Abstract
This document points to resources related to the layout and presentation of text in languages that use the Arabic script. The target audience is developers of Web standards and technologies, such as HTML, CSS, Mobile Web, Digital Publications, and Unicode, as well as implementers of web browsers, ebook readers, and other applications that need to render text in the Arabic script.
Status of This Document
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in the W3C technical reports index at
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This document points to resources for Arabic script layout and text support on the Web and in eBooks. These resources provide information for Web technologies such as CSS, HTML and digital publications about how to support users of languages written using the Arabic script. The information here is developed in conjunction with a document that summarises gaps where the Web fails to adequately support the Arabic script.
The editor's draft of this document is being developed in the GitHub repository Language Enablement for Arabic Script languages (alreq), with contributors from the W3C Internationalization Interest Group. It is published by the Internationalization Working Group. The end target for this document is a Working Group Note.
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Some links on this page point to repositories or pages to which information will be added over time. Initially, the link may produce no results, but as issues, tests, etc. are created they will show up.
Links that have a gray color led to no content the last time this document was updated. They are still live, however, since relevant content could be added at any time. When the document is updated, links that now point to results will have their live colour restored.
This document points to resources for Arabic script layout and text support on the Web and in eBooks. These resources provide information for developers of Web technologies such as CSS, HTML and digital publications, and for application developers, about how to support languages written using the Arabic script. They include requirements, tests, GitHub discussions, type samples, and more,
A large number of languages are written using the Arabic script. Often the script is adapted in order to write a given language. For example, Arabic, Persian, and Urdu abjads write vowels using a mixture of letters and diacritics, but the diacritics are only ever used when it is necessary to clarify certain vowel sounds and are rarely found in normal text; Uighur, on the other hand, uses letters only for vowel sounds, behaving like an alphabet; languages such as Kashmiri and African ajami also use a mixture of letters and diacritics to write vowels, but the diacritics are not dropped, making their use of the script also alphabetic.
The document focuses on typographic layout issues. For a deeper understanding of the Arabic script itself and how it works see Modern Standard Arabic Orthography Notes, which includes topics such as: Phonology, Vowels, Consonants, and Numbers.
The Language enablement index points to this document and others, and provides a central location for developers and implementers to find information related to various scripts.
The W3C also has a repository with discussion threads related to the Arabic script, including requests from developers to the user community for information about how scripts/languages work, and a notification system that tracks issues related to Arabic scripts in W3C working groups. See a list of unresolved questions for Arabic script experts. Each section below points to related discussions. See also the repository home page.
In what direction does text flow along a line and across a page? (If the basic direction is right-to-left see 3.2 Bidirectional text.) If the script uses vertically oriented text, what are the requirements? What about if you mix vertical text with scripts that are normally only horizontal? Do you need a switch to use different characters in vertical vs. horizontal text? Does the browser support short runs of horizontal text in vertical lines (tate-chu-yoko in Japanese) as expected? Is the orientation of characters and the directional ordering of characters supported as needed?
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If the general inline direction is right-to-left, are there any issues when handling that? Where the inline direction of text is mixed, is this bidirectional text adequately supported? What about numbers and expressions? Do the Unicode bidi controls and HTML markup provide the support needed? Is isolation of directional runs problematic?
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How are fonts grouped into recognisable writing styles? How is each writing style used? Do the standard fallback fonts used in browsers (eg. serif, sans-serif, cursive, etc.) match expectations? Or are additional generic font styles needed? Are special font or OpenType features needed for this script that are not available? What other general, font-related issues arise? The font styles described here refer to alternative types of writing style, such as naskh vs nastaliq; for oblique, italic, and weights see instead 4.4 Letterform slopes, weights, & italics.
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If context-sensitive rendering support is needed to shape combinations of letters or position certain glyphs relative to others, is this adequately provided for? Does the script in question require additional user control features to support alterations to the position or shape of glyphs, for example adjusting the distance between the base text and diacritics, or changing the glyphs used in a systematic way? Do you need to be able to compose/decompose conjuncts or ligatures, or show characters that are otherwise hidden, etc? If text is cursive, see the separate section 4.3 Cursive text.
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- Exploratory/interactive test results (tbc)
- Exploratory/interactive test repo (tbc)
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If this script is cursive (ie. letters are generally joined up, like in Arabic, N’Ko, Syriac, etc), are there problems or needed features related to the handling of cursive text? Do cursive links break if parts of a word are marked up or styled? Do Unicode joiner and non-joiner characters behave as expected?
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What characters are used to indicate the boundaries of phrases, sentences, and sections? What about other punctuation, such as dashes, connectors, separators, etc? Are there specific problems related to punctuation or the interaction of the text with punctuation (for example, punctuation that is separated from preceding text but must not be wrapped alone to the next line)? Are there problems related to bracketing information or demarcating things such as proper nouns, etc? Some of these topics have their own sections; see also 6.2 Quotations & citations, and 6.4 Abbreviation, ellipsis & repetition.
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This is a subtopic of phrase & section boundaries that is worth handling separately. What characters are used to indicate quotations? Do quotations within quotations use different characters? What characters are used to indicate dialogue? Are the same mechanisms used to cite words, or for scare quotes, etc? What about citing book or article names? Are there any issues when dealing with quotations marks, especially when nested? Should block quotes be indented or handled specially? Do quotation marks take text direction into account appropriately?
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How are emphasis and highlighting achieved? If lines or marks are drawn alongside, over or through the text, do they need to be a special distance from the text itself? Is it important to skip characters when underlining, etc? How do things change for vertically set text?
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What characters or other methods are used to indicate abbreviation, ellipsis & repetition? Are there problems?
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- Exploratory/interactive test results (tbc)
- Exploratory/interactive test repo (tbc)
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What mechanisms, if any, are used to create *inline* notes and annotations? Are the appropriate methods for inline annotations supported for this script? The ruby spec currently specifies an initial subset of requirements for fine-tuning the typography of phonetic and semantic annotations of East Asian text, including furigana, pinyin and zhuyin fuhao systems. Is is adequate for what it sets out to do? What other controls will be needed in the future? What about other types of inline annotation, such as warichu? This section deals with inline annotation approaches. For annotation methods where a marker in the text points out to another part of the document see 8.3 Footnotes, endnotes, etc.
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This section is a catch-all for inline features that don't fit under the previous sections. It can also be used to describe in one place a set of general requirements related to inline features when those features appear in more than one of the sections above. It covers characters or methods (eg. text decoration) that are used to convey information about a range of text. Are all needed forms of highlighting or marking of text available, such as wavy underlining, numeric overbars, etc. If lines are drawn alongside, over or through the text, do they need to be a special distance from the text itself? Is it important to skip characters when underlining, etc? How do things change for vertically set text? Are there other punctuation marks that were not covered in preceding sections? Are lines correctly drawn relative to vertical text?
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Does the browser capture the rules about the way text in your script wraps when it hits the end of a line? Does line-breaking wrap whole 'words' at a time, or characters, or something else (such as syllables in Tibetan and Javanese)? What characters should not appear at the end or start of a line, and what should be done to prevent that? Is hyphenation used for your script, or something else? If hyphenation is used, does it work as expected? (Note, this is about line-end hyphenation when text is wrapped, rather than use of the hyphen and related characters as punctuation marks.)
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When text in a paragraph needs to have flush lines down both sides, does it follow the rules for your script? Does the script need assistance to conform to a grid pattern? Does your script allow punctuation to hang outside the text box at the start or end of a line? Where adjustments are need to make a line flush, how is that done? Do you shrink/stretch space between words and/or letters? Are word baselines stretched, as in Arabic? What about paragraph indents, or the need for logical alignment keywords, such as start/end, rather than left/right? Does the script indent the first line of a paragraph?
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This section is concerned with spacing that is adjusted around and between characters on a line in ways other than attempts to fit text to a given width (ie. justification). Some scripts create emphasis or other effects by spacing out the words, letters or syllables in a word. Are there requirements for this script/language that are unsupported? If spacing needs to be applied between letters and numbers, is that possible? What about space associated with punctuation, such as the gap before a colon in French? (For justification related spacing, see 7.2 Text alignment & justification.)
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Does the browser support requirements for baseline alignment between mixed scripts and in general? Are there issues related to line height or inter-line spacing, etc.? Are the requirements for baseline or line height in vertical text covered?
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- Exploratory/interactive test results (tbc)
- Exploratory/interactive test repo (tbc)
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Are there list or other counter styles in use? If so, what is the format used and can that be achieved? Are the correct separators available for use after list counters? Are there other aspects related to counters and lists that need to be addressed? Are list counters handled correctly in vertical text?
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Does the browser or ereader correctly handle special styling of the initial letter of a line or paragraph, such as for drop caps or similar? How about the size relationship between the large letter and the lines alongide? where does the large letter anchor relative to the lines alongside? is it normal to include initial quote marks in the large letter? is the large letter really a syllable? etc. Are all of these things working as expected?
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How are the main text area and ancilliary areas positioned and defined? Are there any special requirements here, such as dimensions in characters for the Japanese kihon hanmen? The book cover for scripts that are read right-to-left scripts is on the right of the spine, rather than the left. Is that provided for? When content can flow vertically and to the left or right, how do you specify the location of objects, text, etc. relative to the flow? For example, keywords 'left' and 'right' are likely to need to be reversed for pages written in English and page written in Arabic. Do tables and grid layouts work as expected? How do columns work in vertical text? Can you mix block of vertical and horizontal text correctly? Does text scroll in the expected direction? Other topics that belong here include any local requirements for things such as printer marks, tables of contents and indexes. See also 8.2 Grids & tables.
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- Exploratory/interactive test results (tbc)
- Exploratory/interactive test repo (tbc)
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As a subtopic of page layout, does the script have special requirements for character grids or for tables?
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- Exploratory/interactive test results (tbc)
- Exploratory/interactive test repo (tbc)
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Are vertical form controls well supported? In right-to-left scripts, is it possible to set the base direction for a form field? Is the scroll bar on the correct side? etc. Are there other aspects related to user interaction that need to be addressed?
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- Exploratory/interactive test results (tbc)
- Exploratory/interactive test repo (tbc)
- Gap analysis
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