Author: yifei / Created: June 8, 2017, 3:17 p.m. / Modified: June 8, 2017, 3:32 p.m. / Edit


from wikipedia

In the Unicode standard, a plane is a continuous group of 65536 code points. There are 17 planes, identified by the numbers 0 to 16, which corresponds with the possible values 00–10 hexadecimal of the first two positions in six position format (hhhhhh).

Plane 0 is the Basic Multilingual Plane (BMP), which contains most commonly-used characters. The higher planes 1 through 16 are called "supplementary planes", As of Unicode version 9.0, six of the planes have assigned code points (characters), and four are named.

The limit of 17 (which is not a power of 2) is due to the design of UTF-16, which can encode a maximum value of 0x10FFFF,[2] the last code point in plane 16. The encoding scheme used by UTF-8 was designed with a much larger limit of 231 code points (32,768 planes), and can encode 221 code points (32 planes) even if limited to 4 bytes. Since Unicode limits the code points to the 17 planes that can be encoded by UTF-16, code points above 0x10FFFF are invalid in UTF-8 and UTF-32.

The 17 planes can accommodate 1,114,112 code points. Of these, 2,048 are surrogates, 66 are non-characters, and 137,468 are reserved for private use, leaving 974,530 for public assignment.

Planes are further subdivided into Unicode blocks, which, unlike planes, do not have a fixed size. The 273 blocks defined in Unicode 9.0 cover 24% of the possible code point space, and range in size from a minimum of 16 code points (twelve blocks) to a maximum of 65,536 code points (Supplementary Private Use Area-A and -B, which constitute the entirety of planes 15 and 16). For future usage, ranges of characters have been tentatively mapped out for most known current and ancient writing systems.

Plane 0(BMP)

0000-007F   ASCII       
0080-1FFF   各种鸟语        
2000-206F   常用标点    General Punctuation 包含双引号
2070-209F   上下标     
20A0-20CF   货币符号        
20D0-214F   各种物理符号      
2150-218f   罗马数字        
2190-21ff   箭头 https://en.wikipedia.org/wiki/Arrows_(Unicode_block)  有emoji
2220-22FF   数学符号        
2300-23ff   符号  Miscellaneous Technical 有emoji
2400-245f   符号      
2460-24ff   圆圈  Enclosed Alphanumerics  
2500-257f   画方块字符   Box Drawing 好多人用做竖线
2580-259f   方块字符    Box Elements    
25A0-2e7f   各种奇怪的字符,包含部分表情 emoji
3000-303f   中文符号和标点,包含了中括号等,竟然有双字节宽的引号
3040-33ff   各种中文符号,3190也是竖线
4DC0-4DFF   八卦符号        
4e00-9fff   CJK统一表意文字       
A000-D7af   各种鸟语        
D7B0-D7FF   UTF-16高半区,实际使用D800-DBFF
DC00-DFFF   低半区     
E000-F8FF   私用区, 其中 F8FF 表示 
F900-FAFF   CJK统一表意文字       
FB00-FE0F   各种鸟语        
FE10-FE1F   竖排符号        
FE30-FE4F   CJK兼容标点     
FE50-FE6F   小标点     
FE70-FEFF   鸟语      
FF00-FFEF   全角与半角       
FFF0-FFFF   奇葩      

Plane 1 (SMP)


1F000-1FFFF 各种表情 emoji


text vs emoji style

Emoji 有text和emoji-style两种形式,每个emoji 有一个默认的形式,可以添加字符来强制指定形式:\ufe0e \ufe0f

skin colors


emoji combination

组合,Emoji 还可以组合成新的 emoji,这样来拟补不足,使用\u200d http://www.unicode.org/emoji/charts/emoji-zwj-sequences.html

更多 emoji 表情参见:http://www.unicode.org/Public/emoji/1.0/emoji-data.txt


Surrogate to Non-Surrogate:

N = 0x10000 + (H - 0xd800) * 0x400 + (L - 0xDC00)

Non-Surrogate to Surrogate

H = (N - 0x10000) / 0x400 + 0xD800 L = (N - 0x10000) % 0x400 + 0xdc00


narrow build python does not support SMP, python on mac are all narrow build.if you got narrow build, you will have to use to unicode char to represent.




Unicode character orders

Left-to-Right Mark/Right-to-Left Mark

not very useful, fix puncutation positions


Left-to-right Order/Right-to-Left Order

This is very powerful, override normal character directions

U+202d LEFT-TO-RIGHT OVERRIDE The following text will be left-to-right. Additionally, the directionality of characters is changed to left-to-right. Used alone in an English text, this will only affect characters that are right-to-left by default, like Arabic letters. U+202e RIGHT-TO-LEFT OVERRIDE The following text will be right-to-left. Additionally, the directionality of characters is changed to right-to-left. Use this character to completely screw up an English text.

see https://www.explainxkcd.com/wiki/index.php/1137:_RTL https://www.zhihu.com/question/43621727/answer/96178474

white spaces