Braille Unicode block
Encyclopedia
In Unicode
, Braille
is represented in a block
called Braille Patterns (U+2800..U+28FF). The block contains all 256 possible patterns of an 8-dot Braille cell, thereby including the complete 6-dot cell range.
"Brai", for Braille. This way searching users and programs are led to the right place.
The Unicode name of a specific pattern mentions the raised dots: has dots 1, 2 and 5 raised. By exception, the zero dot raised pattern is named .
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 low endian
order), and by defining "0"/"1" for not raised/raised per bit, every specific pattern generates a 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.
There is no regular mapping to the Braille ASCII
numbering.
Some English users of Braille additionally use the word "and" when listing only two dots. Thus would be spoken as "Braille dots 4 and 5". The word "and" is not always used when listing many dots however.
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:
The current Unicode charts, and Mac OS X (as of 10.6), 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 use small squares instead of small circles to indicate dots.
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
, Braille
Braille
The Braille system is a method that is widely used by blind people to read and write, and was the first digital form of writing.Braille was devised in 1825 by Louis Braille, a blind Frenchman. Each Braille character, or cell, is made up of six dot positions, arranged in a rectangle containing two...
is represented in a block
Unicode block
In Unicode, a block is defined as one contiguous range of code points. Blocks are named uniquely and have no overlap. They may be defined with the starting and ending code points. The block explicitly can include code points that are unassigned and non-characters. Code points not belonging to any...
called Braille Patterns (U+2800..U+28FF). The block contains all 256 possible patterns of an 8-dot Braille cell, thereby including the complete 6-dot cell range.
Symbols, not a script
In Unicode the Braille characters are not defined into any script. That is, the patterns are available as symbols, without connection to an alphabetic letter or a number. This is because the same symbol can be used in multiple scripts, e.g. as a Latin character, a Vietnamese character, a Chinese character and a digit. For example: while is defined, there is no reference to the letter "H", as exists in basic Latin Braille. In other Braille languages the same pattern ⠓ can have a different meaning; in the original Latin Braille the same ⠓ can represent digit "8". For this reason (a dot-pattern is not a letter), Unicode declares that strictly spoken, Braille patterns are 'symbols', not a 'script'. The General Property is "So" (Symbol, other), not "Lo" (Letter, other). Although beyond that declaration, Braille is treated as a script multiple places. E.g. the character property "Script" for the 256 Braille code points is ISO 15924ISO 15924
ISO 15924, Codes for the representation of names of scripts, defines two sets of codes for a number of writing systems . Each script is given both a four-letter code and a numeric one....
"Brai", for Braille. This way searching users and programs are led to the right place.
Identifying, naming and ordering
The coding is in accordance with ISO/TR 11548-1 Communication aids for blind persons. 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: has dots 1, 2 and 5 raised. By exception, the zero dot raised pattern is named .
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 low endian
Endianness
In computing, the term endian or endianness refers to the ordering of individually addressable sub-components within the representation of a larger data item as stored in external memory . Each sub-component in the representation has a unique degree of significance, like the place value of digits...
order), and by defining "0"/"1" for not raised/raised per bit, every specific pattern generates a 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.
| Braille symbol | style="font-family: Charis SIL, Doulos SIL, DejaVu Sans;">⠓ | style="font-family: Charis SIL, Doulos SIL, DejaVu Sans;">⣇ | style="font-family: Charis SIL, Doulos SIL, DejaVu Sans;">⣿ |
| 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 |
| Binary value (by reversing order) |
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=281316 |
280016+C716=28C716 |
280016+FF16=28FF16 |
There is no regular mapping to the Braille ASCII
Braille ASCII
Braille ASCII is a subset of the ASCII character set which uses 64 of the printable ASCII characters to represent all possible dot combinations in six-dot Braille...
numbering.
Colloquial names
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 in the plural even when only one dot is listed: thus Unicode says when most English users of Braille would simply say "Braille dot 5" or just "dot 5".Some English users of Braille additionally use the word "and" when listing only two dots. Thus would be spoken as "Braille dots 4 and 5". The word "and" is not always used when listing many dots however.
Chart
Braille was added to the UnicodeUnicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
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:
Font differences
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 verses dots 3 and 5.The current Unicode charts, and Mac OS X (as of 10.6), 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 use small squares instead of small circles to indicate dots.