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"""

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    Rendering images as thumbnails/previews.

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"""

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import PIL.Image

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class RenderMachine (object) :

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    """

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        RAWR! I'm the render machine!

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        TODO: use multithreaded rendering (PIL supports it)

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    """

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    def __init__ (self, config) :

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        """

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            Use the given Configuration object's settings for rendering

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        """

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        self.config = config

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    def render_out (self, image, size, file) :

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        """

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            Creates a thumbnail from the given Image of the given `size`, and saves it at `out`.

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            Returns the file for convenience

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        """

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        # load the PIL.Image

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        img = image.image

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        # we need to create a copy, as .thumbnail mutates the Image

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        img_out = img.copy()

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        # then resample to given size

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        img_out.thumbnail(size, resample=True)

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        # and write out

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        img_out.save(file.path)

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        return file

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    def render_lazy (self, image, size, out) :

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        """

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            Renders the given image with render_out if `out` does not yet exist or is older than image.

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        """

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        # stat the output file

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        out_stat = out.stat(soft=True)

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        # compare

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        if not out_stat or out_stat.st_mtime < image.stat.st_mtime :

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            # render anew

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            return self.render_out(image, size, out)

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        else :

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            # already rendered

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            return out