TR/2012/WD-css3-writing-modes-20121115/>http://www.w3.org/TR/2012/WD-css3-writing-modes-20121115/</a><dt id=biblio-css3text title=CSS3TEXT><a class=self-link href=#biblio-css3text></a>[CSS3TEXT]<dd>Elika J. Etemad; Koji Ishii. <a href=http://www.w3.org/TR/2012/WD-css3-text-20121113/>CSS Text Module Level 3</a>. 13 November 2012. W3C Working Draft. (Work in progress.) URL: <a href=http://www.w3.org/TR/2012/WD-css3-text-20121113/>http://www.w3.org/TR/2012/WD-css3-text-20121113/</a><dt id=biblio-select title=SELECT><a class=self-link href=#biblio-select></a>[SELECT]<dd>Tantek Çelik; et al. <a href=http://www.w3.org/TR/2011/REC-css3-selectors-20110929/>Selectors Level 3</a>. 29 September 2011. W3C Recommendation. URL: <a href=http://www.w3.org/TR/2011/REC-css3-selectors-20110929/>http://www.w3.org/TR/2011/REC-css3-selectors-20110929/</a></dl><h2 class="no-num heading settled" id=index><span class=content>Index</span><a class=self-link href=#index></a></h2><ul class=indexlist><li>dropped initial, <a href=#dropped-initial title="section 2.1.1">2.1.1</a><li>initial-letter, <a href=#propdef-initial-letter title="section 2.3">2.3</a><li>initial-letter-align, <a href=#propdef-initial-letter-align title="section 2.4">2.4</a><li><integer>, <a href=#typedef-integer title="section 2.3">2.3</a><li>normal, <a href=#normal title="section 2.3">2.3</a><li><number>, <a href=#typedef-number title="section 2.3">2.3</a><li>raised initial, <a href=#raised-initial title="section 2.1.3">2.1.3</a><li>sunken initial, <a href=#sunken-initial title="section 2.1.2">2.1.2</a></ul><h2 class="no-num heading settled" id=property-index><span class=content>Property Index</span><a class=self-link href=#property-index></a></h2><table class="proptable data"><thead><tr><th scope=col>Name<th scope=col>Value<th scope=col>Initial<th scope=col>Applies to<th scope=col>Inh.<th scope=col>%ages<th scope=col>Media<th scope=col>Animatable<th scope=col>Computed value<tbody><tr><th scope=row><a class=css data-link-type=property href=#propdef-initial-letter>initial-letter</a><td>normal | [<integer> <number>?]<td>normal<td>::first-letter pseudo-elements and inline-level first child of a block container<td>no<td>N/A<td>visual<td>no<td>as specified<tr><th scope=row><a class=css data-link-type=property href=#propdef-initial-letter-align>initial-letter-align</a><td>[ auto | alphabetic | hanging | ideographic ]<td>auto<td>::first-letter pseudo elements and inline level first child of a block container<td>no<td>N/A<td>visual<td>no<td>???</table><h2 class="no-num heading settled" id=issues-index><span class=content>Issues Index</span><a class=self-link href=#issues-index></a></h2><div style=counter-reset:issue><div class=issue>This section is being rewritten. Refer to <a href=http://www.w3.org/TR/CSS21/visudet.html#line-height>section 10.8</a> of <a data-biblio-type=informative data-link-type=biblio href=#biblio-css21 title=CSS21>[CSS21]</a> for the normative CSS definition or the <a href=http://www.w3.org/TR/2002/WD-css3-linebox-20020515/>2002 Working Draft</a> if you want pretty pictures. (But ignore the old text, half of it’s wrong. We’re not specifying which half, that’s to be determined.)<a href=#issue-469c7c8c> ↵ </a></div><div class=issue>The editors would appreciate any examples of drop initials in non-western scripts, especially Arabic and Indic scripts.<a href=#issue-f90429eb> ↵ </a></div><div class=issue>Add pictures.<a href=#issue-2e07b898> ↵ </a></div><div class=issue>Define interaction with Ruby. Easiest is to make it not apply to/within ruby.<a href=#issue-664624cd> ↵ </a></div><div class=issue>Input from those knowledgeable about non-Western typographic traditions would be very helpful in describing the appropriate alignments. More values may be required for this property.<a href=#issue-209367a3> ↵ </a></div><div class=issue>Handle glyph ink above cap height of font.<a href=#issue-f77cbeb9> ↵ </a></div><div class=issue>Is this the behavior we want? What if the float is on the same line as the initial letter?<a href=#issue-2ad0a0cb> ↵ </a></div></div>