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Currying Practice

Doc2Doc should include a feature for image resizing, allowing users to adjust image dimensions to specified ranges. This ensures that images in documents fit and aren't freakishly large or hilariously small.

Assignment

Complete the new_resizer function using currying. It should make sure the image dimensions are never smaller than the minimum width and height, or larger than the maximum width and height specified.

Check the example below to see how the function is intended to be called.

Define an inner function that takes two optional integer inputs, min_width and min_height, both with default values of 0.
In the inner function:
1. If min_width is more than max_width, or min_height is more than max_height, raise an exception: "minimum size cannot exceed maximum size"
2. Define an innermost function that takes two integer inputs, width and height. In the innermost function:
  1. Use the built-in min and max functions to reduce width if it's above max_width, or to increase it if it's below min_width. (See the tip below for info about how this works.)
  2. Do the same for height, making sure it's between min_height and max_height.
  3. Return the new width and height.
3. Return the innermost function.
Return the inner function.

Example

If our new_resizer function returns a set_min_size function, and set_min_size returns a resize_image function, we would use it like this:

from collections.abc import Callable

ResizeFunc = Callable[[int, int], tuple[int, int]]
SetMinSizeFunc = Callable[..., ResizeFunc]

# Step 1: Create the resizer with maximum dimensions
set_min_size: SetMinSizeFunc = new_resizer(800, 600)

# Step 2: Set the minimum dimensions
resize_image: ResizeFunc = set_min_size(200, 100)

# Step 3: Resize the image
new_width: int
new_height: int
new_width, new_height = resize_image(1000, 500)

# Step 4: Output the result
print(new_width, new_height)  # Output: 800, 500

# With currying syntax
print(new_resizer(800, 600)(200, 100)(1000, 500))  # Output: (800, 500)

Tip

If you have a value and an upper bound, using min(value, upper_bound) returns the value capped at the upper bound, i.e., the value will be returned as is unless it exceeds the upper bound.

value: int = 50
min(value, 100)  # returns 50

value = 120
min(value, 100)  # returns 100

The opposite works for lower bounds. Just use max instead.

value: int = 50
max(value, 0)  # returns 50

value = -2
max(value, 0)  # returns 0