css3-overflow/Overview.src.html

Thu, 16 Aug 2012 15:11:35 -0700

author
L. David Baron <dbaron@dbaron.org>
date
Thu, 16 Aug 2012 15:11:35 -0700
changeset 6493
bcbba88e4047
parent 6492
dcb554a16adc
child 6494
9634c4beb885
permissions
-rw-r--r--

Add issue on overflow in static media, as discussed at face-to-face meeting afternoon of 2012-08-13.

dbaron@6470 1 <!DOCTYPE html>
dbaron@6470 2 <html lang="en">
dbaron@6470 3 <head>
dbaron@6470 4 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
dbaron@6483 5 <title>CSS Overflow Module Level 3</title>
dbaron@6470 6 <link rel=contents href="#contents">
dbaron@6470 7 <link rel=index href="#index">
dbaron@6470 8 <link rel="stylesheet" type="text/css" href="../default.css">
dbaron@6470 9 <link rel="stylesheet" type="text/css"
dbaron@6470 10 href="http://www.w3.org/StyleSheets/TR/W3C-[STATUS].css">
dbaron@6475 11 <style>
dbaron@6477 12 table.source-demo-pair {
dbaron@6477 13 width: 100%;
dbaron@6477 14 }
dbaron@6481 15
dbaron@6475 16 .in-cards-demo {
dbaron@6475 17 width: 13em;
dbaron@6475 18 height: 8em;
dbaron@6475 19
dbaron@6475 20 padding: 4px;
dbaron@6475 21 border: medium solid blue;
dbaron@6475 22 margin: 6px;
dbaron@6475 23
dbaron@6475 24 font: medium/1.3 Times New Roman, Times, serif;
dbaron@6475 25 white-space: nowrap;
dbaron@6475 26 }
dbaron@6481 27
dbaron@6477 28 .bouncy-columns-demo {
dbaron@6477 29 width: 6em;
dbaron@6477 30 height: 10em;
dbaron@6477 31 float: left;
dbaron@6477 32 margin: 1em;
dbaron@6477 33 font: medium/1.25 Times New Roman, Times, serif;
dbaron@6477 34 white-space: nowrap;
dbaron@6477 35 }
dbaron@6477 36 .bouncy-columns-demo.one {
dbaron@6477 37 background: aqua; color: black;
dbaron@6477 38 transform: rotate(-3deg);
dbaron@6477 39 }
dbaron@6477 40 .bouncy-columns-demo.two {
dbaron@6477 41 background: yellow; color: black;
dbaron@6477 42 transform: rotate(3deg);
dbaron@6477 43 }
dbaron@6479 44
dbaron@6480 45 .article-font-inherit-demo {
dbaron@6480 46 font: 1em/1.25 Times New Roman, Times, serif;
dbaron@6480 47 white-space: nowrap;
dbaron@6480 48 }
dbaron@6480 49 .article-font-inherit-demo.one {
dbaron@6480 50 width: 12em;
dbaron@6480 51 font-size: 1.5em;
dbaron@6480 52 margin-bottom: 1em;
dbaron@6480 53 height: 4em;
dbaron@6480 54 }
dbaron@6480 55 .article-font-inherit-demo.two {
dbaron@6480 56 width: 11em;
dbaron@6480 57 margin-left: 5em;
dbaron@6480 58 margin-right: 2em;
dbaron@6480 59 }
dbaron@6480 60
dbaron@6481 61 .dark-columns-demo {
dbaron@6481 62 width: 6em;
dbaron@6481 63 height: 10em;
dbaron@6481 64 float: left;
dbaron@6481 65 margin-right: 1em;
dbaron@6481 66 font: medium/1.25 Times New Roman, Times, serif;
dbaron@6481 67 white-space: nowrap;
dbaron@6481 68 }
dbaron@6481 69 .dark-columns-demo.one {
dbaron@6481 70 background: aqua; color: black;
dbaron@6481 71 }
dbaron@6481 72 .dark-columns-demo.one :link {
dbaron@6481 73 color: blue;
dbaron@6481 74 }
dbaron@6481 75 .dark-columns-demo.one :visited {
dbaron@6481 76 color: purple;
dbaron@6481 77 }
dbaron@6481 78 .dark-columns-demo.two {
dbaron@6481 79 background: navy; color: white;
dbaron@6481 80 }
dbaron@6481 81 .dark-columns-demo.two :link {
dbaron@6481 82 color: aqua;
dbaron@6481 83 }
dbaron@6481 84 .dark-columns-demo.two :visited {
dbaron@6481 85 color: fuchsia;
dbaron@6481 86 }
dbaron@6481 87
dbaron@6479 88 .article-max-lines-demo {
dbaron@6479 89 font: 1em/1.25 Times New Roman, Times, serif;
dbaron@6479 90 white-space: nowrap;
dbaron@6479 91 }
dbaron@6479 92 .article-max-lines-demo.one::first-letter {
dbaron@6479 93 font-size: 2em;
dbaron@6479 94 line-height: 0.9;
dbaron@6479 95 }
dbaron@6479 96 .article-max-lines-demo.one {
dbaron@6479 97 font-size: 1.5em;
dbaron@6479 98 width: 16em;
dbaron@6479 99 }
dbaron@6479 100 .article-max-lines-demo.two {
dbaron@6479 101 width: 11.5em;
dbaron@6479 102 float: left; margin-right: 1em;
dbaron@6479 103 }
dbaron@6479 104 .article-max-lines-demo.three {
dbaron@6479 105 width: 11.5em;
dbaron@6479 106 float: left;
dbaron@6479 107 }
dbaron@6475 108 </style>
dbaron@6470 109 </head>
dbaron@6470 110
dbaron@6470 111 <div class="head">
dbaron@6470 112 <!--logo-->
dbaron@6470 113
dbaron@6483 114 <h1>CSS Overflow Module Level 3</h1>
dbaron@6470 115
dbaron@6470 116 <h2 class="no-num no-toc">[LONGSTATUS] [DATE]</h2>
dbaron@6470 117 <dl>
dbaron@6470 118 <dt>This version:
dbaron@6483 119 <dd><a href="[VERSION]">http://www.w3.org/TR/[YEAR]/ED-css3-overflow-[CDATE]/</a>
dbaron@6470 120
dbaron@6470 121 <dt>Latest version:
dbaron@6470 122 <dd><a href="http://www.w3.org/TR/[SHORTNAME]/">http://www.w3.org/TR/[SHORTNAME]/</a>
dbaron@6470 123
dbaron@6470 124 <dt>Editor's draft:
dbaron@6470 125 <dd><a href="http://dev.w3.org/csswg/[SHORTNAME]/">http://dev.w3.org/csswg/[SHORTNAME]/</a>
dbaron@6470 126
dbaron@6470 127 <!--
dbaron@6470 128 <dt>Previous version:
dbaron@6470 129 <dd><a href="http://www.w3.org/PreviousVersionURI">
dbaron@6470 130 http://www.w3.org/PreviousVersionURI</a>
dbaron@6470 131 -->
dbaron@6470 132
dbaron@6470 133 <dt>Issue Tracking:</dt>
dbaron@6470 134 <dd>Maintained in document (only editor's draft is current)
dbaron@6470 135
dbaron@6470 136 <dt>Feedback:</dt>
dbaron@6470 137 <dd><a href="http://lists.w3.org/Archives/Public/www-style/">www-style@w3.org</a> with subject line &ldquo;<kbd>[[SHORTNAME]] <var>&hellip; message topic &hellip;</var></kbd>&rdquo;
dbaron@6470 138
dbaron@6470 139 <dt>Editors:
dbaron@6470 140 <dd class="h-card vcard">
dbaron@6470 141 <a class="p-name fn u-url url" rel="author"
dbaron@6470 142 href="http://dbaron.org/">L. David Baron</a>,
dbaron@6470 143 <a class="p-org org" href="http://www.mozilla.org/">Mozilla</a>
dbaron@6470 144 </dl>
dbaron@6470 145
dbaron@6470 146 <!--copyright-->
dbaron@6470 147
dbaron@6470 148 <hr title="Separator for header">
dbaron@6470 149 </div>
dbaron@6470 150
dbaron@6470 151 <h2 class="no-num no-toc" id="abstract">Abstract</h2>
dbaron@6470 152
dbaron@6470 153 <p>
dbaron@6470 154 <a href="http://www.w3.org/TR/CSS/">CSS</a> is
dbaron@6470 155 a language for describing
dbaron@6470 156 the rendering of structured documents (such as HTML and XML)
dbaron@6470 157 on screen, on paper, in speech, etc.
dbaron@6470 158 This module contains the features of CSS
dbaron@6470 159 relating to new mechanisms of overflow handling in visual media (e.g., screen or paper).
dbaron@6470 160 In interactive media,
dbaron@6470 161 it describes features that allow the overflow
dbaron@6470 162 from a fixed size container
dbaron@6470 163 to be handled by pagination (displaying one page at a time).
dbaron@6470 164 It also describes features, applying to all visual media,
dbaron@6470 165 that allow the contents of an element
dbaron@6484 166 to be spread across multiple fragments,
dbaron@6484 167 allowing the contents to flow across multiple regions
dbaron@6484 168 or to have different styles for different fragments.
dbaron@6470 169 </p>
dbaron@6470 170
dbaron@6470 171 <h2 class="no-num no-toc" id="status">Status of this document</h2>
dbaron@6470 172
dbaron@6470 173 <!--status-->
dbaron@6470 174
dbaron@6470 175 <p>The following features are at risk: &hellip;
dbaron@6470 176
dbaron@6470 177 <h2 class="no-num no-toc" id="contents">
dbaron@6470 178 Table of contents</h2>
dbaron@6470 179
dbaron@6470 180 <!--toc-->
dbaron@6470 181
dbaron@6470 182 <h2 id="intro">
dbaron@6470 183 Introduction</h2>
dbaron@6470 184
dbaron@6470 185 <p>
dbaron@6470 186 In CSS Level 1 [[CSS1]], placing more content than would fit
dbaron@6470 187 inside an element with a specified size
dbaron@6470 188 was generally an authoring error.
dbaron@6470 189 Doing so caused the content to extend
dbaron@6470 190 outside the bounds of the element,
dbaron@6470 191 which would likely cause
dbaron@6470 192 that content to overlap with other elements.
dbaron@6470 193 </p>
dbaron@6470 194
dbaron@6470 195 <p>
dbaron@6470 196 CSS Level 2 [[CSS21]] introduced the 'overflow' property,
dbaron@6470 197 which allows authors to have overflow be handled by scrolling,
dbaron@6470 198 which means it is no longer an authoring error.
dbaron@6470 199 It also allows authors to specify
dbaron@6470 200 that overflow is handled by clipping,
dbaron@6470 201 which makes sense when the author's intent
dbaron@6470 202 is that the content not be shown.
dbaron@6470 203 </p>
dbaron@6470 204
dbaron@6470 205 <p>
dbaron@6470 206 However, scrolling is not the only way
dbaron@6470 207 to present large amounts of content,
dbaron@6470 208 and may even not be the optimal way.
dbaron@6470 209 After all, the codex replaced the scroll
dbaron@6470 210 as the common format for large written works
dbaron@6470 211 because of its advantages.
dbaron@6470 212 </p>
dbaron@6470 213
dbaron@6470 214 <p>
dbaron@6470 215 This specification introduces
dbaron@6470 216 a mechanism for Web pages to specify
dbaron@6484 217 that an element of a page should handle overflow
dbaron@6470 218 through pagination rather than through scrolling.
dbaron@6470 219 </p>
dbaron@6470 220
dbaron@6470 221 <p>
dbaron@6470 222 This specification also extends the concept of overflow
dbaron@6470 223 in another direction.
dbaron@6484 224 Instead of requiring that authors specify a single area
dbaron@6470 225 into which the content of an element must flow,
dbaron@6484 226 this specification allows authors to specify multiple fragments,
dbaron@6470 227 each with their own dimensions and styles,
dbaron@6470 228 so that the content of the element can flow from one to the next,
dbaron@6470 229 using as many as needed to place the content without overflowing.
dbaron@6470 230 </p>
dbaron@6470 231
dbaron@6470 232 <p>
dbaron@6470 233 In both of these cases, implementations must
dbaron@6470 234 break the content in the block-progression dimension.
dbaron@6470 235 Implementations must do this is described
dbaron@6470 236 in the CSS Fragmentation Module [[!CSS3-BREAK]].
dbaron@6470 237 </p>
dbaron@6470 238
dbaron@6483 239 <h2 id="scrolling-overflow">Scrolling and hidden overflow</h2>
dbaron@6483 240
dbaron@6483 241 <p class="issue">
dbaron@6483 242 Move material from [[CSS21]] and [[CSS3BOX]] here.
dbaron@6483 243 </p>
dbaron@6470 244
dbaron@6470 245 <h2 id="paginated-overflow">Paginated overflow</h2>
dbaron@6470 246
dbaron@6470 247 <p class="issue">overflow:paginate or overflow:pages (or paged-x, paged-y, paged-x-controls, paged-y-controls as css3-gcpm has?)</p>
dbaron@6470 248
dbaron@6470 249 <p class="issue">Ability to display N pages at once
dbaron@6470 250 rather than just one page at once?</p>
dbaron@6470 251
dbaron@6484 252 <h2 id="fragment-overflow">Fragment overflow</h2>
dbaron@6470 253
dbaron@6470 254 <p>
dbaron@6470 255 This section introduces and defines the meaning of
dbaron@6484 256 the new ''fragments'' value of the 'overflow' property.
dbaron@6470 257 </p>
dbaron@6470 258
dbaron@6470 259 <p>
dbaron@6484 260 When the computed value of 'overflow' for an element is ''fragments'',
dbaron@6470 261 and implementations would otherwise have created a box for the element,
dbaron@6491 262 then implementations must create a sequence of <dfn>fragment box</dfn>es
dbaron@6470 263 for that element.
dbaron@6491 264 (It is possible for an element with ''overflow: fragments''
dbaron@6491 265 to generate only one <i>fragment box</i>.
dbaron@6484 266 However, if an element's computed 'overflow' is not ''fragments'',
dbaron@6484 267 then its box is not a <i>fragment box</i>.)
dbaron@6484 268 Every <i>fragment box</i> is a fragmentation container,
dbaron@6491 269 and any overflow
dbaron@6491 270 that would cause that fragmentation container to fragment
dbaron@6491 271 causes another <i>fragment box</i> created as a next sibling
dbaron@6470 272 of the previous one.
dbaron@6470 273 <span class="issue">Or is it as though it's a next sibling of
dbaron@6470 274 the element? Need to figure out exactly how this interacts with
dbaron@6470 275 other box-level fixup.</span>
dbaron@6492 276 Additionally, if the <i>fragment box</i> is also
dbaron@6492 277 a multi-column box (as defined in [[!CSS3COL]]
dbaron@6492 278 <span class="issue">though it defines <i>multi-column element</i></span>)
dbaron@6492 279 any content that would lead to the creation of <i>overflow columns</i> [[!CSS3COL]]
dbaron@6492 280 instead is flown into an additional fragment box.
dbaron@6491 281 However, fragment boxes may themselves be broken
dbaron@6491 282 (due to fragmentation in a fragmentation context outside of them,
dbaron@6491 283 such as pages, columns, or other fragment boxes);
dbaron@6491 284 such breaking leads to fragments of the same fragment box
dbaron@6491 285 rather than multiple fragment boxes.
dbaron@6491 286 (This matters because fragment boxes may be styled by their index;
dbaron@6491 287 such breaking leads to multiple fragments of a fragment box
dbaron@6491 288 with a single index.
dbaron@6491 289 This design choice is so that
dbaron@6491 290 breaking a fragment box across pages does not break
dbaron@6491 291 the association of indices to particular pieces of content.)
dbaron@6491 292 <span class="issue">Should a forced break that breaks to
dbaron@6491 293 an outer fragmentation context cause a new fragment of a single
dbaron@6491 294 fragment box or a new fragment box?</span>
dbaron@6491 295 <span class="issue">Should we find a term other than
dbaron@6491 296 <i>fragment box</i> here to make this a little less confusing?</span>
dbaron@6470 297 </p>
dbaron@6470 298
dbaron@6470 299 <p class="issue">
dbaron@6491 300 What if we want to be able to style the pieces of an element
dbaron@6491 301 split within another type of fragmentation context?
dbaron@6491 302 These rules prevent ever using ''::nth-fragment()'' for that,
dbaron@6491 303 despite that the name seems the most logical name for such a feature.
dbaron@6470 304 </p>
dbaron@6470 305
dbaron@6475 306 <div class="example">
dbaron@6477 307 <table class="source-demo-pair"><tr><td><pre>&lt;!DOCTYPE HTML&gt;
dbaron@6475 308 &lt;title&gt;Breaking content into
dbaron@6475 309 equal-sized cards&lt;/title&gt;
dbaron@6475 310 &lt;style&gt;
dbaron@6475 311 .in-cards {
dbaron@6484 312 overflow: fragments;
dbaron@6475 313
dbaron@6475 314 width: 13em;
dbaron@6475 315 height: 8em;
dbaron@6475 316
dbaron@6475 317 padding: 4px;
dbaron@6475 318 border: medium solid blue;
dbaron@6475 319 margin: 6px;
dbaron@6475 320
dbaron@6475 321 font: medium/1.3 Times New
dbaron@6475 322 Roman, Times, serif;
dbaron@6475 323 }
dbaron@6475 324 &lt;/style&gt;
dbaron@6475 325 &lt;div class="in-cards"&gt;
dbaron@6475 326 In this example, the text in the div
dbaron@6475 327 is broken into a series of cards.
dbaron@6475 328 These cards all have the same style.
dbaron@6475 329 The presence of enough content to
dbaron@6475 330 overflow one of the cards causes
dbaron@6475 331 another one to be created. The second
dbaron@6475 332 card is created just like it's the
dbaron@6475 333 next sibling of the first.
dbaron@6477 334 &lt;/div&gt;</pre></td><td>
dbaron@6475 335 <div class="in-cards-demo">In this example, the text in the<br>div is broken into a series of<br>cards. These cards all have the<br>same style. The presence of<br>enough content to overflow<br>one of the cards causes another</div>
dbaron@6475 336 <div class="in-cards-demo">one to be created. The second<br>card is created just like it's the<br>next sibling of the first.</div>
dbaron@6475 337 </td></tr></table>
dbaron@6475 338 </div>
dbaron@6475 339
dbaron@6487 340 <p class="issue">
dbaron@6487 341 We should specify that ''overflow: fragments'' does not apply
dbaron@6487 342 to at least some table parts,
dbaron@6487 343 and perhaps other elements as well.
dbaron@6487 344 We need to determine exactly which ones.
dbaron@6487 345 </p>
dbaron@6487 346
dbaron@6488 347 <p class="issue">
dbaron@6488 348 This specification needs to say which type of
dbaron@6488 349 fragmentation context is created
dbaron@6488 350 so that it's clear which values of the 'break' property
dbaron@6488 351 cause breaks within this context.
dbaron@6488 352 We probably want ''break: regions'' to apply.
dbaron@6488 353 </p>
dbaron@6488 354
dbaron@6484 355 <h3 id="fragment-styling">Fragment styling</h3>
dbaron@6470 356
dbaron@6484 357 <h4 id="fragment-pseudo-element">The ::nth-fragment() pseudo-element</h4>
dbaron@6470 358
dbaron@6470 359 <p>
dbaron@6484 360 The ::nth-fragment() pseudo-element is a pseudo-element
dbaron@6484 361 that describes some of the <i>fragment box</i>es generated by an element.
dbaron@6470 362 The argument to the pseudo-element takes the same syntax
dbaron@6470 363 as the argument to the :nth-child() pseudo-class
dbaron@6470 364 defined in [[!SELECT]], and has the same meaning
dbaron@6470 365 except that the number is relative to
dbaron@6484 366 <i>fragment box</i>es generated by the element
dbaron@6470 367 instead of siblings of the element.
dbaron@6470 368 </p>
dbaron@6470 369
dbaron@6470 370 <p class="note">
dbaron@6484 371 Selectors that allow addressing fragments
dbaron@6470 372 by counting from the end rather than the start
dbaron@6470 373 are intentionally not provided.
dbaron@6470 374 Such selectors would interfere with determining
dbaron@6484 375 the number of fragments.
dbaron@6470 376 </p>
dbaron@6470 377
dbaron@6489 378 <p class="issue">
dbaron@6489 379 Depending on future discussions,
dbaron@6489 380 this ''::nth-fragment(<var>an+b</var>)'' syntax
dbaron@6489 381 may be replaced with
dbaron@6489 382 the new ''::fragment:nth(<var>an+b</var>)'' syntax.
dbaron@6489 383 </p>
dbaron@6489 384
dbaron@6484 385 <h4 id="style-of-fragments">Styling of fragments</h4>
dbaron@6470 386
dbaron@6470 387 <p class="issue">
dbaron@6484 388 Should this apply to fragment overflow only,
dbaron@6470 389 or also to paginated overflow?
dbaron@6470 390 (If it applies,
dbaron@6470 391 then stricter property restrictions would be needed
dbaron@6470 392 for paginated overflow.)
dbaron@6470 393 </p>
dbaron@6470 394
dbaron@6470 395 <p>
dbaron@6484 396 In the absence of rules with ''::nth-fragment()'' pseudo-elements,
dbaron@6484 397 the computed style for each <i>fragment box</i>
dbaron@6470 398 is the computed style for the element
dbaron@6484 399 for which the <i>fragment box</i> was created.
dbaron@6484 400 However, the style for a <i>fragment box</i> is also influenced
dbaron@6470 401 by rules whose selector's <i>subject</i> [[!SELECT]]
dbaron@6484 402 has an ''::nth-fragment()'' pseudo-element,
dbaron@6484 403 if the 1-based number of the <i>fragment box</i> matches
dbaron@6484 404 that ''::nth-fragment()'' pseudo-element
dbaron@6484 405 and the selector (excluding the ''::nth-fragment()'' pseudo-element)
dbaron@6484 406 matches the element generating the fragments.
dbaron@6470 407 </p>
dbaron@6470 408
dbaron@6486 409 <p>
dbaron@6486 410 When determining the style of the <i>fragment box</i>,
dbaron@6486 411 these rules that match the fragment pseudo-element
dbaron@6486 412 cascade together with the rules that match the element,
dbaron@6486 413 with the fragment pseudo-element adding the specificity
dbaron@6486 414 of a pseudo-class to the specificity calculation.
dbaron@6486 415 <span class="issue">Does this need to be specified in
dbaron@6486 416 the cascading module as well?</span>
dbaron@6486 417 </p>
dbaron@6486 418
dbaron@6477 419 <div class="example">
dbaron@6477 420 <table class="source-demo-pair"><tr><td><pre>&lt;!DOCTYPE HTML&gt;
dbaron@6477 421 &lt;style&gt;
dbaron@6477 422 .bouncy-columns {
dbaron@6484 423 overflow: fragments;
dbaron@6477 424 width: 6em;
dbaron@6477 425 height: 10em;
dbaron@6477 426 float: left;
dbaron@6477 427 margin: 1em;
dbaron@6477 428 font: medium/1.25 Times New
dbaron@6477 429 Roman, Times, serif;
dbaron@6477 430 }
dbaron@6484 431 .bouncy-columns::nth-fragment(1) {
dbaron@6477 432 background: aqua; color: black;
dbaron@6477 433 transform: rotate(-3deg);
dbaron@6477 434 }
dbaron@6484 435 .bouncy-columns::nth-fragment(2) {
dbaron@6477 436 background: yellow; color: black;
dbaron@6477 437 transform: rotate(3deg);
dbaron@6477 438 }
dbaron@6477 439 &lt;/style&gt;
dbaron@6477 440 &lt;div class="bouncy-columns"&gt;
dbaron@6477 441 <i>...</i>
dbaron@6477 442 &lt;/div&gt;</pre></td><td>
dbaron@6477 443 <div class="bouncy-columns-demo one">In this<br>example, the<br>text in the div<br>is broken into<br>a series of<br>columns. The<br>author<br>probably</div>
dbaron@6477 444 <div class="bouncy-columns-demo two">intended the<br>text to fill two<br>columns. But<br>if it happens to<br>fill three<br>columns, the<br>third column is<br>still created. It</div>
dbaron@6484 445 <div class="bouncy-columns-demo">just doesn't<br>have any<br>fragment-specific<br>styling because<br>the author<br>didn't give it<br>any.</div>
dbaron@6477 446 </td></tr></table>
dbaron@6477 447 </div>
dbaron@6477 448
dbaron@6470 449 <p>
dbaron@6484 450 Styling an ''::nth-fragment()'' pseudo-element with the 'overflow'
dbaron@6490 451 property does take effect;
dbaron@6490 452 if a <i>fragment box</i> has a
dbaron@6490 453 computed value of 'overflow' other than ''fragments''
dbaron@6490 454 then that fragment box is the last fragment.
dbaron@6490 455 However, overriding ''overflow'' on the first fragment
dbaron@6490 456 does not cause the <i>fragment box</i> not to exist;
dbaron@6490 457 whether there are fragment boxes at all is determined by
dbaron@6490 458 the computed value of overflow for the element.
dbaron@6470 459 </p>
dbaron@6470 460
dbaron@6470 461 <p>
dbaron@6485 462 Styling an ''::nth-fragment()'' pseudo-element with the 'content'
dbaron@6485 463 property has no effect;
dbaron@6485 464 the computed value of 'content' for the fragment box
dbaron@6485 465 remains the same as the computed value of content for the element.
dbaron@6485 466 </p>
dbaron@6485 467
dbaron@6485 468 <p>
dbaron@6484 469 Specifying ''display: none'' for a <i>fragment box</i> causes
dbaron@6484 470 the fragment box with that index not to be generated.
dbaron@6470 471 However, in terms of the indices
dbaron@6484 472 used for matching ''::nth-fragment()'' pseudo-elements
dbaron@6484 473 of later fragment boxes,
dbaron@6470 474 it still counts as though it was generated.
dbaron@6470 475 However, since it is not generated, it does not contain any content.
dbaron@6470 476 </p>
dbaron@6470 477
dbaron@6470 478 <p class="issue">
dbaron@6470 479 Would it make more sense to forbid ''display:none''?
dbaron@6470 480 Or perhaps to forbid 'display', 'position', 'float',
dbaron@6470 481 and similar (in addition to 'overflow')?
dbaron@6470 482 </p>
dbaron@6470 483
dbaron@6470 484 <p>
dbaron@6470 485 To match the model for other pseudo-elements
dbaron@6470 486 where the pseudo-elements live inside their corresponding element,
dbaron@6484 487 declarations in ''::nth-fragment()'' pseudo-elements override
dbaron@6470 488 declarations in rules without the pseudo-element.
dbaron@6470 489 The relative priority within such declarations is determined
dbaron@6470 490 by normal cascading order (see [[!CSS21]]).
dbaron@6470 491 </p>
dbaron@6470 492
dbaron@6470 493 <p>
dbaron@6484 494 Styles specified on ''::nth-fragment()'' pseudo-elements
dbaron@6484 495 do affect inheritance to content within the <i>fragment box</i>.
dbaron@6484 496 In other words, the content within the <i>fragment box</i> must
dbaron@6484 497 inherit from the fragment box's style (i.e., the pseudo-element style)
dbaron@6470 498 rather than directly from the element.
dbaron@6484 499 This means that elements split between fragment boxes may
dbaron@6470 500 have different styles for different parts of the element.
dbaron@6470 501 </p>
dbaron@6470 502
dbaron@6472 503 <p class="issue">
dbaron@6472 504 This inheritance rule allows specifying styles indirectly
dbaron@6472 505 (by using explicit ''inherit'' or using default inheritance
dbaron@6472 506 on properties that don't apply to '':first-letter'')
dbaron@6472 507 that can't be specified directly
dbaron@6472 508 (based on the rules in the next section).
dbaron@6472 509 This is a problem.
dbaron@6484 510 The restrictions that apply to styling inside fragments
dbaron@6484 511 should also apply to inheritance from fragments.
dbaron@6472 512 </p>
dbaron@6472 513
dbaron@6480 514 <div class="example">
dbaron@6480 515 <table class="source-demo-pair"><tr><td><pre>&lt;!DOCTYPE HTML&gt;
dbaron@6480 516 &lt;style&gt;
dbaron@6480 517 .article {
dbaron@6484 518 overflow: fragments;
dbaron@6480 519 }
dbaron@6484 520 .article::nth-fragment(1) {
dbaron@6480 521 font-size: 1.5em;
dbaron@6480 522 margin-bottom: 1em;
dbaron@6480 523 height: 4em;
dbaron@6480 524 }
dbaron@6491 525 .article::nth-fragment(2) {
dbaron@6480 526 margin-left: 5em;
dbaron@6480 527 margin-right: 2em;
dbaron@6480 528 }
dbaron@6480 529 &lt;/style&gt;
dbaron@6480 530 &lt;div class="article"&gt;
dbaron@6480 531 The &lt;code&gt;font-size&lt;/code&gt; property<i>...</i>
dbaron@6480 532 &lt;/div&gt;</pre></td><td>
dbaron@6484 533 <div class="article-font-inherit-demo one">The <code>font-size</code> property<br>specified on the fragment<br>is inherited into the</div>
dbaron@6484 534 <div class="article-font-inherit-demo two">descendants of the fragment.<br>This means that inherited<br>properties can be used<br>reliably on a fragment, as in<br>this example.</div>
dbaron@6480 535 </td></tr></table>
dbaron@6480 536 </div>
dbaron@6478 537
dbaron@6484 538 <h4 id="style-in-fragments">Styling inside fragments</h4>
dbaron@6470 539
dbaron@6470 540 <p class="issue">
dbaron@6484 541 Should this apply to fragment overflow only,
dbaron@6470 542 or also to paginated overflow,
dbaron@6470 543 or even to pagination across pages?
dbaron@6470 544 </p>
dbaron@6470 545
dbaron@6470 546 <p>
dbaron@6484 547 The ''::nth-fragment()'' pseudo-element
dbaron@6470 548 can also be used to style
dbaron@6484 549 content inside of a <i>fragment box</i>.
dbaron@6470 550 Unlike the ''::first-line'' and ''::first-letter'' pseudo-elements,
dbaron@6484 551 the ''::nth-fragment()'' pseudo-element can be applied
dbaron@6470 552 to parts of the selector other than the subject:
dbaron@6470 553 in particular, it can match ancestors of the subject.
dbaron@6470 554 However, the only CSS properties applied
dbaron@6470 555 by rules with such selectors
dbaron@6470 556 are those that apply
dbaron@6470 557 to the ''::first-letter'' pseudo-element.
dbaron@6470 558 </p>
dbaron@6470 559
dbaron@6470 560 <p>
dbaron@6470 561 To be more precise,
dbaron@6484 562 when a rule's selector has ''::nth-fragment()'' pseudo-elements
dbaron@6470 563 attached to parts of the selector other than the subject,
dbaron@6470 564 the declarations in that rule apply to
dbaron@6470 565 a fragment (or pseudo-element thereof) when:
dbaron@6470 566 </p>
dbaron@6470 567 <ol>
dbaron@6470 568 <li>
dbaron@6470 569 the declarations are for properties that apply to the
dbaron@6470 570 ''::first-letter'' pseudo-element,
dbaron@6470 571 </li>
dbaron@6470 572 <li>
dbaron@6470 573 the declarations would apply to
dbaron@6470 574 that fragment (or pseudo-element thereof)
dbaron@6484 575 had those ''::nth-fragment()'' pseudo-elements been removed,
dbaron@6470 576 with a particular association between
dbaron@6470 577 each sequence of simple selectors and the element it matched,
dbaron@6470 578 and
dbaron@6470 579 </li>
dbaron@6470 580 <li>
dbaron@6484 581 for each removed ''::nth-fragment()'' pseudo-element,
dbaron@6484 582 the fragment lives within a <i>fragment box</i>
dbaron@6470 583 of the element associated in that association
dbaron@6470 584 with the selector that the pseudo-element was attached to,
dbaron@6470 585 and whose index matches the pseudo-element.
dbaron@6470 586 </li>
dbaron@6470 587 </ol>
dbaron@6470 588
dbaron@6481 589 <div class="example">
dbaron@6481 590 <table class="source-demo-pair"><tr><td><pre>&lt;!DOCTYPE HTML&gt;
dbaron@6481 591 &lt;style&gt;
dbaron@6481 592 .dark-columns {
dbaron@6484 593 overflow: fragments;
dbaron@6481 594 width: 6em;
dbaron@6481 595 height: 10em;
dbaron@6481 596 float: left;
dbaron@6481 597 margin-right: 1em;
dbaron@6481 598 font: medium/1.25 Times New
dbaron@6481 599 Roman, Times, serif;
dbaron@6481 600 }
dbaron@6484 601 .dark-columns::nth-fragment(1) {
dbaron@6481 602 background: aqua; color: black;
dbaron@6481 603 }
dbaron@6484 604 .dark-columns::nth-fragment(1) :link {
dbaron@6481 605 color: blue;
dbaron@6481 606 }
dbaron@6484 607 .dark-columns::nth-fragment(1) :visited {
dbaron@6481 608 color: purple;
dbaron@6481 609 }
dbaron@6484 610 .dark-columns::nth-fragment(2) {
dbaron@6481 611 background: navy; color: white;
dbaron@6481 612 }
dbaron@6484 613 .dark-columns::nth-fragment(2) :link {
dbaron@6481 614 color: aqua;
dbaron@6481 615 }
dbaron@6484 616 .dark-columns::nth-fragment(2) :visited {
dbaron@6481 617 color: fuchsia;
dbaron@6481 618 }
dbaron@6481 619 &lt;/style&gt;
dbaron@6481 620 &lt;div class="dark-columns"&gt;
dbaron@6481 621 <i>...</i>
dbaron@6481 622 &lt;/div&gt;</pre></td><td>
dbaron@6484 623 <div class="dark-columns-demo one">In this<br><a href="http://en.wiktionary.org/wiki/example">example</a>, the<br>text flows<br>from one<br>light-colored<br>fragment into<br>another<br>dark-colored</div>
dbaron@6484 624 <div class="dark-columns-demo two">fragment. We<br>therefore want<br>different styles<br>for <a href="http://www.w3.org/Provider/Style/IntoContext.html">hyperlinks</a><br>in the different<br>fragments.</div>
dbaron@6481 625 </td></tr></table>
dbaron@6481 626 </div>
dbaron@6481 627
dbaron@6478 628
dbaron@6470 629 <h3 id="max-lines">The 'max-lines' property</h3>
dbaron@6470 630
dbaron@6470 631 <p>
dbaron@6470 632 Authors may wish to style the opening lines of an element
dbaron@6470 633 with different styles
dbaron@6484 634 by putting those opening lines in a separate fragment.
dbaron@6470 635 However, since it may be difficult to predict the exact height
dbaron@6470 636 occupied by those lines
dbaron@6484 637 in order to restrict the first fragment to that height,
dbaron@6470 638 this specification introduces a 'max-lines' property
dbaron@6484 639 that forces a fragment to break
dbaron@6470 640 after a specified number of lines.
dbaron@6470 641 This forces a break after the given number of lines
dbaron@6470 642 contained within the element or its descendants,
dbaron@6470 643 as long as those lines are in the same block formatting context.
dbaron@6470 644 </p>
dbaron@6470 645
dbaron@6470 646 <table class=propdef>
dbaron@6470 647 <tr>
dbaron@6470 648 <th>Name:
dbaron@6470 649 <td><dfn>max-lines</dfn>
dbaron@6470 650 <tr>
dbaron@6470 651 <th><a href="#values">Value</a>:
dbaron@6470 652 <td>none | &lt;integer&gt;
dbaron@6470 653 <tr>
dbaron@6470 654 <th>Initial:
dbaron@6470 655 <td>none
dbaron@6470 656 <tr>
dbaron@6470 657 <th>Applies to:
dbaron@6484 658 <td>fragment boxes
dbaron@6470 659 <tr>
dbaron@6470 660 <th>Inherited:
dbaron@6470 661 <td>no
dbaron@6470 662 <tr>
dbaron@6482 663 <th>Animatable:
dbaron@6482 664 <td>as <a href="http://www.w3.org/TR/css3-transitions/#animatable-types">integer</a>
dbaron@6482 665 <tr>
dbaron@6470 666 <th>Percentages:
dbaron@6470 667 <td>N/A
dbaron@6470 668 <tr>
dbaron@6470 669 <th>Media:
dbaron@6470 670 <td>visual
dbaron@6470 671 <tr>
dbaron@6470 672 <th>Computed&nbsp;value:
dbaron@6470 673 <td>specified value
dbaron@6470 674 <tr>
dbaron@6470 675 <th>Canonical order:
dbaron@6470 676 <td><abbr title="follows order of property value definition">per grammar</abbr>
dbaron@6470 677 </table>
dbaron@6470 678
dbaron@6470 679 <dl>
dbaron@6470 680 <dt>none
dbaron@6470 681 <dd>
dbaron@6470 682 <p>
dbaron@6470 683 Breaks occur only as specified elsewhere.
dbaron@6470 684 </p>
dbaron@6470 685 </dd>
dbaron@6470 686
dbaron@6470 687 <dt>&lt;integer&gt;
dbaron@6470 688 <dd>
dbaron@6470 689 <p>
dbaron@6470 690 In addition to any breaks specified elsewhere,
dbaron@6470 691 a break is forced before any line that would exceed
dbaron@6470 692 the given number of lines
dbaron@6470 693 being placed inside the element
dbaron@6470 694 (excluding lines that are in
dbaron@6470 695 a different block formatting context from
dbaron@6470 696 the block formatting context to which
dbaron@6470 697 an unstyled child of the element would belong).
dbaron@6470 698 </p>
dbaron@6470 699
dbaron@6470 700 <p class="issue">
dbaron@6470 701 If there are multiple boundaries between this line
dbaron@6470 702 and the previous, where exactly (in terms of element
dbaron@6470 703 boundaries) is the break forced?
dbaron@6470 704 </p>
dbaron@6470 705
dbaron@6470 706 <p>
dbaron@6470 707 Only positive integers are accepted.
dbaron@6470 708 Zero or negative integers are a parse error.
dbaron@6470 709 </p>
dbaron@6470 710 </dd>
dbaron@6470 711 </dl>
dbaron@6470 712
dbaron@6484 713 <p class="issue">Should this apply to fragment overflow only, or also
dbaron@6470 714 to pagination?</p>
dbaron@6470 715
dbaron@6479 716 <div class="example">
dbaron@6479 717 <table class="source-demo-pair"><tr><td><pre>&lt;!DOCTYPE HTML&gt;
dbaron@6479 718 &lt;style&gt;
dbaron@6479 719 .article {
dbaron@6484 720 overflow: fragments;
dbaron@6479 721 }
dbaron@6479 722 .article::first-letter {
dbaron@6479 723 font-size: 2em;
dbaron@6479 724 line-height: 0.9;
dbaron@6479 725 }
dbaron@6484 726 .article::nth-fragment(1) {
dbaron@6479 727 font-size: 1.5em;
dbaron@6479 728 max-lines: 3;
dbaron@6479 729 }
dbaron@6491 730 .article::nth-fragment(2) {
dbaron@6479 731 column-count: 2;
dbaron@6479 732 }
dbaron@6479 733 &lt;/style&gt;
dbaron@6479 734 &lt;div class="article"&gt;
dbaron@6479 735 <i>...</i>
dbaron@6479 736 &lt;/div&gt;</pre></td><td>
dbaron@6479 737 <div class="article-max-lines-demo one">The max-lines property allows<br>authors to use a larger font for the first<br>few lines of an article. Without the</div>
dbaron@6479 738 <div class="article-max-lines-demo two">max-lines property, authors<br>might have to use the<br>'height' property instead, but<br>that would leave a slight gap<br>if the author miscalculated<br>how much height a given<br>number of lines would<br>occupy (which might be</div>
dbaron@6479 739 <div class="article-max-lines-demo three">particularly hard if the author<br>didn't know what text would<br>be filling the space, exactly<br>what font would be used, or<br>exactly which platform's font<br>rendering would be used to<br>display the font).</div>
dbaron@6479 740 </td></tr></table>
dbaron@6479 741 </div>
dbaron@6478 742
dbaron@6493 743 <h2 id="static-media">Overflow in static media</h2>
dbaron@6493 744
dbaron@6493 745 <p class="issue">
dbaron@6493 746 This specification should define useful behavior
dbaron@6493 747 for all values of 'overflow'
dbaron@6493 748 in static media (such as print).
dbaron@6493 749 Current implementation behavior is quite poor and
dbaron@6493 750 produces unexpected results when authors have not considered
dbaron@6493 751 what will happen when
dbaron@6493 752 the content they produce for interactive media
dbaron@6493 753 is printed.
dbaron@6493 754 </p>
dbaron@6493 755
dbaron@6470 756 <h2 id="conformance">
dbaron@6470 757 Conformance</h2>
dbaron@6470 758
dbaron@6470 759 <h3 id="placement">
dbaron@6470 760 Module interactions</h3>
dbaron@6470 761
dbaron@6470 762 <p>This module extends the 'overflow'
dbaron@6470 763 feature defined in [[CSS21]] section 11.1.1. It defines additional
dbaron@6470 764 overflow handling mechanisms that implementations must implement as
dbaron@6470 765 described in this module in order to conform to this module.</p>
dbaron@6470 766
dbaron@6470 767 <p>No properties in this module apply to the <code>::first-line</code> or
dbaron@6470 768 <code>::first-letter</code> pseudo-elements.</p>
dbaron@6470 769
dbaron@6470 770 <h3 id="values">
dbaron@6470 771 Values</h3>
dbaron@6470 772
dbaron@6470 773 <p>This specification follows the
dbaron@6470 774 <a href="http://www.w3.org/TR/CSS21/about.html#property-defs">CSS property
dbaron@6470 775 definition conventions</a> from [[!CSS21]]. Value types not defined in
dbaron@6470 776 this specification are defined in CSS Level 2 Revision 1 [[!CSS21]].
dbaron@6470 777 Other CSS modules may expand the definitions of these value types: for
dbaron@6470 778 example [[CSS3COLOR]], when combined with this module, expands the
dbaron@6470 779 definition of the &lt;color&gt; value type as used in this specification.</p>
dbaron@6470 780
dbaron@6470 781 <p>In addition to the property-specific values listed in their definitions,
dbaron@6470 782 all properties defined in this specification also accept the
dbaron@6470 783 <a href="http://www.w3.org/TR/CSS21/cascade.html#value-def-inherit">inherit</a>
dbaron@6470 784 keyword as their property value. For readability it has not been repeated
dbaron@6470 785 explicitly.
dbaron@6470 786
dbaron@6470 787
dbaron@6470 788 <h3 id="conventions">
dbaron@6470 789 Document conventions</h3>
dbaron@6470 790
dbaron@6470 791 <p>Conformance requirements are expressed with a combination of
dbaron@6470 792 descriptive assertions and RFC 2119 terminology. The key words “MUST”,
dbaron@6470 793 “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”,
dbaron@6470 794 “RECOMMENDED”, “MAY”, and “OPTIONAL” in the normative parts of this
dbaron@6470 795 document are to be interpreted as described in RFC 2119.
dbaron@6470 796 However, for readability, these words do not appear in all uppercase
dbaron@6470 797 letters in this specification.
dbaron@6470 798
dbaron@6470 799 <p>All of the text of this specification is normative except sections
dbaron@6470 800 explicitly marked as non-normative, examples, and notes. [[!RFC2119]]</p>
dbaron@6470 801
dbaron@6470 802 <p>Examples in this specification are introduced with the words “for example”
dbaron@6470 803 or are set apart from the normative text with <code>class="example"</code>,
dbaron@6470 804 like this:
dbaron@6470 805
dbaron@6470 806 <div class="example">
dbaron@6470 807 <p>This is an example of an informative example.</p>
dbaron@6470 808 </div>
dbaron@6470 809
dbaron@6470 810 <p>Informative notes begin with the word “Note” and are set apart from the
dbaron@6470 811 normative text with <code>class="note"</code>, like this:
dbaron@6470 812
dbaron@6470 813 <p class="note">Note, this is an informative note.</p>
dbaron@6470 814
dbaron@6470 815 <h3 id="conformance-classes">
dbaron@6470 816 Conformance classes</h3>
dbaron@6470 817
dbaron@6483 818 <p>Conformance to CSS Overflow Module Level 3
dbaron@6470 819 is defined for three conformance classes:
dbaron@6470 820 <dl>
dbaron@6470 821 <dt><dfn title="style sheet!!as conformance class">style sheet</dfn>
dbaron@6470 822 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS
dbaron@6470 823 style sheet</a>.
dbaron@6470 824 <dt><dfn>renderer</dfn></dt>
dbaron@6470 825 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
dbaron@6470 826 that interprets the semantics of a style sheet and renders
dbaron@6470 827 documents that use them.
dbaron@6470 828 <dt><dfn id="authoring-tool">authoring tool</dfn></dt>
dbaron@6470 829 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
dbaron@6470 830 that writes a style sheet.
dbaron@6470 831 </dl>
dbaron@6470 832
dbaron@6483 833 <p>A style sheet is conformant to CSS Overflow Module Level 3
dbaron@6470 834 if all of its statements that use syntax defined in this module are valid
dbaron@6470 835 according to the generic CSS grammar and the individual grammars of each
dbaron@6470 836 feature defined in this module.
dbaron@6470 837
dbaron@6483 838 <p>A renderer is conformant to CSS Overflow Module Level 3
dbaron@6470 839 if, in addition to interpreting the style sheet as defined by the
dbaron@6470 840 appropriate specifications, it supports all the features defined
dbaron@6483 841 by CSS Overflow Module Level 3 by parsing them correctly
dbaron@6470 842 and rendering the document accordingly. However, the inability of a
dbaron@6470 843 UA to correctly render a document due to limitations of the device
dbaron@6470 844 does not make the UA non-conformant. (For example, a UA is not
dbaron@6470 845 required to render color on a monochrome monitor.)
dbaron@6470 846
dbaron@6483 847 <p>An authoring tool is conformant to CSS Overflow Module Level 3
dbaron@6470 848 if it writes style sheets that are syntactically correct according to the
dbaron@6470 849 generic CSS grammar and the individual grammars of each feature in
dbaron@6470 850 this module, and meet all other conformance requirements of style sheets
dbaron@6470 851 as described in this module.
dbaron@6470 852
dbaron@6470 853 <h3 id="partial">
dbaron@6470 854 Partial implementations</h3>
dbaron@6470 855
dbaron@6470 856 <p>So that authors can exploit the forward-compatible parsing rules to
dbaron@6470 857 assign fallback values, CSS renderers <strong>must</strong>
dbaron@6470 858 treat as invalid (and <a href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignore
dbaron@6470 859 as appropriate</a>) any at-rules, properties, property values, keywords,
dbaron@6470 860 and other syntactic constructs for which they have no usable level of
dbaron@6470 861 support. In particular, user agents <strong>must not</strong> selectively
dbaron@6470 862 ignore unsupported component values and honor supported values in a single
dbaron@6470 863 multi-value property declaration: if any value is considered invalid
dbaron@6470 864 (as unsupported values must be), CSS requires that the entire declaration
dbaron@6470 865 be ignored.</p>
dbaron@6470 866
dbaron@6470 867 <h3 id="experimental">
dbaron@6470 868 Experimental implementations</h3>
dbaron@6470 869
dbaron@6470 870 <p>To avoid clashes with future CSS features, the CSS2.1 specification
dbaron@6470 871 reserves a <a href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed
dbaron@6470 872 syntax</a> for proprietary and experimental extensions to CSS.
dbaron@6470 873
dbaron@6470 874 <p>Prior to a specification reaching the Candidate Recommendation stage
dbaron@6470 875 in the W3C process, all implementations of a CSS feature are considered
dbaron@6470 876 experimental. The CSS Working Group recommends that implementations
dbaron@6470 877 use a vendor-prefixed syntax for such features, including those in
dbaron@6470 878 W3C Working Drafts. This avoids incompatibilities with future changes
dbaron@6470 879 in the draft.
dbaron@6470 880 </p>
dbaron@6470 881
dbaron@6470 882 <h3 id="testing">
dbaron@6470 883 Non-experimental implementations</h3>
dbaron@6470 884
dbaron@6470 885 <p>Once a specification reaches the Candidate Recommendation stage,
dbaron@6470 886 non-experimental implementations are possible, and implementors should
dbaron@6470 887 release an unprefixed implementation of any CR-level feature they
dbaron@6470 888 can demonstrate to be correctly implemented according to spec.
dbaron@6470 889
dbaron@6470 890 <p>To establish and maintain the interoperability of CSS across
dbaron@6470 891 implementations, the CSS Working Group requests that non-experimental
dbaron@6470 892 CSS renderers submit an implementation report (and, if necessary, the
dbaron@6470 893 testcases used for that implementation report) to the W3C before
dbaron@6470 894 releasing an unprefixed implementation of any CSS features. Testcases
dbaron@6470 895 submitted to W3C are subject to review and correction by the CSS
dbaron@6470 896 Working Group.
dbaron@6470 897
dbaron@6470 898 <p>Further information on submitting testcases and implementation reports
dbaron@6470 899 can be found from on the CSS Working Group's website at
dbaron@6470 900 <a href="http://www.w3.org/Style/CSS/Test/">http://www.w3.org/Style/CSS/Test/</a>.
dbaron@6470 901 Questions should be directed to the
dbaron@6470 902 <a href="http://lists.w3.org/Archives/Public/public-css-testsuite">public-css-testsuite@w3.org</a>
dbaron@6470 903 mailing list.
dbaron@6470 904
dbaron@6470 905 <h3 id="cr-exit-criteria">
dbaron@6470 906 CR exit criteria</h3>
dbaron@6470 907
dbaron@6470 908 <p class=issue>[Change or remove the following CR exit criteria if
dbaron@6470 909 the spec is not a module, but, e.g., a Note or a profile. This text was <a
dbaron@6470 910 href="http://www.w3.org/Style/CSS/Tracker/actions/44"> decided on 2008-06-04.</a>]</p>
dbaron@6470 911
dbaron@6470 912 <p>
dbaron@6470 913 For this specification to be advanced to Proposed Recommendation,
dbaron@6470 914 there must be at least two independent, interoperable implementations
dbaron@6470 915 of each feature. Each feature may be implemented by a different set of
dbaron@6470 916 products, there is no requirement that all features be implemented by
dbaron@6470 917 a single product. For the purposes of this criterion, we define the
dbaron@6470 918 following terms:
dbaron@6470 919
dbaron@6470 920 <dl>
dbaron@6470 921 <dt>independent <dd>each implementation must be developed by a
dbaron@6470 922 different party and cannot share, reuse, or derive from code
dbaron@6470 923 used by another qualifying implementation. Sections of code that
dbaron@6470 924 have no bearing on the implementation of this specification are
dbaron@6470 925 exempt from this requirement.
dbaron@6470 926
dbaron@6470 927 <dt>interoperable <dd>passing the respective test case(s) in the
dbaron@6470 928 official CSS test suite, or, if the implementation is not a Web
dbaron@6470 929 browser, an equivalent test. Every relevant test in the test
dbaron@6470 930 suite should have an equivalent test created if such a user
dbaron@6470 931 agent (UA) is to be used to claim interoperability. In addition
dbaron@6470 932 if such a UA is to be used to claim interoperability, then there
dbaron@6470 933 must one or more additional UAs which can also pass those
dbaron@6470 934 equivalent tests in the same way for the purpose of
dbaron@6470 935 interoperability. The equivalent tests must be made publicly
dbaron@6470 936 available for the purposes of peer review.
dbaron@6470 937
dbaron@6470 938 <dt>implementation <dd>a user agent which:
dbaron@6470 939
dbaron@6470 940 <ol class=inline>
dbaron@6470 941 <li>implements the specification.
dbaron@6470 942
dbaron@6470 943 <li>is available to the general public. The implementation may
dbaron@6470 944 be a shipping product or other publicly available version
dbaron@6470 945 (i.e., beta version, preview release, or “nightly build”).
dbaron@6470 946 Non-shipping product releases must have implemented the
dbaron@6470 947 feature(s) for a period of at least one month in order to
dbaron@6470 948 demonstrate stability.
dbaron@6470 949
dbaron@6470 950 <li>is not experimental (i.e., a version specifically designed
dbaron@6470 951 to pass the test suite and is not intended for normal usage
dbaron@6470 952 going forward).
dbaron@6470 953 </ol>
dbaron@6470 954 </dl>
dbaron@6470 955
dbaron@6470 956 <p>The specification will remain Candidate Recommendation for at least
dbaron@6470 957 six months.
dbaron@6470 958
dbaron@6470 959 <h2 class=no-num id="acknowledgments">
dbaron@6470 960 Acknowledgments</h2>
dbaron@6470 961
dbaron@6470 962 <p>
dbaron@6470 963 Thanks especially to the feedback from
dbaron@6470 964 H&aring;kon Wium Lie,
dbaron@6470 965 Florian Rivoal,
dbaron@6473 966 Alan Stearns,
dbaron@6470 967 and all the rest of the
dbaron@6470 968 <a href="http://lists.w3.org/Archives/Public/www-style/">www-style</a> community.
dbaron@6470 969 </p>
dbaron@6470 970
dbaron@6470 971 <h2 class=no-num id="references">
dbaron@6470 972 References</h2>
dbaron@6470 973
dbaron@6470 974 <h3 class="no-num" id="normative-references">
dbaron@6470 975 Normative references</h3>
dbaron@6470 976 <!--normative-->
dbaron@6470 977
dbaron@6470 978 <h3 class="no-num" id="other-references">
dbaron@6470 979 Other references</h3>
dbaron@6470 980 <!--informative-->
dbaron@6470 981
dbaron@6470 982 <h2 class="no-num" id="index">
dbaron@6470 983 Index</h2>
dbaron@6470 984 <!--index-->
dbaron@6470 985
dbaron@6470 986 <h2 class="no-num" id="property-index">
dbaron@6470 987 Property index</h2>
dbaron@6470 988 <!-- properties -->
dbaron@6470 989
dbaron@6470 990 </body>
dbaron@6470 991 </html>
dbaron@6470 992 <!-- Keep this comment at the end of the file
dbaron@6470 993 Local variables:
dbaron@6470 994 mode: sgml
dbaron@6470 995 sgml-declaration:"~/SGML/HTML4.decl"
dbaron@6470 996 sgml-default-doctype-name:"html"
dbaron@6470 997 sgml-minimize-attributes:t
dbaron@6470 998 sgml-nofill-elements:("pre" "style" "br")
dbaron@6470 999 sgml-live-element-indicator:t
dbaron@6470 1000 sgml-omittag:nil
dbaron@6470 1001 sgml-shorttag:nil
dbaron@6470 1002 sgml-namecase-general:t
dbaron@6470 1003 sgml-general-insert-case:lower
dbaron@6470 1004 sgml-always-quote-attributes:t
dbaron@6470 1005 sgml-indent-step:nil
dbaron@6470 1006 sgml-indent-data:t
dbaron@6470 1007 sgml-parent-document:nil
dbaron@6470 1008 sgml-exposed-tags:nil
dbaron@6470 1009 sgml-local-catalogs:nil
dbaron@6470 1010 sgml-local-ecat-files:nil
dbaron@6470 1011 End:
dbaron@6470 1012 -->
dbaron@6470 1013

mercurial