Skip to content

Latest commit

 

History

History
156 lines (128 loc) · 9.08 KB

Nextion Font Format Specification ZI version 3.md

File metadata and controls

156 lines (128 loc) · 9.08 KB
Raw

Nextion Font Format Specification

This is a reverse engineered specification of the Nextion font format. Use at own risk.

General information

The Nextion Font Format is a proprietary font format used by the Nextion Editor HMI software. Nextion Editor has a built in "Font Generator"-tool which converts standard fonts into .zi files that is compatible with the Nextion HMI displays.

Information
Software Nextion Editor V0.53
File extension .zi
File format version ZI version 3
Example file Arial_40_ascii.zi

Code pages / character encoding reference

Code page / encoding Value Number of characters
ASCII 0x01 95
GB2312 0x02 8273
ISO-8859-1 0x03 224
ISO-8859-2 0x04 224
ISO-8859-3 0x05 224
ISO-8859-4 0x06 224
ISO-8859-5 0x07 224
ISO-8859-6 0x08 224
ISO-8859-7 0x09 224
BIG5 0x1001 14225
ISO-8859-8 0x0A 224
ISO-8859-9 0x0B 224
ISO-8859-13 0x0C 224
ISO-8859-15 0x0D 224
ISO-8859-11 0x0E 224
KS_C_5601-1987 0x0F 3855
WINDOWS-1255 0x11 224
WINDOWS-1256 0x12 224
WINDOWS-1257 0x13 224
WINDOWS-1258 0x14 224
WINDOWS-874 0x15 224
KOI8-R 0x16 224

File format structure

Fixed header

Length: 0x1C (28)

0x00000000: 04 FF 00 0A 01 00 14 28 00 00 20 7E 5F 00 00 00
0x00000010: 03 0E 0E 00 2A 25 00 00 00 00 00 00
Offset Length Data Type Value Description
0x00000000 4 04 FF 00 0A * byte[] File signature / magic numbers
0x00000004 2 01 00 uint16 1 Code page / character encoding (possible values listed in the reference table)
0x00000006 1 14 byte 20 Character width
0x00000007 1 28 byte 40 Character height
0x00000008 1 00 byte 0 Code page multibyte - first byte start
0x00000009 1 00 byte 0 Code page multibyte - first byte end
0x0000000A 1 20 byte 32, ' ' (ASCII) Code page start / multibyte second byte start
0x0000000B 1 7E byte 126, '~' (ASCII) Code page end / multibyte second byte end
0x0000000C 4 5F 00 00 00 uint32 95 Number of characters in file
0x00000010 1 03 byte 3 File Format Version
0x00000011 1 0E byte 14 Length of font name
0x00000012 1 0E byte 14 Also length of font name? Always the same value as 0x11
0x00000013 1 00 byte 0 Reserved
0x00000014 4 2A 25 00 00 uint32 9514 Total length of font name and character data
0x00000018 4 00 00 00 00 uint32 0 Reserved

* The file signature/magic bytes for a .zi file containing the BIG5 code page is different from all other files. For BIG5 the magic bytes are 04 7E 22 0A. Which means that the second and third byte might be variable and have some meaning beyond being magic numbers.

Font name

Variable length font name. In this case the font name is 0x0E (14) bytes long as seen in offset 0x00000011.

0x00000010: 03 0E 0E 00 2A 25 00 00 00 00 00 00 41 72 69 61
0x00000020: 6C 5F 34 30 5F 61 73 63 69 69 00 00 00 00 00 00
Offset Length Data Type Value Description
0x0000001C 14 41 72 69 61 6C 5F 34 30 5F 61 73 63 69 69 string Arial_40_ascii Font name

Character data

The rest of the file contains the actual character data. The length of each character is calculated like this: character width * character height / 8. In our example we get; 20 * 40 / 8 which gives us 100 bytes per character. Characters are monochrome, which means that each bit in the 100 bytes gives us one pixel. 20 * 40 = 800 pixels.

Example data for one character. This is the exclamation mark character (!), which is the second character in the file. I skipped the first one, beacuse that is the space character which is blank.

0x00000080:                                           00 00
0x00000090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000000a0: 00 00 00 00 01 E0 00 1E 00 01 E0 00 1E 00 01 E0
0x000000b0: 00 1E 00 00 E0 00 0E 00 00 E0 00 0E 00 00 E0 00
0x000000c0: 0E 00 00 E0 00 0E 00 00 E0 00 0E 00 00 00 00 00
0x000000d0: 00 01 E0 00 1E 00 01 E0 00 00 00 00 00 00 00 00
0x000000e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000000f0: 00 00

The rest of the file contains the remaining characters supported by the font.

Character data example for a 16 pixels tall exclamation mark (!) character

This example shows how to read the pixel data for a character. The height of character is 16 pixels, which means it is 8 pixels wide. This gives us a total of 128 pixels. This also means that each of the 16 bytes contains the data for one line of pixels.

0x00000030:                               00 00 00 00 60 60
0x00000040: 60 60 60 60 00 60 00 00 00 00

Let's look at the bits of each byte:

00: 0 0 0 0 0 0 0 0
00: 0 0 0 0 0 0 0 0
00: 0 0 0 0 0 0 0 0
00: 0 0 0 0 0 0 0 0
60: 0 1 1 0 0 0 0 0
60: 0 1 1 0 0 0 0 0
60: 0 1 1 0 0 0 0 0
60: 0 1 1 0 0 0 0 0
60: 0 1 1 0 0 0 0 0
60: 0 1 1 0 0 0 0 0
00: 0 0 0 0 0 0 0 0
60: 0 1 1 0 0 0 0 0
00: 0 0 0 0 0 0 0 0
00: 0 0 0 0 0 0 0 0
00: 0 0 0 0 0 0 0 0
00: 0 0 0 0 0 0 0 0

Now let's remove the zeroes (blank pixel) and replace the ones with an X:

00: 
00: 
00: 
00: 
60:   X X          
60:   X X          
60:   X X          
60:   X X          
60:   X X          
60:   X X          
00: 
60:   X X          
00: 
00: 
00: 
00:

❗️ There's our exclamation mark ❗️