The font for this test case contains a ‘cmap’ table of format 0, platform 1, encoding 0, language 18. Platform 1 means the classic Macintosh up to MacOS 9; the combination of encoding 0 and language 18 indicates the MacOS Turkish character encoding. (The QuickDraw graphics system of the classic Macintosh had used code 17 for the Turkish language; as described by section ”The ‘cmap’ table and language codes” in the Apple TrueType specification, Macintosh language codes in the ‘cmap’ table are 1 higher than the QuickDraw language code). Although Apple has deprecated the Macintosh encodings in favor of Unicode in 2002, present-day renderers may still encounter such fonts. For example, users sometimes want to open electronic documents that were created a long time ago, and certain file formats contain embedded fonts.

A correct implementation should be able to render Turkish text with this test font, using Unicode’s conversion table. If you see boxes, missing characters, or glyphs from a different (fallback) font in the rendering below, it’s a sign that your implementation cannot handle legacy fonts that were built for MacOS.