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Braille Patterns

(Redirected from Braille patterns)
For the meaning of braille dot patterns, see English Braille.

The Unicode block Braille Patterns (U+2800..U+28FF) contains all 256 possible patterns of an 8-dot braille cell, thereby including the complete 6-dot cell range.[3] In Unicode, a braille cell does not have a letter or meaning defined. For example, Unicode does not define U+2817 ⠗ BRAILLE PATTERN DOTS-1235 to be "R".

Braille Patterns
RangeU+2800..U+28FF
(256 code points)
PlaneBMP
ScriptsBraille
Assigned256 code points
Unused0 reserved code points
Source standardsISO 11548-1
Unicode version history
3.0 (1999)256 (+256)
Unicode documentation
Code chart ∣ Web page
Note: [1][2]
⠝
This article contains Unicode Braille characters. Without proper rendering support, you may see question marks, boxes, or other symbols instead of Braille characters.

Independent script

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In themselves, braille letters do not belong to any print script, but constitute a distinct braille script. The same braille letter can be used to transcribe multiple scripts, e.g. Latin, Cyrillic, Greek and even elements of Chinese characters, as well as digits. Thus while U+2813 ⠓ BRAILLE PATTERN DOTS-125 transcribes the letter h of the Latin script, as well as the digit 8, it transcribes ᄐ t- of Korean hangul and り ri of Japanese kana.

The Unicode character property of braille characters is set to "So" (Symbol, other) rather than to "Lo" (Letter, other). The ISO 15924 script code for braille "Brai".[3]

Identifying, naming and ordering

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Braille dot numbering
 
Hexadecimal value of braille dots

The coding is in accordance with ISO/TR 11548-1 Communication aids for blind persons.[3] Unicode uses the standard dot-numbering 1 to 8. Historically only the 6-dot cell was used in braille. The lower two dots were added later, which explains the irregular numbering 1-2-3-7 in the left column and 4-5-6-8 in the right column. Where dots 7 and 8 are not raised, there is no distinction between 6-dot and 8-dot definitions.

The Unicode name of a specific pattern mentions the raised dots: U+2813 ⠓ BRAILLE PATTERN DOTS-125 has dots 1, 2 and 5 raised. By exception, the zero dot raised pattern is named U+2800 ⠀ BRAILLE PATTERN BLANK.[4]

In the 8-dot cell each dot individually can be raised or not. That creates 28=256 different patterns. By mapping each of the eight dots to a bit in a byte (in a little-endian order), and by defining "0"/"1" for not raised/raised per bit, every specific pattern generates an identifying binary number. So the pattern with dots 1-2-5 raised would yield (00010011)2, equivalent to (13)16 or (19)10.

The mapping can also be computed by adding together the hexadecimal values, seen at right, of the dots raised. So the pattern with dots 1-2-5 raised would yield 116+216+1016 = 1316. Whether computed directly in hexadecimal, or indirectly via binary, the result is added to 280016, the offset for the Braille Patterns Unicode block.

Unicode: Braille Pattern encoding examples
Braille symbol ⠓ ⣇ ⣿
Unicode character U+2813 U+28C7 U+28FF
Name BRAILLE PATTERN DOTS-125 BRAILLE PATTERN DOTS-12378 BRAILLE PATTERN DOTS-12345678
Dot numbers available 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
Dot raised=1 1 1 0 0 1 0 0 0 1 1 1 0 0 0 1 1 1 1 1 1 1 1 1 1
Reverse order
(lowest value right, as in decimal notation) 		0 0 0 1 0 0 1 12 1 1 0 0 0 1 1 12 1 1 1 1 1 1 1 12
Hex value of dots 10+2+116 80+40+4+2+116 80+40+20+10+8+4+2+116
Total hexadecimal value 1316 C716 FF16
Into block,
offset U+280016 		280016+1316=U+2813 280016+C716=U+28C7 280016+FF16=U+28FF

There is no regular mapping to the braille ASCII numbering.

Colloquial names

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The Unicode names of braille dot patterns are not the same as what many English speakers would use colloquially. In particular, Unicode names use the word dots in the plural even when only one dot is listed: thus Unicode says braille pattern dots-5 when most English-speaking users of braille would simply say "braille dot 5" or just "dot 5".

In addition, some English-speaking users of braille use the word "and" when listing only two dots. Thus braille pattern dots-45 would be spoken as "braille dots 4 and 5". The word "and" is not always used when listing many dots however.

Block

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Braille was added to the Unicode Standard in September, 1999 with the release of version 3.0.

When using punching, the filled (black) dots are to be punched.

The Unicode block for braille is U+2800 ... U+28FF:

Braille Patterns[1]
Official Unicode Consortium code chart (PDF)
  0 1 2 3 4 5 6 7 8 9 A B C D E F
U+280x ⠀ ⠁ ⠂ ⠃ ⠄ ⠅ ⠆ ⠇ ⠈ ⠉ ⠊ ⠋ ⠌ ⠍ ⠎ ⠏
U+281x ⠐ ⠑ ⠒ ⠓ ⠔ ⠕ ⠖ ⠗ ⠘ ⠙ ⠚ ⠛ ⠜ ⠝ ⠞ ⠟
U+282x ⠠ ⠡ ⠢ ⠣ ⠤ ⠥ ⠦ ⠧ ⠨ ⠩ ⠪ ⠫ ⠬ ⠭ ⠮ ⠯
U+283x ⠰ ⠱ ⠲ ⠳ ⠴ ⠵ ⠶ ⠷ ⠸ ⠹ ⠺ ⠻ ⠼ ⠽ ⠾ ⠿
(end of 6-dot cell patterns)
U+284x ⡀ ⡁ ⡂ ⡃ ⡄ ⡅ ⡆ ⡇ ⡈ ⡉ ⡊ ⡋ ⡌ ⡍ ⡎ ⡏
U+285x ⡐ ⡑ ⡒ ⡓ ⡔ ⡕ ⡖ ⡗ ⡘ ⡙ ⡚ ⡛ ⡜ ⡝ ⡞ ⡟
U+286x ⡠ ⡡ ⡢ ⡣ ⡤ ⡥ ⡦ ⡧ ⡨ ⡩ ⡪ ⡫ ⡬ ⡭ ⡮ ⡯
U+287x ⡰ ⡱ ⡲ ⡳ ⡴ ⡵ ⡶ ⡷ ⡸ ⡹ ⡺ ⡻ ⡼ ⡽ ⡾ ⡿
U+288x ⢀ ⢁ ⢂ ⢃ ⢄ ⢅ ⢆ ⢇ ⢈ ⢉ ⢊ ⢋ ⢌ ⢍ ⢎ ⢏
U+289x ⢐ ⢑ ⢒ ⢓ ⢔ ⢕ ⢖ ⢗ ⢘ ⢙ ⢚ ⢛ ⢜ ⢝ ⢞ ⢟
U+28Ax ⢠ ⢡ ⢢ ⢣ ⢤ ⢥ ⢦ ⢧ ⢨ ⢩ ⢪ ⢫ ⢬ ⢭ ⢮ ⢯
U+28Bx ⢰ ⢱ ⢲ ⢳ ⢴ ⢵ ⢶ ⢷ ⢸ ⢹ ⢺ ⢻ ⢼ ⢽ ⢾ ⢿
U+28Cx ⣀ ⣁ ⣂ ⣃ ⣄ ⣅ ⣆ ⣇ ⣈ ⣉ ⣊ ⣋ ⣌ ⣍ ⣎ ⣏
U+28Dx ⣐ ⣑ ⣒ ⣓ ⣔ ⣕ ⣖ ⣗ ⣘ ⣙ ⣚ ⣛ ⣜ ⣝ ⣞ ⣟
U+28Ex ⣠ ⣡ ⣢ ⣣ ⣤ ⣥ ⣦ ⣧ ⣨ ⣩ ⣪ ⣫ ⣬ ⣭ ⣮ ⣯
U+28Fx ⣰ ⣱ ⣲ ⣳ ⣴ ⣵ ⣶ ⣷ ⣸ ⣹ ⣺ ⣻ ⣼ ⣽ ⣾ ⣿
Notes
1.^ As of Unicode version 16.0

Font differences

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When showing braille graphically in printed instruction manuals, it can be useful to indicate the dots that are not punched, especially if a single braille cell of only one or two punched dots is shown out of context: in this case it might otherwise be difficult to judge the vertical alignment of the dots and tell the difference between, say, dots 2 and 4 versus dots 3 and 5.

The current Unicode charts, and some fonts, use empty circles to indicate dots that are not punched. This does not always render very clearly: if the circle outlines are printed heavily then it can be difficult to tell at a glance whether the dot is filled in or not. The braille package for LaTeX (and several printed publications such as the printed manual for the new international braille music code) show unpunched dots as very small dots (much smaller than the filled-in dots) rather than circles, and this tends to print better.

Some braille fonts do not indicate unpunched dots at all. Additionally, some Linux braille fonts (e.g. GNU Unifont and the DejaVu fonts) use small squares instead of small circles to indicate dots.[5]

Other uses

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The Braille Pattern characters are commonly[6][failed verification] used in terminal applications as a way to draw multiple pixels per character.

History

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The following Unicode-related documents record the purpose and process of defining specific characters in the Braille Patterns block:

Version Final code points[a] Count UTC ID L2 ID WG2 ID Document
3.0 U+2800..28FF 256 X3L2/90-064 Extracts from "A Proposal for Funding the Programs of Braille Research and Literacy", 1990-01-01
X3L2/91-085 TC 173 Proposals for new work items for Braille Coding, 1991-03-20
X3L2/92-039 Bishop, Avery (1991-10-29), The long awaited draft reply on Braille symbol encoding
N1093 Shibano, Kohji (1994-12-26), Braille Letters
N1203 Umamaheswaran, V. S.; Ksar, Mike (1995-05-03), "6.1.3.3", Unconfirmed minutes of SC2/WG2 Meeting 27, Geneva
X3L2/95-114 N1279 Braille letters (addition request), 1995-10-27
N1303 (html, doc) Umamaheswaran, V. S.; Ksar, Mike (1996-01-26), "8.14 Braille", Minutes of Meeting 29, Tokyo
X3L2/95-125 Duran, Peter (1990-05-24), A Proposal for Funding the Programs of Braille Research and Literacy
UTC/1996-002 Aliprand, Joan; Hart, Edwin; Greenfield, Steve (1996-03-05), "Braille", UTC #67 Minutes
UTC/1996-007 Hart, Edwin (1996-03-07), Contribution on Encoding Braille in ISO/IEC 10646
N1342 Sato, Takayuki K. (1996-03-19), Braille letters (confirmation of request)
N1339 Ksar, Mike (1996-03-28), Liaison Letter on Braille to ISO/TC137 Secretariat
N1345 Hart, Edwin (1996-04-01), Initial comments on encoding Braille into ISO/IEC 10646
N1353 Umamaheswaran, V. S.; Ksar, Mike (1996-06-25), "8.9", Draft minutes of WG2 Copenhagen Meeting # 30
UTC/1996-027.2 Greenfield, Steve (1996-07-01), "K. Braille Proposal", UTC #69 Minutes (PART 2)
N1409R Braille Symbols, 1996-08-12
N1453 Ksar, Mike; Umamaheswaran, V. S. (1996-12-06), "8.9", WG 2 Minutes - Quebec Meeting 31
L2/97-047 N1541 Everson, Michael (1997-03-11), Proposed pDAM text for Braille
N1588 DIS 11 548-1 - Communication aids for blind persons Part 1: Braille identifiers and shift marks - General guidelines, 1997-06-23
N1588.1 DIS 11 548-2 - Communication aids for blind persons Part 2: Latin alphabet based character sets
L2/97-157 N1612 Report of ad-hoc group on Braille encoding, 1997-07-01
L2/97-288 N1603 Umamaheswaran, V. S. (1997-10-24), "8.4", Unconfirmed Meeting Minutes, WG 2 Meeting # 33, Heraklion, Crete, Greece, 20 June – 4 July 1997
L2/98-136 N1770 Paterson, Bruce (1998-04-06), Revised Text of 10646-1/FPDAM 16: Amendment 16: Braille Patterns
L2/98-286 N1703 Umamaheswaran, V. S.; Ksar, Mike (1998-07-02), "6.2.2 FPDAM-16 - Braille patterns", Unconfirmed Meeting Minutes, WG 2 Meeting #34, Redmond, WA, USA; 1998-03-16--20
  1. ^ Proposed code points and characters names may differ from final code points and names

References

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  1. ^ "Unicode character database". The Unicode Standard. Retrieved 2023-07-26.
  2. ^ "Enumerated Versions of The Unicode Standard". The Unicode Standard. Retrieved 2023-07-26.
  3. ^ a b c Unicode Chapter 15, section 15.10
  4. ^ Unicode chart U+2800, braille patterns
  5. ^ "Braille Pattern Dots-1358 (U+2895) Font Support". fileformat.info. Retrieved December 7, 2014.
  6. ^ "Iirelu/Braillify". GitHub. 22 July 2021.
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