pngcompression.py
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00032 
00033 from PIL import Image
00034 from base64 import standard_b64encode, standard_b64decode
00035 from StringIO import StringIO
00036 from math import floor, ceil, sqrt
00037 
00038 
00039 def encode(string):
00040     """ PNG-compress the string in a square RBG image padded with '\n', return the b64 encoded bytes """
00041     length = len(string)
00042     width = floor(sqrt(length/3.0))
00043     height = ceil((length/3.0) / width)
00044     bytes_needed = int(width * height * 3)
00045     while length < bytes_needed:
00046         string += '\n'
00047         length += 1
00048     i = Image.fromstring('RGB', (int(width), int(height)), string)
00049     buff = StringIO()
00050     i.save(buff, "png")
00051     encoded = standard_b64encode(buff.getvalue())
00052     return encoded
00053 
00054 def decode(string):
00055     """ b64 decode the string, then PNG-decompress """
00056     decoded = standard_b64decode(string)
00057     buff = StringIO(decoded)
00058     i = Image.open(buff)
00059     return i.tostring()


rosbridge_library
Author(s): Jonathan Mace
autogenerated on Mon Oct 6 2014 06:58:09