Image D.J. Russ Effect Generator

function processImage(originalImg, intensity = 100, noiseLevel = 20, addScanlines = 1) {
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d');

    // Set canvas dimensions to match the original image
    canvas.width = originalImg.width;
    canvas.height = originalImg.height;
    
    // Draw the original image onto the canvas
    ctx.drawImage(originalImg, 0, 0);

    // Fetch the raw pixel data
    const imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
    const data = imgData.data;

    // Parse parameters
    const amt = Math.max(0, Math.min(100, Number(intensity))) / 100;
    const noise = Number(noiseLevel);
    const drawScan = Number(addScanlines);

    // Calculate contrast factor (High contrast up to 100 for the creepy effect)
    const contrast = 100 * amt;
    const factor = (259 * (contrast + 255)) / (255 * (259 - contrast));

    // Process each pixel
    for (let i = 0; i < data.length; i += 4) {
        let r = data[i];
        let g = data[i + 1];
        let b = data[i + 2];

        // 1. Apply Contrast
        let rc = factor * (r - 128) + 128;
        let gc = factor * (g - 128) + 128;
        let bc = factor * (b - 128) + 128;

        // Clamp to 0-255 range after contrast
        rc = Math.min(255, Math.max(0, rc));
        gc = Math.min(255, Math.max(0, gc));
        bc = Math.min(255, Math.max(0, bc));

        // 2. X.exe / D.J. Russ Effect (Inverted colors + aggressive deep-fry red tint)
        // White becomes black (void), Black becomes dark bloody red. 
        let r_inv = 255 - rc;
        let g_inv = 255 - gc;
        let b_inv = 255 - bc;

        let r_new = r_inv * 1.5;  // Boost red channel heavily
        let g_new = g_inv * 0.4;  // Suppress green
        let b_new = b_inv * 0.4;  // Suppress blue

        // 3. Apply random static/noise to enhance the "cursed" look
        if (noise > 0) {
            const noiseVal = (Math.random() - 0.5) * noise * 2 * amt;
            r_new += noiseVal;
            g_new += noiseVal;
            b_new += noiseVal;
        }

        // 4. Blend the new X.exe effect with the original image based on intensity percentage
        data[i]     = Math.min(255, Math.max(0, r + (r_new - r) * amt));
        data[i + 1] = Math.min(255, Math.max(0, g + (g_new - g) * amt));
        data[i + 2] = Math.min(255, Math.max(0, b + (b_new - b) * amt));
        // Keeping alpha (data[i + 3]) untouched
    }

    // Put modified data back to the canvas
    ctx.putImageData(imgData, 0, 0);

    // 5. Optionally draw digital scanlines over the canvas
    if (drawScan > 0 && amt > 0) {
        ctx.fillStyle = `rgba(0, 0, 0, ${0.3 * amt})`;
        for (let y = 0; y < canvas.height; y += 3) {
            ctx.fillRect(0, y, canvas.width, 1);
        }
    }

    return canvas;
}