[svn] Switch from photologue to imagekit. Less bloat.

Copied from http://cucc@cucc.survex.com/svn/trunk/expoweb/troggle/, rev. 8338 by cucc @ 5/11/2009 3:08 AM

imagekit/models.py

@@ -0,0 +1,136 @@
+import os
+from datetime import datetime
+from django.conf import settings
+from django.core.files.base import ContentFile
+from django.db import models
+from django.db.models.base import ModelBase
+from django.utils.translation import ugettext_lazy as _
+
+from imagekit import specs
+from imagekit.lib import *
+from imagekit.options import Options
+from imagekit.utils import img_to_fobj
+
+# Modify image file buffer size.
+ImageFile.MAXBLOCK = getattr(settings, 'PIL_IMAGEFILE_MAXBLOCK', 256 * 2 ** 10)
+
+# Choice tuples for specifying the crop origin.
+# These are provided for convenience.
+CROP_HORZ_CHOICES = (
+    (0, _('left')),
+    (1, _('center')),
+    (2, _('right')),
+)
+
+CROP_VERT_CHOICES = (
+    (0, _('top')),
+    (1, _('center')),
+    (2, _('bottom')),
+)
+
+
+class ImageModelBase(ModelBase):
+    """ ImageModel metaclass
+    
+    This metaclass parses IKOptions and loads the specified specification
+    module.
+    
+    """
+    def __init__(cls, name, bases, attrs):
+        parents = [b for b in bases if isinstance(b, ImageModelBase)]
+        if not parents:
+            return
+        user_opts = getattr(cls, 'IKOptions', None)
+        opts = Options(user_opts)
+        try:
+            module = __import__(opts.spec_module,  {}, {}, [''])
+        except ImportError:
+            raise ImportError('Unable to load imagekit config module: %s' % \
+                opts.spec_module)    
+        for spec in [spec for spec in module.__dict__.values() \
+                     if isinstance(spec, type) \
+                     and issubclass(spec, specs.ImageSpec) \
+                     and spec != specs.ImageSpec]:
+            setattr(cls, spec.name(), specs.Descriptor(spec))
+            opts.specs.append(spec)
+        setattr(cls, '_ik', opts)
+
+
+class ImageModel(models.Model):
+    """ Abstract base class implementing all core ImageKit functionality
+    
+    Subclasses of ImageModel are augmented with accessors for each defined
+    image specification and can override the inner IKOptions class to customize
+    storage locations and other options.
+    
+    """
+    __metaclass__ = ImageModelBase
+
+    class Meta:
+        abstract = True
+        
+    class IKOptions:
+        pass
+        
+    def admin_thumbnail_view(self):
+        if not self._imgfield:
+            return None
+        prop = getattr(self, self._ik.admin_thumbnail_spec, None)
+        if prop is None:
+            return 'An "%s" image spec has not been defined.' % \
+              self._ik.admin_thumbnail_spec
+        else:
+            if hasattr(self, 'get_absolute_url'):
+                return u'<a href="%s"><img src="%s"></a>' % \
+                    (self.get_absolute_url(), prop.url)
+            else:
+                return u'<a href="%s"><img src="%s"></a>' % \
+                    (self._imgfield.url, prop.url)
+    admin_thumbnail_view.short_description = _('Thumbnail')
+    admin_thumbnail_view.allow_tags = True
+    
+    @property
+    def _imgfield(self):
+        return getattr(self, self._ik.image_field)
+
+    def _clear_cache(self):
+        for spec in self._ik.specs:
+            prop = getattr(self, spec.name())
+            prop._delete()
+
+    def _pre_cache(self):
+        for spec in self._ik.specs:
+            if spec.pre_cache:
+                prop = getattr(self, spec.name())
+                prop._create()
+
+    def save(self, clear_cache=True, *args, **kwargs):
+        is_new_object = self._get_pk_val is None
+        super(ImageModel, self).save(*args, **kwargs)
+        if is_new_object:
+            clear_cache = False
+            spec = self._ik.preprocessor_spec
+            if spec is not None:
+                newfile = self._imgfield.storage.open(str(self._imgfield))
+                img = Image.open(newfile)
+                img = spec.process(img, None)
+                format = img.format or 'JPEG'
+                if format != 'JPEG':
+                    imgfile = img_to_fobj(img, format)
+                else:
+                    imgfile = img_to_fobj(img, format,
+                                          quality=int(spec.quality),
+                                          optimize=True)
+                content = ContentFile(imgfile.read())
+                newfile.close()
+                name = str(self._imgfield)
+                self._imgfield.storage.delete(name)
+                self._imgfield.storage.save(name, content)
+        if clear_cache and self._imgfield != '':
+            self._clear_cache()
+            self._pre_cache()
+
+    def delete(self):
+        assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname)
+        self._clear_cache()
+        models.Model.delete(self)