I need help installing pypng in Python 3.3

icgwh at tagyourself.com icgwh at tagyourself.com
Mon Oct 29 08:23:27 EDT 2012


Hello all,

I am very new to python. I am currently porting a little project of mine from java to python and I need to be able to construct and write png images. I naturally turned myself toward pypng to accomplish this.

I learned from the net that pypng 0.0.13 is supposed to work in Python 3.x when run through '2to3'. However, in my case, it apparently does not. 

I ran into various problems when trying to install it, some of them I could fix myself. First I attempted to install pip but I couldn't get Windows to recognize pip as an internal command as the prompt informs me.
Then I tried to directly run "setup.py install" from the pypng folder. It didn't work as I got a syntax error. I noticed that in the beginning of the installation process, the following warning was displayed: "conf[use_2to3 = true] unrecognized configuration option"

At that point I was already pretty pissed but I managed to make the warning disappear by updating (installing?) distribute. After that there are no more errors during the installation process and everything seems to work fine. (This seems still strange to me as 2to3 was present in Tools/Script out of the box)


I use pydev in Eclipse and pydev reports several error in png.py anytime I want to import or use it. When trying to import from IDLE I get:

except ValueError, e:
                 ^
Syntax error, line 1863

that paricular error I was able to fix by changing it to "except ValueError as e:" but I don't understand why 2to3 didn't do it automatically.
There are several more errors reported by pydev, here are a few:

line 1368 : "raise ValueError('Chunk %s too short for checksum.', tag)"
            Undefined variable: tag

line 2736 : "rows = [map(numpy.uint16, range(0,0x10000,0x5555))]"
            Undefined variable from import: uint16


The second one made me suspect I needed to install numpy too. As there are no installers for numpy aimed toward Python3.3.

I decided to install Python2.7 and retry the whole process. Unfortunately I didn't get much more success. I get the exact same errors in pydev when using the 2.7 version of the interpreter and I cannot install numpy either because when I run the .exe file aimed toward Python 2.7 i get the error message:

"Python version 2.7 required, which was not found in the registry"

I then have the option to manually enter the path to Python 2.7 but the textform is greyed out and I can't type in anything.


At that point I decided to go look for help and Here I am...

I am truly grateful to anyone who takes the time to help me in this matter.
Thank you!



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