Add images to finds (refs #1314)

* an abstract model class has been defined to manage image and thumbnail
  with resizing on the fly
* max size for images and thumbnails are set in project settings
* new field have been added to Find model to save images and thumbnails
* form and wizard of Find have been changed

1 files changed, 52 insertions, 0 deletions

diff --git a/ishtar_common/models.py b/ishtar_common/models.py
index 12b1b79f9..fc4cdbd17 100644
--- a/ishtar_common/models.py
+++ b/ishtar_common/models.py
@@ -20,10 +20,14 @@
 """
 Models description
 """
+from cStringIO import StringIO
 import datetime
+from PIL import Image
+import os
 
 from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.core.files.uploadedfile import SimpleUploadedFile
 from django.core.validators import validate_slug
 from django.utils.translation import ugettext_lazy as _, ugettext
 from django.utils.safestring import SafeUnicode, mark_safe
@@ -258,6 +262,54 @@ class GeneralType(models.Model):
             for child in cls._get_childs(item, dct, instances, exclude=exclude):
                 yield child
 
+class ImageModel(models.Model):
+    image = models.ImageField(upload_to="upload/", blank=True, null=True)
+    thumbnail = models.ImageField(upload_to='upload/thumbs/', blank=True,
+                                  null=True)
+    IMAGE_MAX_SIZE = settings.IMAGE_MAX_SIZE
+    THUMB_MAX_SIZE = settings.THUMB_MAX_SIZE
+
+    class Meta:
+        abstract = True
+
+    def has_changed(self, field):
+        if not self.pk:
+            return True
+        manager = getattr(self.__class__, 'objects')
+        old = getattr(manager.get(pk=self.pk), field)
+        return not getattr(self, field) == old
+
+    def create_thumb(self, image, size):
+        """Returns the image resized to fit inside a box of the given size"""
+        image.thumbnail(size, Image.ANTIALIAS)
+        temp = StringIO()
+        image.save(temp, 'jpeg')
+        temp.seek(0)
+        return SimpleUploadedFile('temp', temp.read())
+
+    def save(self, *args, **kwargs):
+        # manage images
+        if self.has_changed('image'):
+            # convert to jpg
+            filename = os.path.splitext(os.path.split(self.image.name)[-1])[0]
+            filename = "%s.jpg" % filename
+            image = Image.open(self.image.file)
+
+            # convert to RGB
+            if image.mode not in ('L', 'RGB'):
+                image = image.convert('RGB')
+
+            # resize if necessary
+            self.image.save(filename,
+                            self.create_thumb(image, self.IMAGE_MAX_SIZE),
+                            save=False)
+
+            # save the thumbnail
+            self.thumbnail.save('_%s' % filename,
+                             self.create_thumb(image, self.THUMB_MAX_SIZE),
+                             save=False)
+        super(ImageModel, self).save(*args, **kwargs)
+
 class HistoryError(Exception):
     def __init__(self, value):
         self.value = value