I need help installing pypng in Python 3.3

[Andrew Robinson]

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 don't know if this will help, but:

There is a package called image magic; which can convert any image to
any other type of image.
If that would not be a burden to install (most OS's have pre-compiled
working binaries) -- you could easily write a portable bitmap file to
disk using python (even without a library) -- and then convert it to png.

I have a little script I wrote in python to create a canvas, and allow
you to draw on it using very simple line drawing primitives, and then
save it to PBM. It's simple enough (only draws lines with different
pens) that you could examine it and write your own script to do the same
or better.

If this interests you, I will see if I can post the py script; or email
it to you.

--Andrew.

 

[icgwh]

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 couldfix myself. First I attempted to install pip but I couldn't get Windows torecognize 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 warningdisappear 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 ValueErroras 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 Ididn'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!

 

[icgwh]

I probably should have mentioned that I'm under W7 ultimate x64, I'm using eclipse Juno (latest) and pydev 2.7.1

 

[icgwh]

That's very kind of you but I don't think it would be particularly fitted to my needs. The program I'm trying to code creates an image as an 2D array of "pixels" which is defined by RGBA value. My program needs to access and modifies every component of every pixels in the image following a set of rules, kind of like the game of life, only more complex.

In fact I only need a library to "push" this array of pixels in a displayable format for the GUI and in PNG format to write the image to disk. I don'tneed to do any fancy stuff with the image, just being able to display and write it.

 

[icgwh]

That's very kind of you but I don't think it would be particularly fitted to my needs. The program I'm trying to code creates an image as an 2D array of "pixels" which is defined by RGBA value. My program needs to access and modifies every component of every pixels in the image following a set of rules, kind of like the game of life, only more complex.

In fact I only need a library to "push" this array of pixels in a displayable format for the GUI and in PNG format to write the image to disk. I don'tneed to do any fancy stuff with the image, just being able to display and write it.

 

[Andrew Robinson]

That's very kind of you but I don't think it would be particularly fitted to my needs. The program I'm trying to code creates an image as an 2D array of "pixels" which is defined by RGBA value. My program needs to access and modifies every component of every pixels in the image following a set of rules, kind of like the game of life, only more complex.

In fact I only need a library to "push" this array of pixels in a displayable format for the GUI and in PNG format to write the image to disk. I don't need to do any fancy stuff with the image, just being able to display and write it.

Then, actually, what I am suggesting was *almost* perfect.
To do transparency, you need to write the portable any map (PAM) formation.

Simply print a text header to a file which says:

P7
WIDTH 10
HEIGHT 10
DEPTH 4
MAXVAL 255
TUPLTYPE RGB_ALPHA
ENDHDR

And then dump your 2D array to that same file.
A very quick example in 17 lines of code:

io = open( "anyname.pam","w")
x,y = 10,10
gray=(128,128,128,255) # R,G,B,A value
picture = [ [ gray ] * x ] * y # Make a blank gray canvas 2D array

# Do whatever you want to the 2D picture array here!

io.write( "P7\nWIDTH %d\nHEIGHT %d\nDEPTH 4\nMAXVAL 255\nTUPLTYPE
RGB_ALPHA\nENDHDR\n" % (x,y) )

for yi in xrange( y ):
for xi in xrange( x ):
pixel = picture[yi][xi]
io.write( chr(pixel[0]) ) # R value
io.write( chr(pixel[1]) ) # G value
io.write( chr(pixel[2]) ) # B value
io.write( chr(pixel[3]) ) # A value
io.flush()

io.close()

And that's it. You may of course make this more efficient -- I'm just
showing it this way for clarity.
Many programs can read PAM directly; but for those that can't you can
use nettools, or imagemagick, to convert it to PNG.

 

[icgwh]

Do you have the file c:\Python33\Lib\site-packages\pypng-0.0.13-py3.3.egg ?

If not, you have not successfully installed pypng. Please try one of

the methods I gave above.

Yes I do have the egg.

I'm gonna try to summarize:

I don't have installations problems anymore but it seems that png.py is not run through 2to3 although it should since the setup.py is properly configured:

if sys.version_info >= (3,):
conf['use_2to3'] = True

I even tried to skip the if to ensure the second line is executed but nothing changed.

I don't know what I'm doing wrong but it seems that png.py is not properly translated to Python 3.

 

[icgwh]

Do you have the file c:\Python33\Lib\site-packages\pypng-0.0.13-py3.3.egg ?

If not, you have not successfully installed pypng. Please try one of

the methods I gave above.

Yes I do have the egg.

I'm gonna try to summarize:

I don't have installations problems anymore but it seems that png.py is not run through 2to3 although it should since the setup.py is properly configured:

if sys.version_info >= (3,):
conf['use_2to3'] = True

I even tried to skip the if to ensure the second line is executed but nothing changed.

I don't know what I'm doing wrong but it seems that png.py is not properly translated to Python 3.

 

[icgwh]

That's very kind of you but I don't think it would be particularly fitted to my needs. The program I'm trying to code creates an image as an 2D array of "pixels" which is defined by RGBA value. My program needs to access and modifies every component of every pixels in the image following a set of rules, kind of like the game of life, only more complex.

In fact I only need a library to "push" this array of pixels in a displayable format for the GUI and in PNG format to write the image to disk. I don't need to do any fancy stuff with the image, just being able to display and write it.

Then, actually, what I am suggesting was *almost* perfect.

To do transparency, you need to write the portable any map (PAM) formation.



Simply print a text header to a file which says:



P7

WIDTH 10

HEIGHT 10

DEPTH 4

MAXVAL 255

TUPLTYPE RGB_ALPHA

ENDHDR



And then dump your 2D array to that same file.

A very quick example in 17 lines of code:



io = open( "anyname.pam","w")

x,y = 10,10

gray=(128,128,128,255) # R,G,B,A value

picture = [ [ gray ] * x ] * y # Make a blank gray canvas 2D array



# Do whatever you want to the 2D picture array here!



io.write( "P7\nWIDTH %d\nHEIGHT %d\nDEPTH 4\nMAXVAL 255\nTUPLTYPE

RGB_ALPHA\nENDHDR\n" % (x,y) )



for yi in xrange( y ):

for xi in xrange( x ):

pixel = picture[yi][xi]

io.write( chr(pixel[0]) ) # R value

io.write( chr(pixel[1]) ) # G value

io.write( chr(pixel[2]) ) # B value

io.write( chr(pixel[3]) ) # A value

io.flush()



io.close()



And that's it. You may of course make this more efficient -- I'm just

showing it this way for clarity.

Many programs can read PAM directly; but for those that can't you can

use nettools, or imagemagick, to convert it to PNG.

That's really interesting! Thank you so much! Never heard of PAM before... I will try that!

 

[icgwh]

That's very kind of you but I don't think it would be particularly fitted to my needs. The program I'm trying to code creates an image as an 2D array of "pixels" which is defined by RGBA value. My program needs to access and modifies every component of every pixels in the image following a set of rules, kind of like the game of life, only more complex.

In fact I only need a library to "push" this array of pixels in a displayable format for the GUI and in PNG format to write the image to disk. I don't need to do any fancy stuff with the image, just being able to display and write it.

Then, actually, what I am suggesting was *almost* perfect.

To do transparency, you need to write the portable any map (PAM) formation.



Simply print a text header to a file which says:



P7

WIDTH 10

HEIGHT 10

DEPTH 4

MAXVAL 255

TUPLTYPE RGB_ALPHA

ENDHDR



And then dump your 2D array to that same file.

A very quick example in 17 lines of code:



io = open( "anyname.pam","w")

x,y = 10,10

gray=(128,128,128,255) # R,G,B,A value

picture = [ [ gray ] * x ] * y # Make a blank gray canvas 2D array



# Do whatever you want to the 2D picture array here!



io.write( "P7\nWIDTH %d\nHEIGHT %d\nDEPTH 4\nMAXVAL 255\nTUPLTYPE

RGB_ALPHA\nENDHDR\n" % (x,y) )



for yi in xrange( y ):

for xi in xrange( x ):

pixel = picture[yi][xi]

io.write( chr(pixel[0]) ) # R value

io.write( chr(pixel[1]) ) # G value

io.write( chr(pixel[2]) ) # B value

io.write( chr(pixel[3]) ) # A value

io.flush()



io.close()



And that's it. You may of course make this more efficient -- I'm just

showing it this way for clarity.

Many programs can read PAM directly; but for those that can't you can

use nettools, or imagemagick, to convert it to PNG.

That's really interesting! Thank you so much! Never heard of PAM before... I will try that!