[+] Add a1 files

assignments/a1/a1_part4.py

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+"""CSC110 Fall 2021 Assignment 1, Part 4
+
+Instructions (READ THIS FIRST!)
+===============================
+
+Please follow the instructions in the assignment handout to complete this file.
+
+Copyright and Usage Information
+===============================
+
+This file is provided solely for the personal and private use of students
+taking CSC110 at the University of Toronto St. George campus. All forms of
+distribution of this code, whether as given or with any changes, are
+expressly prohibited. For more information on copyright for CSC110 materials,
+please consult our Course Syllabus.
+
+This file is Copyright (c) 2021 Mario Badr and Tom Fairgrieve.
+"""
+import random
+
+import a1_image
+
+
+def maximize_channels(old_pixel: tuple, value: int) -> tuple:
+    """Return a new pixel that has colour channels set to the larger of value or the corresponding
+    colour channel in old_pixel.
+
+    >>> example_pixel = (100, 12, 155)
+    >>> maximize_channels(example_pixel, 128)
+    (128, 128, 155)
+    """
+
+
+def divide_channels(old_pixel: tuple, denominator: int) -> tuple:
+    """Return a new pixel that has colour channels set to the quotient from dividing the
+    corresponding colour channel in old_pixel by denominator.
+
+    >>> example_pixel = (100, 12, 155)
+    >>> divide_channels(example_pixel, 2)
+    (50, 6, 77)
+    """
+
+
+def add_pepper(pixel_data: list, k: int) -> list:
+    """Return a new list of pixels formed from the corresponding pixels in pixel_data that has some
+    randomly chosen black pixels.
+
+    The chance that a new pixel will be black is based on k. The probability that a pixel is
+    black is to be : 1 / (k + 1)
+
+    Assume that k >= 0.
+
+    You must use the divide_channels function (above).
+
+    Hint: use the function random.choice to choose from a list of denominators. What denominator,
+    passed to divide_channels, causes a pixel to not change its colour? What denominator causes a
+    pixel to become black?
+
+    Because of the randomness, we can't specify an exact doctest.
+    """
+
+
+def add_salt(pixel_data: list, k: int) -> list:
+    """Return a new list of pixels formed from the corresponding pixels in pixel_data that has some
+    randomly chosen white pixels.
+
+    The chance that a new pixel will be white is based on k. The probability that a pixel is
+    white is to be : 1 / (k + 1)
+
+    Assume that k >= 0.
+
+    You must use the maximize_channels function (above).
+
+    Hint: use the function random.choice to choose from a list of values. What value, passed to
+    maximize_channels, causes a pixel to not change its colour? What value causes a pixel to become
+    white?
+
+    Because of the randomness, we can't specify an exact doctest.
+    """
+
+
+def add_salt_and_pepper(pixel_data: list, k: int) -> list:
+    """Return a new list of pixels formed from the corresponding pixels in pixel_data
+    that has some randomly chosen white pixels and some randomly chosen black pixels.
+
+    You must use the add_pepper then add_salt functions, in that order, with both using noise
+    probabilities determined by k.
+
+    Because of the randomness, we can't specify an exact doctest.
+    """
+
+
+def run_salt_and_pepper_example(source: str, destination: str, k: int) -> None:
+    """Add salt and pepper noise to an example image file at source and save the result in
+    destination, where noisiness is a function of k.
+
+    You can run this function with an image of your choice. Make sure the image is not too large or
+    this will take a long time.
+    """
+    original_pixel_data, width, height = a1_image.load_image(source)
+    noisy_pixel_data = add_salt_and_pepper(original_pixel_data, k)
+    a1_image.save_image(destination, noisy_pixel_data, width, height)
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+
+    # When you are ready to check your work with python_ta, uncomment the following lines.
+    # (Delete the "#" and space before each line.)
+    # import python_ta
+    # python_ta.check_all(config={
+    #     'extra-imports': ['random', 'a1_image'],
+    #     'max-line-length': 100
+    # })