Reading a 24-bit icon in an mbm file

korakot (Korakot Chaovavanich) — Tue, 14 Feb 2006 12:27:42 GMT

Here's an example how I read the icon and display it on canvas
It's a continued part of my previous mbm hack.



>>> from appuifw import *

>>> from struct import unpack

>>> def readL(f, pos=None):     # helping function

...     if pos is not None:

...         f.seek(pos)

...     return unpack('L', f.read(4))[0]

...

>>> fxmbm = 'E:\\system\\apps\\FExplorer\\FExplorer.mbm'

>>> f = open(fxmbm, 'rb')

>>> trailer = readL(f, 16)

>>> num = readL(f, trailer)   # 19 icons

>>> offset = []

>>> for i in range(num):

...   offset.append(readL(f))

...

>>> offset

[20L, 68L, 116L, 474L, 588L, 1038L, 1228L, 1636L, 1864L, 2277L, 2430L, 3735L, 41

69L, 4569L, 4697L, 5197L, 5370L, 5897L, 6062L]

>>> start = offset[2]  # folder icon

>>> f.seek(start)

>>> length = readL(f) - readL(f)    # length of data section

>>> width, height = readL(f), readL(f)  # 16 x 13

>>> f.seek(start+0x28)  # start of data section

>>> data_enc = f.read(length)   # got the data

>>> def rle24_decode(bytes):

...     out = []

...     i = 0

...     while i < len(bytes):

...         n = ord(bytes[i])

...         i += 1

...         if n < 0x80:

...             out.append( bytes[i:i+3] * (n+1) )

...             i += 3

...         else:

...             n = 0x100 - n

...             out.append( bytes[i:i+3*n] )

...             i += 3*n

...     return ''.join(out)

...

>>> data = rel24_decode(data_enc)

>>> app.body = canvas = Canvas()

>>> for j in range(height):

...     for i in range(width):

...         p = 3*(j*width+i)

...         color = [ord(data[p+k]) for k in (2,1,0)]  # It's BGR

...         canvas.point((i,j), tuple(color))

...

>>>  # folder icon is drawn on screen

DZone Snippets: rle code

Reading a 24-bit icon in an mbm file