django-imagekit/imagekit/specs.py

136 lines
4.1 KiB
Python

""" ImageKit image specifications
All imagekit specifications must inherit from the ImageSpec class. Models
inheriting from ImageModel will be modified with a descriptor/accessor for each
spec found.
"""
import os
from StringIO import StringIO
from imagekit import processors
from imagekit.lib import *
from imagekit.utils import img_to_fobj
from django.core.files.base import ContentFile
class ImageSpec(object):
pre_cache = False
quality = 70
increment_count = False
processors = []
@classmethod
def name(cls):
return getattr(cls, 'access_as', cls.__name__.lower())
@classmethod
def process(cls, image, obj):
fmt = image.format
img = image.copy()
for proc in cls.processors:
img, fmt = proc.process(img, fmt, obj)
img.format = fmt
return img, fmt
class Accessor(object):
def __init__(self, obj, spec):
self._img = None
self._fmt = None
self._obj = obj
self.spec = spec
def _get_imgfile(self):
format = self._img.format or 'JPEG'
if format != 'JPEG':
imgfile = img_to_fobj(self._img, format)
else:
imgfile = img_to_fobj(self._img, format,
quality=int(self.spec.quality),
optimize=True)
return imgfile
def _create(self):
if self._obj._imgfield:
if self._exists():
return
# process the original image file
try:
fp = self._obj._imgfield.storage.open(self._obj._imgfield.name)
except IOError:
return
fp.seek(0)
fp = StringIO(fp.read())
self._img, self._fmt = self.spec.process(Image.open(fp), self._obj)
# save the new image to the cache
content = ContentFile(self._get_imgfile().read())
self._obj._storage.save(self.name, content)
def _delete(self):
if self._obj._imgfield:
self._obj._storage.delete(self.name)
def _exists(self):
if self._obj._imgfield:
return self._obj._storage.exists(self.name)
@property
def name(self):
if self._obj._imgfield.name:
filepath, basename = os.path.split(self._obj._imgfield.name)
filename, extension = os.path.splitext(basename)
for processor in self.spec.processors:
if issubclass(processor, processors.Format):
extension = processor.extension
cache_filename = self._obj._ik.cache_filename_format % \
{'pk': self._obj.pk,
'filename': filename,
'specname': self.spec.name(),
'extension': extension.lstrip('.')}
if callable(self._obj._ik.cache_dir):
return self._obj._ik.cache_dir(self._obj, filepath,
cache_filename)
else:
return os.path.join(self._obj._ik.cache_dir, filepath,
cache_filename)
@property
def url(self):
if not self.spec.pre_cache:
self._create()
if self.spec.increment_count:
fieldname = self._obj._ik.save_count_as
if fieldname is not None:
current_count = getattr(self._obj, fieldname)
setattr(self._obj, fieldname, current_count + 1)
self._obj.save(clear_cache=False)
return self._obj._storage.url(self.name)
@property
def file(self):
self._create()
return self._obj._storage.open(self.name)
@property
def image(self):
if not self._img:
self._create()
if not self._img:
self._img = Image.open(self.file)
return self._img
@property
def width(self):
return self.image.size[0]
@property
def height(self):
return self.image.size[1]
class Descriptor(object):
def __init__(self, spec):
self._spec = spec
def __get__(self, obj, type=None):
return Accessor(obj, self._spec)