When using double-byte fonts in Flex, you should embed the smallest possible set of characters. If you embed a font's entire character set, the size of your application's SWF file can be very large. You can define sets of Unicode character ranges in the flex-config.xml file and then reference the name of that range in your style's @font-face declaration.

Flex provides predefined character ranges for common double-byte languages such as Thai, Kanji, Hangul, and Hebrew in the flash-unicode-table.xml file. This file is not processed by Flex, but is included to provide you with ready definitions for various character ranges. For example, the following character range for Thai is listed in the flash-unicode-table.xml file:

<language-range>
    <lang>Thai</lang>
    <range>U+0E01-U+0E5B</range>
</language-range>

To use this language in your Flex application, copy the character range to the flex-config.xml file or pass it on the command line by using the fonts.languages.language-range option. Add the full definition as a child tag to the <languages> tag, as the following example shows:

<flex-config>
    <fonts>
        <languages>
            <language-range>
                <lang>thai</lang>
                <range>U+0E01-U+0E5B</range>
            </language-range>
        </languages>
    </fonts>
    ...
</flex-config>

You can change the value of the <lang> element to anything you want. When you embed the font by using CSS, you refer to the language by using this value in the unicodeRange property of the @font-face declaration, as the following example shows:

@font-face {
    fontFamily:"Thai_font";
    src: url("../assets/THAN.TTF"); /* Embed from file */
    advancedAntiAliasing: true;
    unicodeRange:"thai"
}