thumbnails in web2py

web2py_image.py

# -*- coding: utf-8 -*-

#######################################################################
#
# Put this file in yourapp/modules/images.py
#
# Given the model
#
# db.define_table("table_name", Field("picture", "upload"), Field("thumbnail", "upload"))
#
# # to resize the picture on upload
#
# from images import RESIZE
#
# db.table_name.picture.requires = RESIZE(200, 200)
#
# # to store original image in picture and create a thumbnail in 'thumbnail' field
#
# from images import THUMB
# db.table_name.thumbnail.compute = lambda row: THUMB(row.picture, 200, 200)

#########################################################################
from gluon import current

class RESIZE(object):
    def __init__(self, nx=160, ny=80, error_message=' image resize'):
        (self.nx, self.ny, self.error_message) = (nx, ny, error_message)

    def __call__(self, value):
        if isinstance(value, str) and len(value) == 0:
            return (value, None)
        from PIL import Image
        import cStringIO
        try:
            img = Image.open(value.file)
            img.thumbnail((self.nx, self.ny), Image.ANTIALIAS)
            s = cStringIO.StringIO()
            img.save(s, 'JPEG', quality=100)
            s.seek(0)
            value.file = s
        except:
            return (value, self.error_message)
        else:
            return (value, None)

def THUMB(image, nx=120, ny=120, gae=False, name='thumb'):
    if image:
        if not gae:
            request = current.request
            from PIL import Image
            import os
            img = Image.open(request.folder + 'uploads/' + image)
            img.thumbnail((nx, ny), Image.ANTIALIAS)
            root, ext = os.path.splitext(image)
            thumb = '%s_%s%s' % (root, name, ext)
            img.save(request.folder + 'uploads/' + thumb)
            return thumb
        else:
            return image