From: "Iñaki Baz Castillo" <ibc@...>
Date: 2009-12-03T09:24:55+09:00
Subject: Re: Encoding/decoding a image as Base64 (fails under Ruby1.9 but works under Ruby1.8)

El Jueves, 3 de Diciembre de 2009, Iñaki Baz Castillo escribió:
> Hi, the folowing code encodes and decodes a image file as Base64:
> 
> - Encode "icon.png" in Base64 as "base64.txt":
> --------------------------------------
>   File.open("base64.txt","w") do |file|
>     file.write [open("icon.png").read].pack("m")
>   end
> --------------------------------------
> 
> - Decode "base64.txt" as a PNG "new_icon.png" file:
> --------------------------------------
>   File.open('new_icon.png', 'wb') do |file|
>     file << (IO.readlines('base64.txt').to_s.unpack('m')).first
>   end
> --------------------------------------
> 
> 
> It works perfectly under Ruby1.8 (after encoding and decoding "icon.png" is
> exatcly the same as "new_icon.png", the same binay file).
> 
> However running under Ruby1.9 the result is different since "new_icon.png"
>  is a corrupted image file. When I try to open it with a image viewer I get
>  this error (under Linux):
> 
>   libpng warning: gAMA: CRC error
>   libpng error: PNG unsigned integer out of range.
> 
> 
> Which is the difference when using Ruby1.9? how to solve it?
> Thanks a lot.

The difference is in the second step, the decoding process, since "base64.txt" 
file is the same using Ruby1.8 or 1.9.




-- 
Iñaki Baz Castillo <ibc@aliax.net>