terom@85: """
terom@85:     State for thumbnails; derivates of Images
terom@85: """
terom@85: 
terom@85: import filesystem
terom@85: 
terom@85: import PIL.Image
terom@85: 
terom@85: class Thumbnail (filesystem.File) :
terom@85:     """
terom@85:         A Thumbnail is a derivate of an Image, usually resized to some other size.
terom@85:     """
terom@85: 
terom@85:     def __init__ (self, image, subdir, size) :
terom@85:         """
terom@85:             Initialize to link against the given `image`.
terom@85:             
terom@85:             `subdir` specifies the directory to store this thumbnail in.
terom@85:             `size` determines the target resolution of the output thumbnail.
terom@85:         """
terom@85: 
terom@95:         # our file path, image name inside of the given subdir
terom@95:         super(Thumbnail, self).__init__(subdir, image.fsname)
terom@85: 
terom@85:         # store
terom@85:         self.image = image
terom@85:         self.size = size
terom@85: 
terom@85:     def stale (self) :
terom@85:         """
terom@85:             Tests if this thumbnail is stale
terom@85:         """
terom@85:         
terom@95:         if self.image.older_than(self) :
terom@95:             # both exist and this is newer
terom@95:             return False
terom@95:         
terom@95:         else :
terom@95:             # this thumb doesn't exist or is older
terom@95:             return True
terom@85: 
terom@85:     def update (self) :
terom@85:         """
terom@85:             Render new output thumbnail
terom@85:         """
terom@85:         
terom@85:         # load a copy of the PIL.Image, as .thumbnail mutates it
terom@85:         thumb = self.image.pil_image.copy()
terom@85: 
terom@85:         # resample to given size
terom@85:         thumb.thumbnail(self.size, resample=True)
terom@85: 
terom@85:         # and write out
terom@85:         thumb.save(self.path)
terom@95: