Support counting Asian characters double for line-breaking purposes

[remkop]

See argparse4j

enable if { "ja", "zh", "ko" }.contains(Locale.getDefault().getLanguage())

Apply to Unicode characters having East Asian Width property Wide/Full/Ambiguous.

[remkop]

http://unicode.org/reports/tr11/
https://ja.wikipedia.org/wiki/%E6%9D%B1%E3%82%A2%E3%82%B8%E3%82%A2%E3%81%AE%E6%96%87%E5%AD%97%E5%B9%85
http://www.unicode.org/Public/UCD/latest/ucd/EastAsianWidth.txt

[remkop]

From lanterna TerminalTextUtils:

    /**
     * Given a character, is this character considered to be a CJK character?
     * Shamelessly stolen from
     * <a href="http://stackoverflow.com/questions/1499804/how-can-i-detect-japanese-text-in-a-java-string">StackOverflow</a>
     * where it was contributed by user Rakesh N
     * @param c Character to test
     * @return {@code true} if the character is a CJK character
     *
     */
    public static boolean isCharCJK(final char c) {
        Character.UnicodeBlock unicodeBlock = Character.UnicodeBlock.of(c);
        return (unicodeBlock == Character.UnicodeBlock.HIRAGANA)
                || (unicodeBlock == Character.UnicodeBlock.KATAKANA)
                || (unicodeBlock == Character.UnicodeBlock.KATAKANA_PHONETIC_EXTENSIONS)
                || (unicodeBlock == Character.UnicodeBlock.HANGUL_COMPATIBILITY_JAMO)
                || (unicodeBlock == Character.UnicodeBlock.HANGUL_JAMO)
                || (unicodeBlock == Character.UnicodeBlock.HANGUL_SYLLABLES)
                || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS)
                || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A)
                || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B)
                || (unicodeBlock == Character.UnicodeBlock.CJK_COMPATIBILITY_FORMS)
                || (unicodeBlock == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS)
                || (unicodeBlock == Character.UnicodeBlock.CJK_RADICALS_SUPPLEMENT)
                || (unicodeBlock == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION)
                || (unicodeBlock == Character.UnicodeBlock.ENCLOSED_CJK_LETTERS_AND_MONTHS)
                || (unicodeBlock == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS && c < 0xFF61);    //The magic number here is the separating index between full-width and half-width
    }

    /**
     * Checks if a character is expected to be taking up two columns if printed to a terminal. This will generally be
     * {@code true} for CJK (Chinese, Japanese and Korean) characters.
     * @param c Character to test if it's double-width when printed to a terminal
     * @return {@code true} if this character is expected to be taking up two columns when printed to the terminal,
     * otherwise {@code false}
     */
    public static boolean isCharDoubleWidth(final char c) {
        return isCharCJK(c);
    }

[remkop]

Should add a setting to switch this off.

• doubleCountCJKCharacters
• detectWideCJKCharacters
• adjustLineBreaksForWideCJKCharacters