README.md

PixSorter - Using algorithms to sort images

This web app provides a chance to explore foundational sorting algorithms in a practical context, while allowing users to view images in an unusual and interesting new way.

Tech stack

• Typescript
• Next JS
• Sass
• Framer Motion
• Jest
• React Testing Library

Deployment

Website is hosted on Vercel, and is available at pixsorter.com

How to install

1. Clone from Github

   cd projects
   git clone <repo-tag>

2. Add environment variables

   Create .env file in the root directory that includes the required variables for Unsplash API.

3. Install dependencies

   Run yarn install to install dependencies.

4. Run tests

   Run yarn test see results of unit tests.

5. Start app locally

   Run yarn start to launch the app on localhost:3000

Key site features

Sorting algorithms passed via context with shared interface

To allow for easy switching between algorithms, they share a common interface and are passed via context to the function that renders the pixel array (periodically) to the screen.

Algorithm interface

export type SortAlgoTypes = (
  array: Uint8ClampedArray,
  sortedCallback: () => void,
  compare: compareFnTypes,
  sortPosition: number | SortDataTypes | null,
  pixelIdxLength?: number,
  renderLoops?: number
) => number | SortDataTypes;

Animation function in Canvas component

const draw = useCallback(() => {
  const finishedSorting = () => {
    setIsSorted(true);
    setKeepSorting(false);
  };
  if (keepSorting && !isSorted) {
    if (imgData.current?.data && context.current) {
      // Algorithm will run for a set number of loops
      // before rendering to the screen
      let updatedPositionData = algorithm(
        imgData.current.data,
        finishedSorting,
        sortBy,
        sortPosition
      );
      setSortPosition(updatedPositionData);
      context.current.putImageData(imgData.current, 0, 0);
      requestId.current = requestAnimationFrame(draw);
    }
  }
  [...]
},[...]);

Side-scrolling selection component

The sideways selector component provides fluid user interaction through using Framer Motion's easeInOut transition animation for revealing hidden content, by and smoothly scrolling to the position of the selected value by passing down a reference to the parent container to the FieldValue component.

const FieldValue = ({
  value,
  active,
  parentRef,
}: {
  value: string;
  active: boolean;
  parentRef: RefObject<HTMLElement>;
}) => {
  const optionRef = useRef<HTMLLIElement>(null);

  useEffect(() => {
    if (active && optionRef.current && parentRef?.current) {
      parentRef.current.scrollTo({
        left: optionRef.current.offsetLeft - optionRef.current.clientWidth,
        behavior: "smooth",
      });
    }
  }, [active, parentRef]);

  return (
    <li ref={optionRef} className={styles.fieldListItem}>
      {value}
    </li>
  );
};

Challenges and Improvements

Algorithm pacing is a challenge, especially for the faster algorithms. Merge sort needs to be slowed down.

There's also more testing to be done. And a couple of other algorithms to add.

Next I'd like to implement K-means clustering to find and visualise the most common colours in an image - perhaps as a microservice that's called by the client.