Django PIL : IOError Cannot identify image file - python

I'm learning Python and Django.
An image is provided by the user using forms.ImageField(). Then I have to process it in order to create two different sized images.
When I submit the form, Django returns the following error:
IOError at /add_event/
cannot identify image file
I call the resize function:
def create_event(owner_id, name, image):
image_thumb = image_resizer(image, name, '_t', 'events', 180, 120)
image_medium = image_resizer(image, name, '_m', 'events', 300, 200)
I get en error when image_resizer is called for the second time:
def image_resizer(image, name, size, app_name, length, height):
im = Image.open(image)
if im.mode != "RGB":
im = im.convert("RGB")
im = create_thumb(im, length, height)
posit = str(MEDIA_ROOT)+'/'+app_name+'/'
image_2 = im
image_name = name + size +'.jpg'
imageurl = posit + image_name
image_2.save(imageurl,'JPEG',quality=80)
url_image='/'+app_name+'/'+image_name
return url_image
Versions:
Django 1.3.1
Python 2.7.1
PIL 1.1.7
I'm trying to find the problem, but i don't know what to do. Thank you in advanced!
EDIT
I solved rewriting the function; now it creates the different images in batch:
I call the resize function:
url_array = image_resizer.resize_batch(image, image_name, [[180,120,'_t'], [300,200,'_m']], '/events/')
so:
image_thumb = url_array[0]
image_medium = url_array[1]
and the resize function:
def resize_batch(image, name, size_array, position):
im = Image.open(image)
if im.mode != "RGB":
im = im.convert("RGB")
url_array = []
for size in size_array:
new_im = create_thumb(im, size[0], size[1])
posit = str(MEDIA_ROOT) + position
image_name = name + size[2] +'.jpg'
imageurl = posit + image_name
new_im.save(imageurl,'JPEG',quality=90)
new_url_array = position + image_name
url_array.append(new_url_array)
return url_array
Thanks to all!

As ilvar asks in the comments, what kind of object is image? I'm going to assume for the purposes of this answer that it's the file property of a Django ImageField that comes from a file uploaded by a remote user.
After a file upload, the object you get in the ImageField.file property is a TemporaryUploadedFile object that might represent a file on disk or in memory, depending on how large the upload was. This object behaves much like a normal Python file object, so after you have read it once (to make the first thumbnail), you have reached the end of the file, so that when you try to read it again (to make the second thumbnail), there's nothing there, hence the IOError. To make a second thumbnail, you need to seek back to the beginning of the file. So you could add the line
image.seek(0)
to the start of your image_resizer function.
But this is unnecessary! You have this problem because you are asking the Python Imaging Library to re-read the image for each new thumbnail you want to create. This is a waste of time: better to read the image just once and then create all the thumbnails you want.

I'm guessing that is a TemporaryUploadedFile ... find this with type(image).
import cStringIO
if isinstance(image, TemporaryUploadedFile):
temp_file = open(image.temporary_file_path(), 'rb+')
content = cStringIO.StringIO(temp_file.read())
image = Image.open(content)
temp_file.close()
I'm not 100% sure of the code above ... comes from 2 classes I've got for image manipulation ... but give it a try.
If is a InMemoryUploadedFile your code should work!

Related

How to get DPI value of an image in Python/Django

I am trying to extract the Dpi value of an image Using python in one of my django powered web application.I am using following function to achieve my desired output that is the Dpi value of an image but i am facing an exception.
This is the Function to get DPI value of an Image
def get_exif_data(fname):
"""Get embedded EXIF data from image file."""
ret = {}
try:
img = Image.open(fname)
if hasattr( img, '_getexif' ):
exifinfo = img._getexif()
if exifinfo != None:
for tag, value in exifinfo.items():
decoded = TAGS.get(tag, tag)
ret[decoded] = value
except IOError:
print 'IOERROR ' + fname
return ret
and this is the view where i have used that above function to get the DPI value of an Image.
def get_dpi(request,image_id):
image = get_object_or_404(Photo,pk = image_id)
img = Image.open(image.photo)
dpi_info = get_exif_data(img)
context = RequestContext(request)
ctx = {'dpi':dpi_info}
return render_to_response('photo/download_image.html',ctx,context)
but i am facing the following exception
To begin, I have to ask why you want the DPI resolution. It's just a tag and doesn't really mean anything unless you are outputing to physical media. A 1000x1000 pixel image can be 10x10 at 100dpi or 100x100 at 10dpi, but it's still exactly the same image. Exactly the same pixels. It's hard to imagine scenarios where img.size doesn't give you everything you need.
Having said that, if you want to get the exif tags for resolution try XResolution from PIL.ExifTags:
import Image
from PIL.ExifTags import TAGS
img = Image.open("path/to/.jpg")
info = img._getexif()
exifObj = {}
if info != None:
for tag, value in info.items():
decoded = TAGS.get(tag, tag)
exifObj[decoded] = value
exifObj now either empty or equals something like:
{'YResolution': (720000, 10000), 'BitsPerSample': (8, 8, 8), 'ImageLength': 713, 'Orientation': 1, 'Copyright': 'Mark Meyer Photography', 'ExifImageWidth': 950, 'ExifImageHeight': 713, 'ColorSpace': 1, 'ResolutionUnit': 2, 'DateTime': '2015:01:30 21:37:51', 'XResolution': (720000, 10000), 'ExifOffset': 296, 'PhotometricInterpretation': 2, 'ExifVersion': '0221', 'Artist': 'MarkM', 'ImageWidth': 950, 'SamplesPerPixel': 3, 'Software': 'Adobe Photoshop CC 2014 (Macintosh)'}
DPI is:
exifObj['XResolution'][0]/exifObj['XResolution'][1]
72DPI in this case.
It's not clear in your example how you are trying to access the DPI value for the context. You're getting an attribute error, so maybe in your template you are trying to access ctx.dpi or something similar which doesn't exist.
Almost I spend searching 3 hours for this. At last I find it out, how we can find dpi of an image or pdf using fitz library, you can download using this command pip install PyMuPDF and pip install fitz.
If you want to know more about this process you can check it out official documentation. If you found useful upvote it!
def dpi_finder(link : str) -> int:
doc = fitz.open(link) # opening a image or pdf.
page = doc.load_page(0) # getting first page
pix = page.get_pixmap() # getting the pixamp
return pix.xres # it will give the dpi for horizontal resolution

Generate a image which produces gif like effect

I am trying to generate a image which produces gif like effect by flushing the response continuously to the browser, I am relatively new to django/python and tried with following code testing for both text and image. The generator for text works fine but in case of image only first version of image is being generated.
I tried searching but can't find anything on this. I am confused how to proceed with this or if this is at all possible with django or If the idea is conceptually wrong.
Image Generator :
def refreshx():
from PIL import Image
from PIL import ImageFont
from PIL import ImageDraw
size = (1000,500)
im = Image.new('RGB', size)
draw = ImageDraw.Draw(im)
red = (255,255,255)
text_pos = (10,30)
draw.text(text_pos, str(datetime.datetime.today()), fill=red)
buffer = StringIO.StringIO()
im.save(buffer, 'PNG')
yield buffer.getvalue()
time.sleep(5)
buffers = StringIO.StringIO()
ims = Image.new('RGB', size)
draws = ImageDraw.Draw(ims)
text_poss = (30,80)
draws.text(text_poss, 'dasdasdsa', fill=red)
print 'been there'
ims.save(buffers, 'PNG')
yield buffers.getvalue()
Text Generator :
def testgenerator():
yield str(datetime.datetime.today())
time.sleep(5)
yield str(datetime.datetime.today())
View Function :
def test(request):
#return HttpResponse(testgenerator());
return HttpResponse(refreshx(), mimetype="image/png")
EDIT :
I learned while researching that there's a concept called gifsocket, I'm looking into it..please suggest if anyone has experience with these

Python Image (PIL) library not resizing properly per kwargs

Here is my code:
import Image
import sys
import json
if __name__ == '__main__':
args = json.loads(sys.argv[1])
srcPath = args.get('srcPath')
image = Image.open(srcPath)
sizes = {}
for variant_name, dimensions in args.get('sizes').items():
if '%' in dimensions:
sizes[variant_name] = image.size
else:
width = int(dimensions.split('x')[0])
height = int(dimensions.split('x')[1])
widthAndHeight = (width, height)
sizes[variant_name] = widthAndHeight
for key, val in sizes.items():
imageName = key + '.' + srcPath.split('.')[1]
convertedImage = image.resize(val, Image.ANTIALIAS)
image.save(imageName)
print 'done'
And I'm calling it with:
python image.py '{"sizes":{"large":"200x150","orig":"100%x100%"},"srcPath":"/Users/bobcobb/Desktop/avocado.png"}'
If the argument 100%x100% is passed in, then I want to resize to the original size, otherwise, I want to resize to the passed in size. So the above code would generate 2 images (one original, the other 200x150).
Right now, it just saves the image as the original size for both. How can I fix this?
Your problem is that the resized image is assigned to convertedImage, but you save the original image (at the new filename).
So changing this line
image.save(imageName)
into
convertedImage.save(imageName)
solves this problem.

Django Image upload and resize

I have a standard Django form with an image field. When the image is uploaded, I would like to make sure that the image is no larger than 300px by 300px. Here is my code:
def post(request):
if request.method == 'POST':
instance = Product(posted_by=request.user)
form = ProductModelForm(request.POST or None, request.FILES or None)
if form.is_valid():
new_product = form.save(commit=False)
if 'image' in request.FILES:
img = Image.open(form.cleaned_data['image'])
img.thumbnail((300, 300), Image.ANTIALIAS)
# this doesnt save the contents here...
img.save(new_product.image)
# ..because this prints the original width (2830px in my case)
print new_product.image.width
The problem I am facing is, it is not clear to me how I get the Image type converted to the type that ImageField type.
From the documentation on ImageField's save method:
Note that the content argument should be an instance of django.core.files.File, not Python's built-in file object.
This means you would need to convert the PIL.Image (img) to a Python file object, and then convert the Python object to a django.core.files.File object. Something like this (I have not tested this code) might work:
img.thumbnail((300, 300), Image.ANTIALIAS)
# Convert PIL.Image to a string, and then to a Django file
# object. We use ContentFile instead of File because the
# former can operate on strings.
from django.core.files.base import ContentFile
djangofile = ContentFile(img.tostring())
new_product.image.save(filename, djangofile)
There you go, just change a little bit to suit your need:
class PhotoField(forms.FileField, object):
def __init__(self, *args, **kwargs):
super(PhotoField, self).__init__(*args, **kwargs)
self.help_text = "Images over 500kb will be resized to keep under 500kb limit, which may result in some loss of quality"
def validate(self,image):
if not str(image).split('.')[-1].lower() in ["jpg","jpeg","png","gif"]:
raise ValidationError("File format not supported, please try again and upload a JPG/PNG/GIF file")
def to_python(self, image):
try:
limit = 500000
num_of_tries = 10
img = Image.open(image.file)
width, height = img.size
ratio = float(width) / float(height)
upload_dir = settings.FILE_UPLOAD_TEMP_DIR if settings.FILE_UPLOAD_TEMP_DIR else '/tmp'
tmp_file = open(os.path.join(upload_dir, str(uuid.uuid1())), "w")
tmp_file.write(image.file.read())
tmp_file.close()
while os.path.getsize(tmp_file.name) > limit:
num_of_tries -= 1
width = 900 if num_of_tries == 0 else width - 100
height = int(width / ratio)
img.thumbnail((width, height), Image.ANTIALIAS)
img.save(tmp_file.name, img.format)
image.file = open(tmp_file.name)
if num_of_tries == 0:
break
except:
pass
return image
Source: http://james.lin.net.nz/2012/11/19/django-snippet-reduce-image-size-during-upload/
How about using standard image field https://github.com/humanfromearth/django-stdimage
Here is an app that can take care of that: django-smartfields
from django.db import models
from smartfields import fields
from smartfields.dependencies import FileDependency
from smartfields.processors import ImageProcessor
class Product(models.Model):
image = fields.ImageField(dependencies=[
FileDependency(processor=ImageProcessor(
scale={'max_width': 300, 'max_height': 300}))
])
Try my solution here: https://stackoverflow.com/a/25222000/3731039
Highlight
Using Pillow for image processing (two packages required: libjpeg-dev, zlib1g-dev)
Using Model and ImageField as storage
Using HTTP POST or PUT with multipart/form
No need to save the file to disk manually.
Create multiple resolutions and stores their dimensions.
You can use my library django-sizedimagefield for this, it has no extra dependency and is very simple to use.

How do you convert a PIL `Image` to a Django `File`?

I'm trying to convert an UploadedFile to a PIL Image object to thumbnail it, and then convert the PIL Image object that my thumbnail function returns back into a File object. How can I do this?
The way to do this without having to write back to the filesystem, and then bring the file back into memory via an open call, is to make use of StringIO and Django InMemoryUploadedFile. Here is a quick sample on how you might do this. This assumes that you already have a thumbnailed image named 'thumb':
import StringIO
from django.core.files.uploadedfile import InMemoryUploadedFile
# Create a file-like object to write thumb data (thumb data previously created
# using PIL, and stored in variable 'thumb')
thumb_io = StringIO.StringIO()
thumb.save(thumb_io, format='JPEG')
# Create a new Django file-like object to be used in models as ImageField using
# InMemoryUploadedFile. If you look at the source in Django, a
# SimpleUploadedFile is essentially instantiated similarly to what is shown here
thumb_file = InMemoryUploadedFile(thumb_io, None, 'foo.jpg', 'image/jpeg',
thumb_io.len, None)
# Once you have a Django file-like object, you may assign it to your ImageField
# and save.
...
Let me know if you need more clarification. I have this working in my project right now, uploading to S3 using django-storages. This took me the better part of a day to properly find the solution here.
I've had to do this in a few steps, imagejpeg() in php requires a similar process. Not to say theres no way to keep things in memory, but this method gives you a file reference to both the original image and thumb (usually a good idea in case you have to go back and change your thumb size).
save the file
open it from filesystem with PIL,
save to a temp directory with PIL,
then open as a Django file for this to work.
Model:
class YourModel(Model):
img = models.ImageField(upload_to='photos')
thumb = models.ImageField(upload_to='thumbs')
Usage:
#in upload code
uploaded = request.FILES['photo']
from django.core.files.base import ContentFile
file_content = ContentFile(uploaded.read())
new_file = YourModel()
#1 - get it into the DB and file system so we know the real path
new_file.img.save(str(new_file.id) + '.jpg', file_content)
new_file.save()
from PIL import Image
import os.path
#2, open it from the location django stuck it
thumb = Image.open(new_file.img.path)
thumb.thumbnail(100, 100)
#make tmp filename based on id of the model
filename = str(new_file.id)
#3. save the thumbnail to a temp dir
temp_image = open(os.path.join('/tmp',filename), 'w')
thumb.save(temp_image, 'JPEG')
#4. read the temp file back into a File
from django.core.files import File
thumb_data = open(os.path.join('/tmp',filename), 'r')
thumb_file = File(thumb_data)
new_file.thumb.save(str(new_file.id) + '.jpg', thumb_file)
This is actual working example for python 3.5 and django 1.10
in views.py:
from io import BytesIO
from django.core.files.base import ContentFile
from django.core.files.uploadedfile import InMemoryUploadedFile
def pill(image_io):
im = Image.open(image_io)
ltrb_border = (0, 0, 0, 10)
im_with_border = ImageOps.expand(im, border=ltrb_border, fill='white')
buffer = BytesIO()
im_with_border.save(fp=buffer, format='JPEG')
buff_val = buffer.getvalue()
return ContentFile(buff_val)
def save_img(request)
if request.POST:
new_record = AddNewRecordForm(request.POST, request.FILES)
pillow_image = pill(request.FILES['image'])
image_file = InMemoryUploadedFile(pillow_image, None, 'foo.jpg', 'image/jpeg', pillow_image.tell, None)
request.FILES['image'] = image_file # really need rewrite img in POST for success form validation
new_record.image = request.FILES['image']
new_record.save()
return redirect(...)
Putting together comments and updates for Python 3+
from io import BytesIO
from django.core.files.base import ContentFile
import requests
# Read a file in
r = request.get(image_url)
image = r.content
scr = Image.open(BytesIO(image))
# Perform an image operation like resize:
width, height = scr.size
new_width = 320
new_height = int(new_width * height / width)
img = scr.resize((new_width, new_height))
# Get the Django file object
thumb_io = BytesIO()
img.save(thumb_io, format='JPEG')
photo_smaller = ContentFile(thumb_io.getvalue())
To complete for those who, like me, want to couple it with Django's FileSystemStorage:
(What I do here is upload an image, resize it to 2 dimensions and save both files.
utils.py
def resize_and_save(file):
size = 1024, 1024
thumbnail_size = 300, 300
uploaded_file_url = getURLforFile(file, size, MEDIA_ROOT)
uploaded_thumbnail_url = getURLforFile(file, thumbnail_size, THUMBNAIL_ROOT)
return [uploaded_file_url, uploaded_thumbnail_url]
def getURLforFile(file, size, location):
img = Image.open(file)
img.thumbnail(size, Image.ANTIALIAS)
thumb_io = BytesIO()
img.save(thumb_io, format='JPEG')
thumb_file = InMemoryUploadedFile(thumb_io, None, file.name, 'image/jpeg', thumb_io.tell, None)
fs = FileSystemStorage(location=location)
filename = fs.save(file.name, thumb_file)
return fs.url(filename)
In views.py
if request.FILES:
fl, thumbnail = resize_and_save(request.FILES['avatar'])
#delete old profile picture before saving new one
try:
os.remove(BASE_DIR + user.userprofile.avatarURL)
except Exception as e:
pass
user.userprofile.avatarURL = fl
user.userprofile.thumbnailURL = thumbnail
user.userprofile.save()
Here is an app that can do that: django-smartfields
from django.db import models
from smartfields import fields
from smartfields.dependencies import FileDependency
from smartfields.processors import ImageProcessor
class ImageModel(models.Model):
image = fields.ImageField(dependencies=[
FileDependency(processor=ImageProcessor(
scale={'max_width': 150, 'max_height': 150}))
])
Make sure to pass keep_orphans=True to the field, if you want to keep old files, otherwise they are cleaned up upon replacement.
For those using django-storages/-redux to store the image file on S3, here's the path I took (the example below creates a thumbnail of an existing image):
from PIL import Image
import StringIO
from django.core.files.storage import default_storage
try:
# example 1: use a local file
image = Image.open('my_image.jpg')
# example 2: use a model's ImageField
image = Image.open(my_model_instance.image_field)
image.thumbnail((300, 200))
except IOError:
pass # handle exception
thumb_buffer = StringIO.StringIO()
image.save(thumb_buffer, format=image.format)
s3_thumb = default_storage.open('my_new_300x200_image.jpg', 'w')
s3_thumb.write(thumb_buffer.getvalue())
s3_thumb.close()

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