HW 7 (Images Part 1)

Similar to what we did in the images lab in class, in this lab you will practice image manipulation.

Mount the COURSES drive and create a folder called hw7 in your STUWORK folder. Open the new folder in VSCode. If you need a refresher on how to complete these steps, refer back to the in-class lab from the first day of class.

Download the starter code and move the files (images.py, cImage.py, and the test images) into your hw7 folder.

If you are working on your own computer, you may need to install the Python package pillow. To do so, run the following command from the terminal:

pip3 install pillow

If that doesn't work, you can try pip install pillow instead. If that still doesn't work, reach out for help, and in the meantime, work on the lab computers.

For this part, you'll write a filter that converts an image to sepia tones, as illustated by the following image:

You should write a function sepiaFilter that takes one parameter (an Image object) and returns a new Image object. Within the sepiaFilter function, you should create a copy of the original image and then edit its pixels as follows, assuming that a given pixel has original RGB values of (redOrig, greenOrig, blueOrig):

• New red color: Use the formula redNew = redOrig * 0.39 + greenOrig * 0.77 + blueOrig * 0.19
• New green color: Use the formula greenNew = redOrig * 0.35 + greenOrig * 0.69 + blueOrig * 0.17
• New blue color: Use the formula blueNew = redOrig * 0.27 + greenOrig * 0.53 + blueOrig * 0.13

Remember that pixel RGB values must be integers. Additionally, these equations might give you pixel values that are larger than 255. In that case, you should use 255.

After writing sepiaFilter, you can test it by calling the function testFilter(imageFilename, sepiaFilter), similar to what we did for the functions we wrote in the in-class lab.

Sometimes it's nice to add a border to an image, e.g., as in this image:

For this part, you'll write a function addBorder. This function should take 3 parameters: an Image object, a border width (integer), and a border color (tuple of 3 integers). The function should return a new Image object that is a copy of the original Image object with an added border.

For example, if I use 10 as the border width parameter, I will add rows of 10 pixels to the top and the bottom of the image, and columns of 10 pixels to the sides of the image. In total, if my original image dimensions were m rows and n columns, the new image should have dimension (m + 2 * border width) times (n + 2 * border width). In other words, the border gets added around the image, do not cover up or replace pixels from the original image.

The border color will be a tuple. For example, (255, 0, 0) would correspond to adding a red border.

After you finish writing addBorder you can call display the image by calling displayImage(imgWithBorder) where imgWithBorder is the image that you returned from addBorder.

When you're finished, make sure to complete the usual documentation steps. This includes adding comments, writing function docstrings, and adding a top-level comment, acknowledgements, and a reflection to the header.

You should also think about coding style. Have you written everything in a consistent way that is easy to read? Does your code have any unnecessary print statements? (Remove them.) Is there any repetitive code that could be rewritten to use loops or helper functions? Review the style document on Moodle for the expectations for this assignment.