Source code for mg.utils.photo.resizer.base

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# This file is part of Media Gallery, GNU GPLv2.
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__author__ = "Media Gallery contributors <mg@lists.ssji.net>"
__copyright__ = "(c) 2010"
__credits__ = ["Dimitri Refauvelet", "Nicolas Pouillon"]

__all__ = ["ResizerBase"]

class ResizerBase:
    """
    ResizerBase is a tool to resize images in an automated way.  Whatever
    the parameters, aspect ratio of image wont be modified, therefore
    image wont be deformed.
    """

    LETTERBOX = 1
    """
    Make the output image contain the whole input image, adding black
    borders if necessary
    """
    
    PAN_SCAN = 2
    """
    Fill the whole output image size with input image, fitting the
    shortest side of the image. Longest side of the input image may be
    partly discarded.
    """
    
    SCALE = 3
    """
    Scale input image to fit in the output bounding box. Resulting
    image size may be smaller than given output size.
    """
    
    
    def __init__(self, **params):
        """
        Creates a new ResizerBase. This may initialize global states.

        :param params: Parameters passed to set_output_size verbatim.
        """
        defaults = dict(
            size = (100, 100),
            mode = self.SCALE,
            )
        defaults.update(params)
        self.set_output_size(**defaults)

    def set_output_size(self, size, mode):
        """
        Sets the output parameters

        :param size: Output size
        :param mode: Mode of resizing, in ``LETTERBOX``, ``PAN_SCAN``
                     or ``SCALE``.
        """

    def resize(self,
               output_filename, input_filename,
               center = None, rot_count = 0):
        """
        Opens the given file as source image to resize, and
        save its resized version according to parameters.

        :param output_filename: Path to an image file to save
                                resized version to

        :param input_filename: Path to an image file to open

        :param center: Optional coords of center of interest of image.
                       If ommitted, image is centered normally. Only
                       relevant for ``PAN_SCAN`` mode. See
                       :ref:`fitting-modes` for more information.

        :param rot_count: Count of 90-degree rotations to apply to
                          image, clockwise. This transformation
                          changes nothing to the output image aspect.
                          Rotation is achived before fitting bounding
                          boxes.
        """