Image Arctic Ice Blue Filter

function processImage(originalImg) {
    // 1. Create a canvas element
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d');

    // 2. Set canvas dimensions to the original image's dimensions
    // Ensure the image is loaded, otherwise naturalWidth/Height might be 0
    // For this problem, we assume originalImg is a fully loaded Image object
    canvas.width = originalImg.naturalWidth;
    canvas.height = originalImg.naturalHeight;

    // 3. Draw the original image onto the canvas
    ctx.drawImage(originalImg, 0, 0);

    // 4. Get the ImageData object from the canvas
    // This provides access to the raw pixel data
    const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
    const data = imageData.data; // data is a Uint8ClampedArray: [R,G,B,A, R,G,B,A, ...]

    // 5. Apply the Arctic Ice Blue filter to each pixel
    for (let i = 0; i < data.length; i += 4) {
        const r = data[i];     // Red channel
        const g = data[i + 1]; // Green channel
        const b = data[i + 2]; // Blue channel
        // data[i + 3] is the Alpha channel, we'll leave it unchanged

        // Apply "Arctic Ice Blue" transformation
        // This specific transformation aims for a cool, bright, blueish tint.
        // - Reduce red component
        // - Slightly reduce green component or adjust it to contribute to cyan
        // - Significantly boost blue component
        // - Add offsets to slightly brighten the image and enhance the "icy" feel

        let newR = r * 0.8 + 20;
        let newG = g * 0.9 + 30;
        let newB = b * 1.0 + 70; // or simply b + 70

        // The Uint8ClampedArray automatically clamps values to the 0-255 range.
        // So, direct assignment is fine.
        // Example: if newR becomes 300, data[i] will be 255. If -50, data[i] will be 0.
        data[i] = newR;
        data[i + 1] = newG;
        data[i + 2] = newB;
    }

    // 6. Put the modified pixel data back onto the canvas
    ctx.putImageData(imageData, 0, 0);

    // 7. Return the canvas element
    return canvas;
}