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Saving image files from Music21

I've downloaded a bunch of .krn files, and I'd like to convert them into images - either pngs or jpgs - using music21. I've tried this:
When I do this:
from music21 import *
op = krnfile
s = converter.parse(op)
s.show()
I see a great image file in the Jupyter Notebook I'm using, but when I try to save that file programatically like this:
s.write(fp = 'outputfile.png', fmt = 'png')
It says:
Music21ObjectException: cannot support showing in this format yet: png
Which seems a little weird since it obviously manages to make an image for display in the notebook.
It looks like maybe I could use LilypondConverter.createPNG(fileName=None) from this, but is installing Lilypond required? I already have MuseScore2 installed, which opens when I call s.show().
Thanks a lot!
Alex

Install musescore on your computer, re-run python -m music21.configure to help it find it and then do:
from music21 import *
op = 'krnfile.krn'
s = converter.parse(op)
fp = s.write('musicxml.png')
# or just s.show('musicxml.png') to test that it works.
If it's a multi-page file, fp will be the path to the first page. It will end in -1 or -01 or -001 etc. You can read through the directory to find other files with the same name until there are no more to get all the images.

If you use n.show('lily.png'), it should create a temporary png file somewhere. Try to use it and an image may open.
Sorry i don't know much yet, I hope it helps.

Using MemoryFS file-like object with PIL Image

I'm trying to open Image file from PyFileSystem MemoryFS using PIL, I tried to do that like this example and i got the error below:
from PIL import Image
from fs.memoryfs import MemoryFS
fs=MemoryFS()
fs.makedir("test")
out=fs.open("test/file.jpg",'wb')
out.write(someimagefile.read())
out.close()
in=fs.open("test/file.jpg",'rb')
im=Image.open(in) #error: cannot identify image file <IO wrapper for <MemoryFile in <MemoryFS> test/file.jpg>>
however if I don't use a directory (ex. out=fs.open("file.jpg",'wb')) It does work as expected.
What am I doing wrong?
Thanks for your help.

I already get an error using the following line:
from fs.memoryfs import MemoryFS
Probably I don't have that library installed. Do you need this library? You can just open the image without opening it with MemoryFS:
im = Image.open("test/file.jpg")
Side note: I wouldn't use in as variable name, since it is also a Python keyword.

Wand Python multi-size icon

i'm trying to use Wand to create a multi-size ico, but i don't find anything talking about that, only normal conversion, to ico... i've found "Sequences":
https://wand.readthedocs.org/en/latest/roadmap.html
and sequences look like what i need, but i only see samples trying to read the multiple images, but not how to create, am i missing something? or is not possible?
or is it possible to do using PIL/PILLOW?

You can append() a single image to Image.sequence list. For example:
from wand.color import Color
from wand.image import Image
with Image(width=32, height=32, background=Color('red')) as ico:
with Image(width=16, height=16, background=Color('green')) as s16:
ico.sequence.append(s16)
ico.save(filename='multisized.ico')
Result (multisized.ico):

I had a similar problem, but with creating a multi-page PDF from multiple JPEG files. In Imagemagick i used command -adjoin. In Wand i did the following:
from glob import glob
from wand.image import Image
files = glob('*.jpg')
with Image() as orig: # create empty Image object
for f in files:
page = Image(filename=f)
orig.sequence.append(page)
orig.save(filename='result.pdf')

Converting .jpg images to .png

I've looked around and read the docs, and found no way or solution, so I ask here. Is there any packages available to use Python to convert a JPG image to a PNG image?

You could always use the Python Image Library (PIL) for this purpose. There might be other packages/libraries too, but I've used this before to convert between formats.
This works with Python 2.7 under Windows (Python Imaging Library 1.1.7 for Python 2.7), I'm using it with 2.7.1 and 2.7.2
from PIL import Image
im = Image.open('Foto.jpg')
im.save('Foto.png')
Note your original question didn't mention the version of Python or the OS you are using. That may make a difference of course :)

Python Image Library: http://www.pythonware.com/products/pil/
From: http://effbot.org/imagingbook/image.htm
import Image
im = Image.open("file.png")
im.save("file.jpg", "JPEG")
save
im.save(outfile, options...)
im.save(outfile, format, options...)
Saves the image under the given filename. If format is omitted, the
format is determined from the filename extension, if possible. This
method returns None.
Keyword options can be used to provide additional instructions to the
writer. If a writer doesn't recognise an option, it is silently
ignored. The available options are described later in this handbook.
You can use a file object instead of a filename. In this case, you
must always specify the format. The file object must implement the
seek, tell, and write methods, and be opened in binary mode.
If the save fails, for some reason, the method will raise an exception
(usually an IOError exception). If this happens, the method may have
created the file, and may have written data to it. It's up to your
application to remove incomplete files, if necessary.

As I searched for a quick converter of files in a single directory, I wanted to share this short snippet that converts any file in the current directory into .png or whatever target you specify.
from PIL import Image
from os import listdir
from os.path import splitext
target_directory = '.'
target = '.png'
for file in listdir(target_directory):
filename, extension = splitext(file)
try:
if extension not in ['.py', target]:
im = Image.open(filename + extension)
im.save(filename + target)
except OSError:
print('Cannot convert %s' % file)

from glob import glob
import cv2
pngs = glob('./*.png')
for j in pngs:
img = cv2.imread(j)
cv2.imwrite(j[:-3] + 'jpg', img)
this url: https://gist.github.com/qingswu/1a58c9d66dfc0a6aaac45528bbe01b82

import cv2
image =cv2.imread("test_image.jpg", 1)
cv2.imwrite("test_image.png", image)

I don't use python myself, but try looking into:
http://www.pythonware.com/products/pil/
import Image
im = Image.open("infile.png")
im.save("outfile.jpg")
(taken from http://mail.python.org/pipermail/python-list/2001-April/700256.html )

Use ImageMagick with python. (on a linux system) [duplicate]

This question already has answers here:
Can I access ImageMagick API with Python?
(3 answers)
Closed 9 years ago.
I want to define a function that "call" imagemagick to convert an image.
def convert(filein,fileout):
#imagemagick>convert filein fileout
How can I call and use imagemagick with Python?
I'm running on a linux system, imagemagick is installed, and I'm not using PIL.module because it doesn't handle PPM[p3].

Disclaimer: I am the author of Wand.
You can easily do that using Wand, a simple binding of ImageMagick for Python. For example, the following code converts a PNG image to a JPEG image:
from wand.image import Image
with Image(filename='in.png') as img:
img.format = 'jpeg'
img.save(filename='out.jpg')
See this tutorial as well.

Either use one of the shell interfaces of Python (os.system, subprocess.Popen) to call the imagemagick binary, or try out PythonMagick.

I would suggest u use subprocess it is safer
import subprocess
params = ['convert', 'src_file', 'result_file']
subprocess.check_call(params)

I have not used image magic but you could use os.system to call a shell command:
import os
os.system('imagemagick-converting-command filein fileout')
I suggest you go with PythonMagic as Creshal said. It is provided by ImageMagic and thus must be one of the best port available for python.