1 """

     2     State for thumbnails; derivates of Images

     3 """

     4 

     5 import filesystem

     6 

     7 import PIL.Image

     8 

     9 class Thumbnail (filesystem.File) :

    10     """

    11         A Thumbnail is a derivate of an Image, usually resized to some other size.

    12     """

    13 

    14     def __init__ (self, image, subdir, size) :

    15         """

    16             Initialize to link against the given `image`.

    17             

    18             `subdir` specifies the directory to store this thumbnail in.

    19             `size` determines the target resolution of the output thumbnail.

    20         """

    21 

    22         # our file path

    23         # XXX: this should be the binary fsname, not name

    24         super(Thumbnail, self).__init__(subdir.subnode(image.name))

    25 

    26         # store

    27         self.image = image

    28         self.size = size

    29 

    30     def stale (self) :

    31         """

    32             Tests if this thumbnail is stale

    33         """

    34         

    35         return self.older_than(self.image)

    36 

    37     def update (self) :

    38         """

    39             Render new output thumbnail

    40         """

    41         

    42         # load a copy of the PIL.Image, as .thumbnail mutates it

    43         thumb = self.image.pil_image.copy()

    44 

    45         # resample to given size

    46         thumb.thumbnail(self.size, resample=True)

    47 

    48         # and write out

    49         thumb.save(self.path)

    50