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Viewing changes to wlggz/fields.py

  • Committer: timo
  • Date: 2010-06-03 14:21:21 UTC
  • mto: This revision was merged to the branch mainline in revision 218.
  • Revision ID: timo@athin-20100603142121-65pr9u44g3lsmxoi
add first version of wlggz app

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wlggz/fields.py
 
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"""
 
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Details about AutoOneToOneField:
 
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    http://softwaremaniacs.org/blog/2007/03/07/auto-one-to-one-field/
 
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"""
 
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from StringIO import StringIO
 
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import logging
 
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from django.db.models import OneToOneField
 
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from django.db.models.fields.related import SingleRelatedObjectDescriptor 
 
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from django.db import models
 
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from django.core.files.uploadedfile import SimpleUploadedFile
 
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class AutoSingleRelatedObjectDescriptor(SingleRelatedObjectDescriptor):
 
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    def __get__(self, instance, instance_type=None):
 
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        try:
 
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            return super(AutoSingleRelatedObjectDescriptor, self).__get__(instance, instance_type)
 
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        except self.related.model.DoesNotExist:
 
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            obj = self.related.model(**{self.related.field.name: instance})
 
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            obj.save()
 
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            return obj
 
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class AutoOneToOneField(OneToOneField):
 
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    """
 
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    OneToOneField creates dependent object on first request from parent object
 
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    if dependent oject has not created yet.
 
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    """
 
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    def contribute_to_related_class(self, cls, related):
 
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        setattr(cls, related.get_accessor_name(), AutoSingleRelatedObjectDescriptor(related))
 
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        #if not cls._meta.one_to_one_field:
 
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            #cls._meta.one_to_one_field = self
 
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class ExtendedImageField(models.ImageField):
 
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    """
 
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    Extended ImageField that can resize image before saving it.
 
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    """
 
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    def __init__(self, *args, **kwargs):
 
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        self.width = kwargs.pop('width', None)
 
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        self.height = kwargs.pop('height', None)
 
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        super(ExtendedImageField, self).__init__(*args, **kwargs)
 
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    def save_form_data(self, instance, data):
 
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        if data and self.width and self.height:
 
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            if instance.avatar:
 
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                instance.avatar.delete()
 
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            content = self.resize_image(data.read(), width=self.width, height=self.height)
 
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            data = SimpleUploadedFile(instance.user.username + ".png", content, data.content_type)
 
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            super(ExtendedImageField, self).save_form_data(instance, data)
 
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    def resize_image(self, rawdata, width, height):
 
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        """
 
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        Resize image to fit it into (width, height) box.
 
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        """
 
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        try:
 
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            import Image
 
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        except ImportError:
 
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            from PIL import Image
 
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        image = Image.open(StringIO(rawdata))
 
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        try:
 
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            oldw, oldh = image.size
 
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            if oldw > width or oldh > height:
 
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                if oldw >= oldh:
 
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                    x = int(round((oldw - oldh) / 2.0))
 
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                    image = image.crop((x, 0, (x + oldh) - 1, oldh - 1))
 
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                else:
 
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                    y = int(round((oldh - oldw) / 2.0))
 
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                    image = image.crop((0, y, oldw - 1, (y + oldw) - 1))
 
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                image = image.resize((width, height), resample=Image.ANTIALIAS)
 
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        except Exception, err:
 
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            logging.error(err)
 
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            return ''
 
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        string = StringIO()
 
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        image.save(string, format='PNG')
 
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        return string.getvalue()