[ft-devel] About the Cmap format 12

[丁力]

I found that FreeType can not get the correct glyph index from the font “Simsun-extb” corroding the Unicode of the character.

In the TTF, the cmap table use the format 12, and I always get 0, from the function FT_Get_Char_Index(), I think it maybe a bug to deal with the cmap which is format 12.

We can see that the Unicode is no in the range seg 2(00020000 - 0002A6D6), so there must be some error in the function tt_cmap12_char_map_binary() in “src\sfnt\ttcmap.c”.

 

This is a segment of the cmap in the font:

Subtable  3.   Platform ID:   3

               Specific ID:   10

               'cmap' Offset: 0x00000142

             ->Format: 12 : Segmented coverage (32 bit)

              Length:         40

              Version: 0

              Seg   1 : startCharCode = 00000020, endCharCode = 0000007F, startGlyphCode = 2

              Seg   2 : startCharCode = 00020000, endCharCode = 0002A6D6, startGlyphCode = 98

 

              Which Means:

                 1. Char 00000020 -> Index 2

                    Char 00000021 -> Index 3

                    Char 00000022 -> Index 4

                            ……………………………………

                            ………………………………

 

Thanks.

Regards,

 

2007-09-24