Source code for smqtk.algorithms.image_io.pil_io

import numpy

from six import BytesIO

from smqtk.algorithms import ImageReader
from smqtk.utils.image import crop_in_bounds

    import PIL.Image
except ImportError:

[docs]class PilImageReader (ImageReader): """ Image reader that uses PIL to load the image. This implementation may additionally raise an ``IOError`` when failing to to load an image. """
[docs] @classmethod def is_usable(cls): return IMPORT_SUCCESS
def __init__(self, explicit_mode=None): """ Image reader that uses PIL to load the image. This reader returns an image matrix in [height, width] or [height, width, channel] dimension format, depending on source or explicit image mode requested. :param None|str explicit_mode: Optional explicit PIL Image mode to convert the image to before converting into a matrix. This should be one of the `PIL concept modes`_. :raises ValueError: The provided ``explicit_mode`` was not a valid mode string according to ``PIL.Image.MODES``. .. _PIL concept modes: concepts.html#concept-modes """ super(PilImageReader, self).__init__() if explicit_mode and explicit_mode not in PIL.Image.MODES: raise ValueError("Given explicit image mode was not a valid mode " "as reported by ``PIL.Image.MODES``. Given '{}'. " "Available modes: {}." .format(explicit_mode, PIL.Image.MODES)) self._explicit_mode = explicit_mode
[docs] def get_config(self): return { 'explicit_mode': self._explicit_mode, }
[docs] def valid_content_types(self): # Explicitly load standard file format drivers. # - confirmed idempotent from at least version 5.3.0 # TODO: get access to lazy-loaded file format driver extensions? PIL.Image.preinit() return set(PIL.Image.MIME.values())
def _load_as_matrix(self, data_element, pixel_crop=None): """ Internal method to be implemented that attempts loading an image from the given data element and returning it as an image matrix. Pre-conditions: - ``pixel_crop`` has a non-zero volume and is composed of integer types. :param smqtk.representation.DataElement data_element: DataElement to load image data from. :param None|smqtk.representation.AxisAlignedBoundingBox pixel_crop: Optional pixel crop region to load from the given data. If this is provided it must represent a valid sub-region within the loaded image, otherwise a RuntimeError is raised. :raises RuntimeError: A crop region was specified but did not specify a valid sub-region of the image. :return: Numpy ndarray of the image data. Specific return format is implementation dependant. :rtype: numpy.ndarray """ # We may have to add a mode where we use write_temp and load from that # if loading large images straight from bytes-in-memory is a problem # and that approach actually alleviates anything. # Catch and raise alternate IOError exception for readability. try: #: :type: PIL.Image.Image img = except IOError as ex: ex_str = str(ex) if 'cannot identify image file' in ex_str: raise IOError("Failed to identify image from bytes provided " "by {}".format(data_element)) else: # pass through other exceptions raise if pixel_crop: if not crop_in_bounds(pixel_crop, *img.size): raise RuntimeError("Crop provided not within input image. " "Image shape: {}, crop: {}" .format(img.size, pixel_crop)) img = img.crop(pixel_crop.min_vertex.tolist() + pixel_crop.max_vertex.tolist()) # If the loaded image is not already the optionally provided # explicit mode, convert it. if self._explicit_mode and img.mode != self._explicit_mode: img = img.convert(mode=self._explicit_mode) # noinspection PyTypeChecker return numpy.asarray(img)