<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Image Processing with JS</title>
</head>
<body>
  <label for="imageLink">Image Link:</label>
  <br>
  <input type="file" id="fileInput" accept="image/*">
  <br>
  <button id="loadButton" style="display: inline;">Load Image</button>
  <br>
  <canvas id="canvas" style="border: 1px solid #000;"></canvas>
  <br>
  <button id="processButton" style="display: none;">Process Image to Binary</button>
  <button id="reverseHexButton" style="display: none;">Reverse Hex Color</button>
  <button id="originalButton" style="display: none;">Show Original Image</button>

  <script>
  document.addEventListener('DOMContentLoaded', function() {
    const canvas = document.getElementById('canvas');
    const ctx = canvas.getContext('2d');
    const loadButton = document.getElementById('loadButton');
    const processButton = document.getElementById('processButton');
    const originalButton = document.getElementById('originalButton');
    const reverseHexButton = document.getElementById('reverseHexButton');
    const fileInput = document.getElementById('fileInput');
    let img = new Image();

    function clearCanvas() {
      ctx.clearRect(0, 0, canvas.width, canvas.height);
    }

    function loadAndDisplayImage() {
      const file = fileInput.files[0];

      if (!file) {
        alert('Please select a file.');
        return;
      }

      clearCanvas();

      const reader = new FileReader();
      reader.onload = function(e) {
        img.onload = function() {
          const targetWidth = 1000;
          const scaleFactor = targetWidth / img.width;
          canvas.width = targetWidth;
          canvas.height = img.height * scaleFactor;
          ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
          processButton.style.display = 'inline';
          reverseHexButton.style.display = 'inline';
          originalButton.style.display = 'none';
        };
        img.src = e.target.result;
      };
      reader.readAsDataURL(file);
    }

    function convertToBinary() {
      const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
      const data = imageData.data;
      for (let i = 0; i < data.length; i += 4) {
        const brightness = 0.34 * data[i] + 0.5 * data[i + 1] + 0.16 * data[i + 2];
        const threshold = 128;
        const color = brightness > threshold ? 255 : 0;
        data[i] = data[i + 1] = data[i + 2] = color;
      }
      ctx.putImageData(imageData, 0, 0);
      toggleButtonsAfterProcessing();
    }

    function reverseHexColor() {
      const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
      const data = imageData.data;
      for (let i = 0; i < data.length; i += 4) {
        data[i] = 255 - data[i];       // Reverse Red
        data[i + 1] = 255 - data[i + 1]; // Reverse Green
        data[i + 2] = 255 - data[i + 2]; // Reverse Blue
      }
      ctx.putImageData(imageData, 0, 0);
      toggleButtonsAfterProcessing();
    }

    function toggleButtonsAfterProcessing() {
      processButton.style.display = 'none';
      reverseHexButton.style.display = 'none';
      originalButton.style.display = 'inline';
    }

    loadButton.addEventListener('click', loadAndDisplayImage);
    processButton.addEventListener('click', convertToBinary);
    reverseHexButton.addEventListener('click', reverseHexColor);
    originalButton.addEventListener('click', () => {
      if (img.complete && img.src) {
        ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
        processButton.style.display = 'inline';
        reverseHexButton.style.display = 'inline';
        originalButton.style.display = 'none';
      }
    });
  });
</script>
</body>
</html>

Convert to Binary

The goal of this function is to convert the loaded image into a binary format. It achieves this by applying a threshold to the brightness of each pixel in the image. Here’s the breakdown:

Get Image Data

   const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);

Decide Whether Pixel is White or Black

for (let i = 0; i < data.length; i += 4) {
  const brightness = 0.34 * data[i] + 0.5 * data[i + 1] + 0.16 * data[i + 2];
  const threshold = 128;
  const color = brightness > threshold ? 255 : 0;
  data[i] = data[i + 1] = data[i + 2] = color;
}

It calculates the brightness of each pixel using a weighted sum of its RGB values. If the brightness is greater than a threshold (128), it sets the pixel color to white (255); otherwise, it sets it to black (0).

Reverse Hex Color

The purpose of this function is to reverse the hex color of each pixel in the loaded image. It achieves this by subtracting each color component from 255. Here’s the breakdown:

Get Image Data

   const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);

Reverse Hex Color

for (let i = 0; i < data.length; i += 4) {
  data[i] = 255 - data[i];        // Reverse Red
  data[i + 1] = 255 - data[i + 1]; // Reverse Green
  data[i + 2] = 255 - data[i + 2]; // Reverse Blue
}

It subtracts each color component (Red, Green, Blue) from 255, effectively creating a color negative.

If I had more time

If I had more time I would add…

A more user-interactive interface

Include some more features that display conversions of Binary Image Processing

Talk more about how the conversions work and give more details about this topic

Problems I cam across

My conversions wouldn't work many, like converting to binary or reversing the hex. I had to debug the code and look at was wrong.

Figuring the conversion between regular pixels and binary

Figuring out how to reverse the pixels. 