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Shocking Stickers

Extra credit: Feb 04, 23:59 PM Due: Feb 11, 23:59 PM

Checking Out the Code

From your CS 225 git directory, run the following on EWS:

git fetch release
git merge release/mp_stickers -m "Merging initial mp_stickers files"

If you’re on your own machine, you may need to run:

git fetch release
git merge --allow-unrelated-histories release/mp_stickers -m "Merging initial mp_stickers files"

Upon a successful merge, your mp_stickers files are now in your mp_stickers directory.

Part 1 (Curated): The Image Class

An Image object is a subclass of the PNG class. This means it inherits all the member functions of the PNG class; so anything you could do with a PNG, you can also do with an Image.

After creating the Image class, implement the methods of the Image class:


When you’ve finished this part, you can make and run Part 1 by running:

make testimage

If execution goes smoothly, images named lighten.png, saturate.png, and scale2x.png will be created in your working directory.

  • The files expected-lighten.png and expected-saturate.png are provided and can be diffed with your output.
  • The file expected-scale2x.png is somewhat misnamed, as there are many correct solutions when you scale an image. It is not necessary to have it diff to the same image. So long as your scaling algorithm creates a reasonable scale of the original image, our autograder will see it as a reasonable scaling of the image. You can verify this by running the automated tests on Part 1.

Automated Testing

To test your code using Catch, run the following:

make test

Extra Credit Submission

For a few bonus points, you can submit the code you have implemented and tested for part one of mp_stickers. You must submit your work before the extra credit deadline (given above). Although this is optional, we encourage everyone to do this for a couple reasons:

  • if you get a sufficient grade on the submission, you will receive bonus points to improve your grade.
  • regardless of the quality of your work, you will get feedback that can be used to improve your grade on the required submission of mp_stickers.

Be sure to commit and push your work before the extra credit deadline to earn extra credit.

Part 2 (Curated): The StickerSheet Class

Lets add stickers on top of an image!

Your goal in this part of the MP is to make a StickerSheet composed of a collection of Images. To do so, you will create a class StickerSheet that will maintain an array of pointers to Image objects. Each Image in the Scene will have an index, an -coordinate, and a -coordinate. The member functions described below will support creating, modifying, and drawing the collection of Image stickers in the StickerSheet.

To implement the StickerSheet class, you will write a header file that contains a declaration of the StickerSheet class (StickerSheet.h) and a source file that contains the implementation of the StickerSheet class (StickerSheet.cpp).

To see all the required functions, check out the Doxygen:

Part 3 (Creative): Create an image with stickers!

For the last part of this MP, in the main function in main.cpp create a StickerSheet that contains an image and at least three stickers. Before exiting main, save your creation to disk as myImage.png.

We’ll take a look at your photo filled of stickers! Keep it clean and something you’re okay being shared with the class so we can show the best ones off to the whole class! :)

To generate your creative StickerSheet, you can use the following commands.


Sharing Your StickerSheet

You just made something awesome that never existed before -- you should share your art (but do not have to)!

If you share your art on Facebook, Twitter, or Instagram with #cs225, I will or the post as soon as I see it. I think many of your peers will too!   — Wade


When you’ve finished Part 2 and Part 3, you can make the full MP by running:

make test

Automated Testing

To test your code using Catch, you will need to enable the Part 2 test cases. To do so, go into tests/part2.cpp and uncomment the commented section at end of the file.

As you saw when you uncommented the test case, the test case is deliberately insufficient. We strongly recommend augmenting these tests with your own.

Once you’re ready to run the automated tests, run:

make test

Handing in your code

You must submit your work to git for grading. We will use the following files for grading:

  • Image.cpp
  • Image.h
  • StickerSheet.cpp
  • StickerSheet.h
  • main.cpp
  • myImage.png

All other flies (and files) will be ignored in grading.