PIXB File format

Basic structure

struct PIXBFile:
    struct Header:
        char[4]  = "PIXB"
        uint16_t: unknown
        uint16_t: Canvas size
        char[24]: unknown

    char[928]: data

Each pixels is stored in a 7 bit packed format which allow to store 8 pixel in 7 bytes:

bit 56-50	bit 49-43	bit 42-36	bit 35-29	bit 28-22	bit 21-15	bit 14-8	bit 7-0
pixel 7	pixel 6	pixel 5	pixel 4	pixel 3	piexl 2	pixel 1	pixel 0

Only value between 0 and 99 are valid, the palette only have 100 entry, all value equal or higher to 100 are considered to be color 0

Also, the file is always the same size and always contain enough space to store the 32x32 size.

If the image is using a 16x16 canvas or 24x24 canvas, the start of the image is shifted by a couple of pixels

Canvas size can take only 3 values:

0: 16x16 canvas
1: 24x24 canvas
2: 32x32 canvas

The unknown part do store information, but it is unknown as the main application hasn't been reversed yet. The iOS/Android app does not seems to use any of it, not the official windows conversion app.

Example unpacking code

import struct

[...]

def unpack7to8(data):
    ret = []
    val = struct.unpack("<Q", data + b"\0")[0]
    for i in range(8):
        ret.append(val & 0x7F)
        val = val >> 7
    return ret

This function take a binary string and return an array with pixel value in order left to right.

You can find in pixb2img.py a fully functional example application reading a PIXB file and converting it into an image format of your choice.

Color palette

The palette here is described in hexadecimal as in 0xRRGGBB. Depending on the tool you are using you make need to swap the red and blue components.

0xFFFFFF, 0xE9BFA8, 0xECC7AC, 0xEFCFB0, 0xF4DDB7, 0xF7E4BB, 0xF7E4BB, 0xFAEBBE, 0xFDF2C1, 0xFFF9C4, 
0xF2F2C3, 0xE3EBC5, 0xD4E3C0, 0xC5DBBE, 0xC5DDCC, 0xC4DEDA, 0xC4E0E8, 0xC4E1F5, 0xC8D9EE, 0xCBD0E6,
0xCEC5DE, 0xD0BAD5, 0xD6BBCB, 0xDDBDC0, 0xE3BEB4, 0xD1D1D2, 0xD37859, 0xD88A5F, 0xDE9B64, 0xE3AB69,
0xE9BA6E, 0xEFC972, 0xF4D777, 0xFAE57A, 0xFFF387, 0xE4E47E, 0xC6D57D, 0xA5C57C, 0x82B47B, 0x81B798,
0x7FBAB5, 0x7DBDD0, 0x7BBFE9, 0x8AB4DD, 0x96A3CE, 0x9F8EBB, 0xA572A6, 0xB17495, 0xBD7683, 0xC8776F,
0x7D7E7F, 0xC1001F, 0xC63F1F, 0xCC5E1E, 0xD4791D, 0xDC931A, 0xE5AB14, 0xEEC200, 0xF6D800, 0xFFEC00,
0xD4D51D, 0xA2BD30, 0x6BA53A, 0x118F40, 0x009266, 0x00958E, 0x0099B7, 0x009CDD, 0x348ECB, 0x5A76B2,
0x6F5496, 0x7E177A, 0x901366, 0xA20E50, 0xB20039, 0x1F1E21, 0x551415, 0x5F2517, 0x693618, 0x754819,
0x825B1A, 0x8F701A, 0x9E8519, 0xAD9B16, 0xBAAC12, 0x98981F, 0x6F8127, 0x456C2B, 0x005A2C, 0x006145,
0x006864, 0x007086, 0x0077A4, 0x266992, 0x3F537A, 0x4A3762, 0x500D4D, 0x560C3E, 0x58102E, 0x591320

2.9 KiB Raw Blame History

PIXB File format

Basic structure

Example unpacking code

Color palette

2.9 KiB

Raw Blame History