"युनिकोड" का संशोधनहरू बिचको अन्तर

सा r2.5.2) (रोबोट ले परिवर्तन गर्दै: fa:یونی‌کد
सा स्वचालित हिज्जे सम्पादन, replaced: मा → मा (71), हरु → हरू (2)
पङ्क्ति १:
{{Table Unicode}}
'''युनिकोड''' कम्प्युटरको एक अन्तर्राष्ट्रिय गुणस्तर हो जसको उदेश्य मानिसले कम्प्युटरमा भण्डारण गर्न चाहने हरेक दस्तावेजका लिपिलाई [[सङ्केतन]] (encode) गर्ने माध्यम प्रदान गर्नु हो। This includes all [[:en:Writing system|script]]s still माstillमा active use today, many scripts known only by [[:en:scholar|scholar]]s, र [[:en:symbol|symbol]]s which do not strictly represent scripts, like [[:en:mathematics|mathematics]], [[:en:linguistics|linguistics]] र [[:en:APL programming language|APL]].
 
The creation of युनिकोड is an ambitious [[:en:project|project]] to replace existing [[:en:character encoding|character set]]s, many of which are short माshortमा size र problematic माproblematicमा [[:en:multilingual|बहुभाषीय]] environments. Despite technical problems र limitations र criticism on process, today युनिकोड is considered the most complete character set र one of the largest, र has become the dominant encoding scheme माschemeमा [[:en:internationalization‍|अन्तराष्ट्रियकरण]] of [[:en:Computer software|software]] र multilingual environments. Many recent standards such as [[:en:XML|XML]], as well as [[:en:system software‍|system software]] such as [[:en:operating system|operating system]]s, have adopted युनिकोड as an underlying scheme to represent text.
 
== Origin र development ==
 
It is the explicit aim of युनिकोड to transcend the limitations of traditional [[:en:character encoding|character encoding]]s such as those defined by the [[:en:ISO 8859|ISO 8859]] standard, which are used माusedमा the various countries of the world, but are largely incompatible with each other. One problem with traditional character encodings is that they allow for [[:en:bilingual|bilingual]] कम्प्युटर processing (usually [[:en:Roman character|रोमन अक्षर]]हरुहरू र the local language), but not for multilingual कम्प्युटर processing (कम्प्युटर processing of arbitrary languages mixed with each other).
 
युनिकोड मायुनिकोडमा intent encodes the underlying characters र not variant [[:en:glyph|glyph]]s for such characters. In the case of [[:en:Chinese character‍‍|चाइनिज अक्षरहरुअक्षरहरू]]s, this sometimes leads to controversies over what is the underlying character र what is the variant glyph (see [[:en:Han unification|Han unification]]).
 
युनिकोड's role माroleमा text-processing is to provide a unique code point — not a glyph — for each character. In other words, युनिकोड is used to represent a character माcharacterमा an abstract way, र leaves the visual rendering (size, shape or style) to another program, such as a [[:en:web browser|वेब ब्राउजर]] or [[:en:word processor|word processor]].
 
This simple aim is greatly complicated by another aim, which is to provide lossless conversion amongst different existing encodings माencodingsमा order to ease the transition.
 
The युनिकोड standard also includes a number of related items, such as character properties, text normalisation forms, र bidirectional display order (for the correct display of text containing both right-to-left scripts, such as [[:en:Arabic‍‍|अरबी]] or [[:en:Hebrew language|हेब्रु]], र left-to-right scripts).
 
In [[1997]] a proposal was made by [[:en:Michael Everson|माइकल इभरसन्]] to encode the characters of the [[Klingon language]] मा Plane 1 of [[ISO 10646|ISO/IEC 10646-2]]. The proposal was rejected माrejectedमा [[2001]] as "inappropriate for encoding" — not because the proposal was technically faulty, but because users of Klingon normally read र write र exchange data माdataमा [[Latin]] transliteration. The [[Elves (Middle-earth)|elvish]] scripts [[Tengwar]] र [[Cirth]] from [[J. R. R. Tolkien]]'s [[Middle-earth]] setting were proposed for inclusion माinclusionमा Plane 1 मा1मा [[1993]]. The draft was withdrawn to incorporate changes suggested by [[Tolkienist]]s, र is as of [[2004]] still under consideration.
 
== Mapping र encodings ==
=== Standard ===
 
The [[युनिकोड Consortium]], based माbasedमा [[California]], is the organization that develops the युनिकोड standard. It is an organization open to any company or individual willing to pay the membership dues. Members include virtually all of the main कम्प्युटर software र hardware companies with any interest माinterestमा text processing standards, such as [[Apple Computer]], [[Microsoft]], [[International Business Machines|IBM]], [[Xerox]], [[Hewlett-Packard|HP]], [[Adobe Systems]] र many others.
 
The Consortium first published ''The युनिकोड Standard'' (ISBN 0-321-18578-1) मा [[1991]], र continues to develop standards based on that original work. युनिकोड was developed माdevelopedमा conjunction with the [[ISO|International Organization for Standardization]] र it shares its character repertoire with [[ISO/IEC 10646]]. युनिकोड र ISO/IEC 10646 are equivalent as character encodings, but ''The युनिकोड Standard'' contains much more information for implementers, covering, मा depth, topics such as bitwise encoding, [[collation]], र rendering, र enumerating a multitude of character properties, including those needed for [[BiDi]] support. The two standards also have slightly different terminology.
 
==== युनिकोड revision history ====
पङ्क्ति ३९:
=== Storage transfer र processing ===
 
So far, it has only been said that युनिकोड is a means to assign a unique number for all characters used by [[human]]s माsमा written language. How these numbers are stored माstoredमा text processing is another matter; problems result from the fact that much [[software]] मा the West has so far been written to deal with 8-bit character encodings only, र युनिकोड support has only been added slowly माslowlyमा recent years. Similarly, मा the East the double-byte character encodings cannot even माevenमा principle encode more than 65,536 characters, र मारमा practice the limit imposed by the architectures chosen is much lower. This is not enough for the needs of scholars of the [[Chinese language]] alone.
 
The internal logic of much 8-bit legacy software typically permits only 8 bits for each character, making it impossible to use more than 256 code points without special processing, र 16-bit software is limited to some tens of thousands of characters, while युनिकोड is already up to more than 90,000 encoded characters. Several mechanisms have therefore been suggested to implement युनिकोड; which one is chosen depends on available storage space, [[source code]] compatibility, र interoperability with other systems.
 
The mapping methods are called the UTF (युनिकोड Transformation Format) र UCS (Universal Character Set) encodings. Among them are [[UTF-32]], [[UCS-4]], [[UTF-16]], [[UCS-2]], [[UTF-8]], [[UTF-EBCDIC]] र [[UTF-7]]. The numbers indicate the number of bits माbitsमा one unit, for UTF encodings, or bytes, for UCS encodings. In UTF-32 or UCS-4, one unit is enough for any character; मा the other cases, a variable number of units is used for each character. UTF-8 is the de-facto standard encoding for interchange of युनिकोड text with UTF-16 र UTF-32 being used mainly for internal processing.
 
The युनिकोड [[Byte Order Mark|byte order mark]] (BOM) is specified for use at the beginnings of text files माfilesमा UCS-2 र UTF-16 encodings. It has been adopted by some software developers for other encodings, including UTF-8, which does not need an indication of byte order. In this case it is an attempt to mark the file as containing युनिकोड text. The BOM is code point <code>U+FEFF</code>, which has the important property of being unambiguously interpretable regardless of which युनिकोड encoding is used. The units <code>FE</code> र <code>FF</code> never appear माappearमा [[UTF-8]], <code>U+FFFE</code> (the result of byte-swapping <code>U+FEFF</code>) is not a legal character, र <code>U+FEFF</code> is the Zero-Width No-Break Space (a character with no appearance र no effect other than preventing formation of [[ligature (typography)|ligatures]]). The same character converted to UTF-8 becomes the byte sequence <code>EF BB BF</code>.
 
{{See also|Mapping of युनिकोड characters}}
पङ्क्ति ५१:
=== Ready-made vs. composite characters ===
 
युनिकोड includes a mechanism for modifying character shape र so greatly extending the supported glyph repertoire. This is the use of [[combining diacritical mark]]s. They are inserted after the main character (it is possible to stack several combining diacritics over the same character). However, for reasons of compatibility, युनिकोड also includes a large quantity of [[precomposed character]]s. So माSoमा many cases there are many ways of encoding the same character. To deal with this, युनिकोड provides the mechanism of [[canonical equivalence]].
 
The situation with [[Hangul]] is similar. युनिकोड provides the mechanism for composing Hangul syllables with [[Hangul Jamo]]. However, the precomposed Hangul syllables (11,172 of them) are also provided.
 
The [[CJK]] ideographs currently are encoded only माonlyमा their precomposed form. Still, most of those ideographs are evidently made up of simpler elements, so माsoमा principle it would be possible to decompose them just as it is done with [[Hangul]]. This would greatly reduce the number of required codepoints, while allowing the display of virtually every conceivable ideograph (and so doing away with all problems of the [[Han unification]]). A similar idea is used for some [[input method]]s, such as [[Cangjie method|Cangjie]] र [[Wubi method|Wubi]]. However, attempts to do this for character encoding have stumbled over the fact that ideographs are not as simply decomposed or as regular as they seem.
 
Combining marks, like the complex script shaping required to properly render [[Arabic]] text र many other scripts, are usually dependent on complex font technologies, like [[OpenType]] (by Adobe र [[Microsoft]]), Graphite (by [[SIL International]]), र [[Apple Advanced Typography|AAT]] (by [[Apple Computer|Apple]]), by which a font designer includes instructions माinstructionsमा a font telling software how to properly output different character sequences. Another method sometimes employed माemployedमा [[fixed-width]] fonts is to place the combining mark's glyph before its own left [[sidebearing]]; this method, however, only works for some diacritics र stacking will not occur properly.
 
[[As of 2004]], most software still cannot reliably handle many features not supported by older font formats, so combining characters generally will not work correctly. Hypothetically, {{युनिकोड|ḗ}} (precomposed e with macron र acute above) र {{युनिकोड|ḗ}} (e followed by the combining macron above र combining acute above) are identical माidenticalमा appearance, both giving an [[e]] with [[macron]] र [[acute accent]], but appearance can vary greatly across software applications.
 
Also underdots, as needed माneededमा Indic [[Romanization]], will often be placed incorrectly or worse. Sample:
:{{युनिकोड|ṃ - ṇ - ḷ}}
Of course, this is माisमा fact not a weakness माweaknessमा युनिकोड itself, but only uncovers gaps माgapsमा rendering technology र fonts.
 
=== Issues ===
 
Some people, mostly माmostlyमा Japan, oppose युनिकोड मायुनिकोडमा general, claiming technical limitations र political problems माproblemsमा process, which people working on the युनिकोड standard claim are simply misunderstandings of the युनिकोड standard र the process by which it was created. The most common mistake, according to this view, is confusion between abstract [[characters]] र their highly variable visual forms ([[glyphs]]). On the other hand, whereas Chinese can readily read most types of glyphs used by Japanese or Koreans, Japanese often can recognize only a particular variant. The strongest denunciation of युनिकोड is at [http://www.hastingsresearch.com/net/04-unicode-limitations.shtml] (also see a response, [http://slashdot.org/features/01/06/06/0132203.shtml]) For example, opponents of युनिकोड sometimes claim even now that it cannot handle more than 65,535 characters, a limitation that was removed माremovedमा युनिकोड 2.0. युनिकोड has been decried as a plot against Asian cultures perpetrated by Westerners with no understanding of the characters as used माusedमा Chinese, Korean, र Japanese, मा spite of the presence of a majority of experts from all three countries माcountriesमा the [[Ideographic Rapporteur Group]]. The IRG advises the consortium र ISO on additions to the repertoire र on [[Han unification]], the identification of forms माformsमा the three languages which will be treated as stylistic variations of the same historical character. This unification is one of the most controversial aspects of युनिकोड.
 
युनिकोड is criticized for failing to allow for older र alternate forms of [[kanji]], which, it is said, complicates the processing of ancient Japanese र uncommon Japanese names, although it follows the recommendations of Japanese scholars of the language र of the Japanese government. There have been several attempts to create an alternative to युनिकोड. [http://www-106.ibm.com/developerworks/unicode/library/u-secret.html] Among them are [[TRON]] (although it is not widely adopted माadoptedमा Japan, some, particularly those who need to handle historical Japanese text, favor this), [[UTF-2000]] र [[Giga Character Set]] (GCS). It is true that many older forms were not included माincludedमा early versions of the युनिकोड standard, but युनिकोड 4.0 contains more than 90,000 Han characters, far more than any dictionary or any other standard, र work continues on adding characters from the early literature of China, Korea, र Japan.
 
[[Thai language]] support has been criticized for its illogical ordering of Thai characters. This complication is due to युनिकोड inheriting the [[TIS-620|Thai Industrial Standard 620]], which worked माworkedमा the same way. This ordering problem complicates the युनिकोड collation process [http://www-106.ibm.com/developerworks/unicode/library/u-secret.html].
 
== युनिकोड मायुनिकोडमा use ==
=== Operating systems ===
 
पङ्क्ति ८०:
=== E-mail ===
 
[[MIME]] defines two different mechanisms for encoding non-ASCII characters माcharactersमा [[इमेल|e-mail]], depending on whether the characters are माareमा e-mail headers such as the "Subject:" or माorमा the text body of the message. In both cases, the original character set is identified as well as a transfer encoding. For e-mail transmission of युनिकोड the UTF-8 character set र the [[Base64]] transfer encoding are recommended. The details of the two different mechanisms are specified माspecifiedमा the MIME standards र are generally hidden from users of e-mail software.
 
The adoption of युनिकोड मायुनिकोडमा [[इमेल|e-mail]] has been very slow. Most East-Asian text is still encoded माencodedमा a local encoding such as [[Shift-JIS]], र many commonly used e-mail programs still cannot handle युनिकोड data correctly, if they have some support at all. This situation is not expected to change माchangeमा the foreseeable future.
 
=== Web ===
पङ्क्ति ८८:
Recent web browsers display web pages using युनिकोड if an appropriate [[typeface|font]] is installed (see [[Unicode र HTML]]).
 
Although syntax rules may affect the order माorderमा which characters are allowed to appear, both HTML 4.0 र XML 1.0 documents are, by definition, comprised of characters from the entire range of युनिकोड code points, minus only a handful of disallowed control characters र the permanently-unassigned code points D800-DFFF, any code point ending माendingमा FFFE or FFFF र any code point above 10FFFF. These characters manifest either directly as [[byte]]s according to document's encoding, if the encoding supports them, or they may be written as numeric character references based on the character's युनिकोड code point, as long as the document's encoding supports the digits र symbols required to write the references (all encodings approved for use on the Internet do). For example, the references <code>Δ</code> <code>Й</code> <code>ק</code> <code>م</code> <code>๗</code> <code>あ</code> <code>叶</code> <code>葉</code> <code>냻</code> (or the same numeric values expressed माexpressedमा hexadecimal, with <code>&amp;#x</code> as the prefix) display on your browser as Δ, Й, ק, م, ๗, あ, 叶, 葉 र 냻—if you have the proper fonts, these symbols look like the [[Greek alphabet|Greek]] capital letter "Delta", [[Cyrillic alphabet|Cyrillic]] capital letter "Short I", [[Arabic alphabet|Arabic]] letter "Meem", [[Hebrew alphabet|Hebrew]] letter "Qof", [[Thai language|Thai]] [[numeral]] 7, [[Japanese language|Japanese]] [[Hiragana]] "A", [[simplified Chinese]] "[[Leaf]]", [[traditional Chinese]] "Leaf", र [[Korean language|Korean]] [[Hangul]] syllable "Nyaelh", respectively.
 
=== Fonts ===
पङ्क्ति ९४:
Free र retail fonts based on युनिकोड are common, since first [[TrueType]] र now [[OpenType]] support युनिकोड. These font formats map युनिकोड code points to glyphs.
 
There are thousands of fonts on the market, but fewer than a dozen fonts attempt to support the majority of युनिकोड's character repertoire; these fonts are sometimes described as pan-युनिकोड. Instead, युनिकोड based fonts typically focus on supporting only basic ASCII र particular scripts or sets of characters or symbols. There are several reasons for this: applications र documents rarely need to render characters from more than one or two writing systems; fonts tend to be resource hogs माhogsमा computing environments; र operating systems र applications are becoming increasingly intelligent माintelligentमा regard to obtaining glyph information from separate font files as they are needed. Furthermore, it is a monumental task to design a consistent set of rendering instructions for tens of thousands of glyphs; such a venture passes the point of [[diminishing returns]] for most typefaces.
 
युनिकोड characters which cannot be rendered are most often displayed as an open rectangle only, to indicate the position of the unrecognized character. Some attempts have been made to provide more information about these characters. The Apple ''[[LastResort]]'' font will display a substitute glyph indicating the युनिकोड range of the character र the [[SIL International|SIL]] [[Unicode fallback font]] will display a box showing the hexadecimal scalar value of the character.
पङ्क्ति ११०:
Word 2003 also allows for entering युनिकोड characters by spelling out the code first, e.g. 014B for the 'ng'-symbol र then hitting 'Alt' plus 'X' to substitute the string to the left by its युनिकोड character.
 
Macintosh users have a similar feature with an input method called 'Unicode Hex Input', मा [[Mac OS X]] र मारमा [[Mac OS]] 8.5 र later: hold down the Option key, र type the four-hex-digit युनिकोड code point. Handling of code-points above 0xFFFF is done by entering a [[UTF-16|surrogate pair]]; they will be converted into a single character automatically. Mac OS X (version 10.2 र newer) also has a 'Character Palette', which allows users to visually select any युनिकोड character from a table organized numerically, by युनिकोड block, or by a selected font's available characters.
 
[[GNOME|Gnome2]] follows [[ISO 14755]]. Hold down Ctrl र Shift र enter the hexadecimal युनिकोड value.
 
The [[Opera (web browser)|Opera web browser]] मा version 7.5 र over allows users to enter any युनिकोड character directly into a text field by typing its hexadecimal code, selecting it, र pressing alt+x.
 
== See also ==
पङ्क्ति १२५:
** [http://www.unicode.org/charts/ Code Charts] ([[portable document format|PDF]])
* [http://www.macchiato.com/unicode/charts.html UTF-8, UTF-16, UTF-32 Code Charts] र a [http://www-atm.physics.ox.ac.uk/user/iwi/charmap.html character map] ([[JavaScript]])
* [http://www.eki.ee/letter/ The Letter Database] Uses forms to present groups माgroupsमा list or grid format by [[hexadecimal]].
* [http://www.decodeunicode.org/ DecodeUnicode - Unicode Wiki, 50.000 gifs र information about each character]
* [http://www.cl.cam.ac.uk/~mgk25/ucs/examples/ Example text files using Unicode]
* [http://www.lazytools.com/unicode-ascii/ Unicode special character map] is similar to the Windows version. Click a symbol to obtain either the named or numeric code for HTML.
* [[Michael Everson]]'s [http://www.unicode.org/notes/tn4/everson-iuc21pap.pdf "Leaks मा the Unicode pipeline: script, script, script…"] PDF 2MB
* [http://www.evertype.com/standards/csur/ ConScript Unicode Registry] a project to standardize part of the Private Use Area for use with [[artificial script]]s र artificial languages. An explanation of how to propose character names माnamesमा Unicode is available here.
* [http://www-106.ibm.com/developerworks/unicode/library/u-secret.html The secret life of Unicode] "A peek at Unicode's soft underbelly" Describes problems requiring resolution. Includes links to Unicode resources.
* Tim Bray's [http://www.tbray.org/ongoing/When/200x/2003/04/26/UTF Characters vs Bytes] explains how the different encodings work.
* [http://www.joelonsoftware.com/articles/Unicode.html The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode र Character Sets (No Excuses!)] by [[Joel Spolsky]]
* [http://www.alanwood.net/unicode/ Alan Wood's Unicode Resources] Contains lists of word processors with Unicode capability; characters are grouped by type; characters are presented माpresentedमा lists, not grids.
* [[Font]]s र tools:
** [http://www.cl.cam.ac.uk/~mgk25/ucs-fonts.html Unicode fonts र tools] for the [[X Window System]]
पङ्क्ति १४२:
** [http://www.icu-project.org/ International Components for Unicode (ICU)] An open source set of libraries that provide robust र full-featured Unicode services for your applications on a wide variety of platforms.
** [http://www.joelonsoftware.com/articles/Unicode.html The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode र Character Sets (No Excuses!)] by [[Joel Spolsky]] of JoelonSoftware.com
** [http://freedesktop.org/wiki/Software_2futf_2d8 Freedesktop.Org’s Project UTF-8]’s purpose is to document र promote proper Unicode support माsupportमा free र Open Source software.
* Seeing [http://www.ianalbert.com/misc/unichart.php the entirety of Unicode printed out] as a single large poster gives a good feel for the size of the code.
 
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