Sharpen (older version)

"""
File: sharpen.py
Project 7.10

Defines and tests a function to sharpen an image.
"""

from images import Image

def sharpen(image, degree, threshold):
    """Builds and returns a sharpened image.  Expects an image
    and two integers (the degree to which the image should be sharpened and the
    threshold used to detect edges) as arguments."""

    def getDiff(colorVal1, colorVal2):
        """This auxiliary function calculates the difference between
        two tuples."""
        (r1, g1, b1) = colorVal1
        (r2, g2, b2) = colorVal2

        average1 = (r1 + g1 + b1) // 3
        average2 = (r2 + g2 + b2) // 3

        difference = average1 - average2

        return difference

    imageCopy = image.clone()            # Get a copy of the original image
    height = imageCopy.getHeight()       # Get image height
    width = imageCopy.getWidth()         # Get image width

    # Step through the pixels in the function to detect the edges
    for y in range(height -1):
        for x in range(1, width):
            (r, g, b) = imageCopy.getPixel(x, y)   # Get the color of the current pixel
            (rBottom, gBottom, bBottom) = image.getPixel(x, y + 1) # Get the color of the pixel underneath current
            (rLeft, gLeft, bLeft) = image.getPixel(x - 1, y)       # Get the color of the pixel next to current

            # Compare the current pixel with the one underneath it.
            if abs(getDiff((r, g, b), (rBottom, gBottom, bBottom))) > threshold:
                tempColor = [r + degree, g + degree, b + degree]  # Use a list to hold temporary colors, increased by degree
                bottom = [r - degree, g - degree, b - degree]     # Degree is subtracted here, to increase contrast

                # Use a loop to check for out-of range colors:
                for index in range(len(tempColor)):
                    if tempColor[index] > 255:
                        tempColor[index] = 255
                    if bottom[index] < 0:
                        bottom[index] = 0
                    tempColor[index] = tempColor[index] - bottom[index]

                # Set the new color for the pixels
                imageCopy.setPixel(x, y, tuple(tempColor))

            # Compare the current pixel with the one to its left
            elif abs(getDiff((r, g, b), (rLeft, gLeft, gLeft))) > threshold:
                tempColor = [r + degree, g + degree, b + degree]
                left = [r - degree, g - degree, b - degree]

                # Check for out-of-range colors
                for index in range(len(tempColor)):
                    if tempColor[index] > 255:
                        tempColor[index] = 255
                    if left[index] < 0:
                        left[index] = 0
                    tempColor[index] = tempColor[index] - left[index]


                # Set the new color
                imageCopy.setPixel(x, y, tuple(tempColor))

    return imageCopy


def main():
    filename = input("Enter the image file name: ")
    image = Image(filename)
    newimage = sharpen(image, 20, 15)
    newimage.draw()

if __name__ == "__main__":
   main()