CTR Font Format
.bcfnt files are bitmap fonts made for the 3ds. The system font uses this format too except the header is changed from CFNT to CFNU and all file offsets are changed to absolute in memory offsets.
| Offset
|
Size
|
Description
|
| 0x00
|
0x04
|
Magic Header (either CFNT or CFNU)
|
| 0x04
|
0x02
|
Endianness (0xFEFF = little, 0xFFFE = big)
|
| 0x06
|
0x02
|
Header Size
|
| 0x08
|
0x04
|
Version (observed to be 0x03000000)
|
| 0x0C
|
0x04
|
File size (the total)
|
| 0x10
|
0x04
|
Number of "blocks" to read
|
| Offset
|
Size
|
Description
|
| 0x00
|
0x04
|
Magic Header (FINF)
|
| 0x04
|
0x04
|
Section Size
|
| 0x08
|
0x01
|
Font Type
|
| 0x09
|
0x01
|
Line Feed
|
| 0x0A
|
0x02
|
Alter Char Index
|
| 0x0C
|
0x03
|
Default Width (3 bytes: Left, Glyph Width, Char Width)
|
| 0x0F
|
0x01
|
Encoding
|
| 0x10
|
0x04
|
TGLP Offset
|
| 0x14
|
0x04
|
CWDH Offset
|
| 0x18
|
0x04
|
CMAP Offset
|
| 0x1C
|
0x01
|
Height
|
| 0x1D
|
0x01
|
Width
|
| 0x1E
|
0x01
|
Ascent
|
| 0x1F
|
0x01
|
Padding
|
| Offset
|
Size
|
Description
|
| 0x00
|
0x04
|
Magic Header (TGLP)
|
| 0x04
|
0x04
|
Section Size
|
| 0x08
|
0x01
|
Cell Width
|
| 0x09
|
0x01
|
Cell Height
|
| 0x0A
|
0x01
|
Baseline Position
|
| 0x0B
|
0x01
|
Max Character Width
|
| 0x0C
|
0x04
|
Sheet Size
|
| 0x10
|
0x02
|
Number of Sheets
|
| 0x12
|
0x02
|
Sheet Image Format 0-13: (RGBA8, RGB8, RGBA5551, RGB565, RGBA4, LA8, HILO8, L8, A8, LA4, L4, A4, ETC1, ETC1A4)
|
| 0x14
|
0x02
|
Number of Sheet rows
|
| 0x16
|
0x02
|
Number of Sheet lines
|
| 0x18
|
0x02
|
Sheet Width
|
| 0x1A
|
0x02
|
Sheet Height
|
| 0x1C
|
0x04
|
Sheet Data Offset
|
| Offset
|
Size
|
Description
|
| 0x00
|
0x04
|
Magic Header (FINF)
|
| 0x04
|
0x04
|
Section Size
|
| 0x08
|
0x01
|
Font Type
|
| 0x09
|
0x01
|
Line Feed
|
| 0x0A
|
0x02
|
Alter Char Index
|
| 0x0C
|
0x03
|
Default Width (3 bytes: Left, Glyph Width, Char Width)
|
| 0x0F
|
0x01
|
Encoding
|
| 0x10
|
0x04
|
TGLP Offset
|
| 0x14
|
0x04
|
CWDH Offset
|
| 0x18
|
0x04
|
CMAP Offset
|
| 0x1C
|
0x01
|
Height
|
| 0x1D
|
0x01
|
Width
|
| 0x1E
|
0x01
|
Ascent
|
| 0x1F
|
0x01
|
Padding
|
| Offset
|
Size
|
Description
|
| 0x00
|
0x04
|
Magic Header (CMAP)
|
| 0x04
|
0x04
|
Section Size
|
| 0x08
|
0x02
|
Code Begin
|
| 0x0A
|
0x02
|
Code End
|
| 0x0C
|
0x02
|
Mapping Method (0 = Direct, 1 = Table, 2 = Scan)
|
| 0x0E
|
0x02
|
Reserved?
|
| 0x10
|
0x04
|
Next CMAP Offset
|
Depending on the mapping method the next bytes are read like so:
Direct:
IndexOffset = read uint16
Table:
IndexTable = read uint16 array (CodeEnd - CodeBegin + 1)
Scan:
Number of Scan Entries = read uint16
for every scan entry: read uint16 & read uint16
| Offset
|
Size
|
Description
|
| 0x00
|
0x04
|
Magic Header (CWDH)
|
| 0x04
|
0x04
|
Section Size
|
| 0x08
|
0x02
|
Start Index
|
| 0x0A
|
0x02
|
End Index
|
| 0x0C
|
0x04
|
Next CWDH Offset
|
| 0x10
|
3 * (EndIndex - StartIndex + 1)
|
Char Widths (3 bytes: Left, Glyph Width, Char Width)
|