Archived:How to draw an icon on canvas in PySymbian

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Created: cyke64 (15 Mar 2007)

Last edited: hamishwillee (08 May 2013)

Python have 2 different classes for graphics data :

• Icon class represents icon (typically from .mbm file) which can be put in ListBox for selection.
• Image class represents a bigger image which can be drawn upon.

These 2 classes can't convert to/from each other.

But you can use a library that read .mbm file and draw an Image from the data there. So, you can make an icon into an image the module icon_image whose source code is below can be used for this purpose.

#
# module icon_image from Korakot user
#
# called by just import icon_image
# im = icon_image(file_mbm, idx)
 
from graphics import Image
from struct import unpack
 
def readL(f, pos=None):
    if pos is not None:
        f.seek(pos)
    return unpack('L', f.read(4))[0]
 
def open(file_mbm='z:\\system\\data\\avkon.mbm', idx = 28):
 
    # read icon data from mbm file
    f = file(file_mbm, 'rb')
    if readL(f) != 0x10000041:
        return None  # work for mbm on ROM (z:) only
    start = readL(f, 8+4*idx)
    f.seek(start+20)
    length = readL(f) - readL(f)  # pd_size - offset
    width, height = readL(f), readL(f)
    enc = readL(f, start+56)
    f.seek(start+68)
    data_encoded = f.read(length)
 
    # decode the data
    data_padded = rle_decode(data_encoded, enc)
    mat = bit_matrix(data_padded, width, height)
 
    im = Image.new((width, height), '1')
    for j in range(height):
        for i in range(width):
            im.point((i,j), mat[j][i]*0xffffff)
    return im
 
# Decode of 8-bit RLE
# Either to repeat-(n+1)-times or not repeat (100-n) bytes
def rle_decode(bytes, enc=1):
    if not enc: return bytes
    out = []
    i = 0
    while i < len(bytes):
        n = ord(bytes[i])
        i += 1
        if n < 0x80:
            out.append( bytes[i] * (n+1) )
            i += 1
        else:
            n = 0x100 - n
            out.append( bytes[i:i+n] )
            i += n
    return ''.join(out)
 
# from bytes to bit matrix
# Each line was padded to 4-byte boundary, must discard the end
def bit_matrix(bytes, width, height):
    mat = []
    k = 0
    for j in range(height):
        line = []
        while len(line)<width:
            longint, = unpack('L', bytes[k: k+4])
            k += 4
            toget = min(width - len(line), 32)
            for i in range(toget):
                longint, r = divmod(longint, 2)
                line.append(int(r))
        mat.append(line)
    return mat

Here's an example using this module.

• Python 2nd Edition

from appuifw import *
import icon_image, e32
 
app.body = c = Canvas()
# choose a bitmap from plenty inside mbm (multi-bitmap)
icon = icon_image('z:\\system\\data\\avkon.mbm', 28) 
c.blit(icon)
 
e32.ao_sleep(10)  # 10 sec to end program

• Python 3rd Edition

from appuifw import *
import icon_image, e32
 
app.body = c = Canvas()
# choose a bitmap from plenty inside mbm (multi-bitmap)
icon = icon_image('z:\\system\\data\\avkon2.mbm', 28) 
c.blit(icon)
 
e32.ao_sleep(10)  # 10 sec to end program

Limitations : only 1-bit icons.