Programmatically determine number of strokes in a Chinese character? - unicode

Does Unicode store stroke count information about Chinese, Japanese, or other stroke-based characters?

A little googling came up with Unihan.zip, a file published by the Unicode Consortium which contains several text files including Unihan_RadicalStrokeCounts.txt which may be what you want. There is also an online Unihan Database Lookup based on this data.

In Python there is a library for that:
>>> from cjklib.characterlookup import CharacterLookup
>>> cjk = CharacterLookup('C')
>>> cjk.getStrokeCount(u'日')
4
Disclaimer: I wrote it

You mean, is it encoded somehow in the actual code point? No. There may well be a table somewhere you can find on the net (or create one) but it's not part of the Unicode mandate to store this sort of metadata.

If you want to do character recognition goggle HanziDict.
Also take a look at the Unihan data site:
http://www.unicode.org/charts/unihanrsindex.html
You can look up stroke count and then get character info. You might be able to build your own look up.

UILocalizedIndexedCollation can be a total solution.
https://developer.apple.com/library/ios/documentation/iPhone/Reference/UILocalizedIndexedCollation_Class/UILocalizedIndexedCollation.html

Related

Where to get a reference image for any unicode code point?

I am looking for an online service (or collection of images) that can return an image for any unicode code point.
Unicode.org does not have an image for each one, consider for example
http://www.unicode.org/cgi-bin/GetUnihanData.pl?codepoint=31cf
EDIT: I need to use these images programmatically, so the code chart PDFs provided at unicode.org are not useful.
The images in the PDF are copyrighted, so there are legal issues around extracting them. (I am not a lawyer.) I suspect that those legal issues prevent a simple solution from being provided, unless someone wants to go to the trouble of drawing all of those images. It might happen, but seems unlikely.
Your best bet is to download a selection of fonts that collectively cover the entire range of characters, and display the characters using those fonts. There are two difficulties with this approach: combining characters and invisible characters.
The combining characters can easily be detected from the Unicode database, and you can supply a base character (such as NBSP) to use for displaying them. (There is a special code point intended for this purpose, but I can't find it at the moment.)
Invisible characters could be displayed with a dotted square box containing the abbreviation for the character. Those you may have to locate manually and construct the necessary abbreviations. I am not aware of any shortcuts for that.

Simplified Chinese Unicode table

Where can I find a Unicode table showing only the simplified Chinese characters?
I have searched everywhere but cannot find anything.
UPDATE :
I have found that there is another encoding called GB 2312 -
http://en.wikipedia.org/wiki/GB_2312
- which contains only simplified characters.
Surely I can use this to get what I need?
I have also found this file which maps GB2312 to Unicode -
http://cpansearch.perl.org/src/GUS/Unicode-UTF8simple-1.06/gb2312.txt
- but I'm not sure if it's accurate or not.
If that table isn't correct maybe someone could point me to one that is, or maybe just a table of the GB2312 characters and some way to convert them?
UPDATE 2 :
This site also provides a GB/Unicode table and even a Java program to generate a file
with all the GB characters as well as the Unicode equivalents :
http://www.herongyang.com/gb2312/
The Unihan database contains this information in the file Unihan_Variants.txt. For example, a pair of traditional/simplified characters are:
U+673A kTraditionalVariant U+6A5F
U+6A5F kSimplifiedVariant U+673A
In the above case, U+6A5F is 機, the traditional form of 机 (U+673A).
Another approach is to use the CC-CEDICT project, which publishes a dictionary of Chinese characters and compounds (both traditional and simplified). Each entry looks something like:
宕機 宕机 [dang4 ji1] /to crash (of a computer)/Taiwanese term for 當機|当机[dang4 ji1]/
The first column is traditional characters, and the second column is simplified.
To get all the simplified characters, read this text file and make a list of every character that appears in the second column. Note that some characters may not appear by themselves (only in compounds), so it is not sufficient to look at single-character entries.
The OP doesn't indicate which language they're using, but if you're using Ruby, I've written a small library that can distinguish between simplified and traditional Chinese (plus Korean and Japanese as a bonus). As suggested in Greg's answer, it relies on a distilled version of Unihan_Variants.txt to figure out which chars are exclusively simplified and which are exclusively traditional.
https://github.com/jpatokal/script_detector
Sample:
p string
=> "我的氣墊船充滿了鱔魚."
> string.chinese?
=> true
> string.traditional_chinese?
=> true
> string.simplified_chinese?
=> false
But as the Unicode FAQ duly warns, this requires sizable fragments of text to work reliably, and will give misleading results for short strings. Consider the Japanese for Tokyo:
p string
=> "東京"
> string.chinese?
=> true
> string.traditional_chinese?
=> true
> string.japanese?
=> false
Since both characters happen to also be valid traditional Chinese, and there are no exclusively Japanese characters, it's not recognized correctly.
I'm not sure if that's easily done. The Han ideographs are unified in Unicode, so it's not immediately obvious how to do it. But the Unihan database (http://www.unicode.org/charts/unihan.html) might have the data you need.
Here is a regex of all simplified Chinese characters I made. For some reason Stackoverflow is complaining, so it's linked in a pastebin below.
https://pastebin.com/xw4p7RVJ
You'll notice that this list features ranges rather than each individual character, but also that these are utf-8 characters, not escaped representations. It's served me well in one iteration or another since around 2010. Hopefully everyone else can make some use of it now.
If you don't want the simplified chars (I can't imagine why, it's not come up once in 9 years), iterate over all the chars from ['一-龥'] and try to build a new list. Or run two regex's, one to check it is Chinese, but is not simplified Chinese
According to wikipedia simplified Chinese v. traditional, kanji, or other formats is left up to the font rendering in many cases. So while you could have a selection of simplified Chinese codepoints, this list would not be at all complete since many characters are no longer distinct.
I don't believe that there's a table with only simplified code points. I think they're all lumped together in the CJK range of 0x4E00 through 0x9FFF

A set of typefaces that cover the whole Unicode character range

Does anybody know a set of typefaces that altogether cover the whole Unicode character range? we know that it is impossible to display all unicode characters using just one or two fonts. But probably, we can find a set of fonts using them the whole Unicode range could be displayed. Does anybody have any experience?
Thank you so much in advance.
One way to find such set of fonts is to look into Windows Font Linking. If you take a look at the registry key HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\FontLink\SystemLink you'll see fonts that "link" to cover the complete Unicode set.
as far as i know Arial Unicode is one of the full.
Everson Mono covers a large portion of the Unicode characters, and SIL International makes a lot of different fonts for minority languages.

Detect presence of a specific charset

I need a way to detect whether a file contains characters from a certain charset.
Specifically, I want to detect the presence of UTF8-encoded cyrillic characters in a series of files. Is there a tool to do this?
Thanks
If you are looking for ready solution, you might want to try Enca.
However, if you only want to detect presence of what can be possibly decoded as UTF-8 Cyrillic characters (without any complete UTF-8 validity checks), you just have to grep for something like /(\xD0[\x81\x90-\xBF]|\xD1[\x80-\x8F\x91]){n,}/ (this exact regexp is for n subsequent UTF8-encoded Russian Cyrillic characters). For additional check that the whole file contains only valid UTF-8 data you can use something like isutf8(1).
Both methods have their good and bad sides and may sometimes give wrong results.
IIRC the ICU library has code that does character set detection. Though it's basically a best effort guess.
Edit: I did remember correctly, check out this paper / tutorial

How can I figure out what code page I am looking at?

I have a device with some documentation on how to send it text. It uses 0x00-0x7F to send 'special' characters like accented characters, euro signs, ...
I am guessing they copied an existing code page and made some changes, but I have no idea how to figure out what code page is closest to the one in my documentation.
In theory, this should be easy to do. For example, they map Á to 0x41, so if I could find some way to go through all code pages and find the ones that have this character on that position, it would be a piece of cake.
However, all I can find on the internet are links to code page dumps just like the one I'm looking at, or software that uses heuristics to read text and guess the most likely code page. Surely someone out there has made it possible to look up what code page one is looking at ?
If it uses 0x00 to 0x7F for the "special" characters, how does it encode the regular ASCII characters?
In most of the charsets that support the character Á, its codepoint is 193 (0xC1). If you subtract 128 from that, you get 65 (0x41). Maybe your "codepage" is just the upper half of one of the standard charsets like ISO-8859-1 or windows-1252, with the high-order bit set to zero instead of one (that is, subtracting 128 from each one).
If that's the case, I would expect to find a flag you can set to tell it whether the next bunch of codepoints should be converted using the "upper" or "lower" encoding. I don't know of any system that uses that scheme, but it's the most sensible explanation I can come with for the situation you describe.
There is no way to auto-detect the codepage without additional information. Below the display layer it’s just bytes and all bytes are created equal. There’s no way to say “I’m a 0x41 from this and that codepage”, there’s only “I’m 0x41. Display me!”
What endian is the system? Perhaps you're flipping bit orders?
In most codepages, 0x41 is just the normal "A", I don't think any standard codepages have "Á" in that position. It could have a control character somewhere before the A that added the accent, or uses a non-standard codepage.
I don't see any use in knowing the "closest codepage", you just need to use the docs you got with the device.
Your last sentence is puzzling, what do you mean by "possible to look up what code page one is looking at"?
If you include your whole codepage, people here on SO could be more helpful and give you more insight about this issue, having one data point 0x41=Á doesn't help much.
Somewhat random idea, but if you can get replicate a significant amount of the text off the device, you could try running it through something like the detect function in http://chardet.feedparser.org/.