Midge Major Image Effect Generator

function processImage(originalImg, midgeIntensity = "50", contrastLevel = "1.2", tintColor = "#ffb347") {
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d');
    
    const width = originalImg.width;
    const height = originalImg.height;
    canvas.width = width;
    canvas.height = height;

    // Draw the original image onto the canvas
    ctx.drawImage(originalImg, 0, 0);
    const imgData = ctx.getImageData(0, 0, width, height);
    const data = imgData.data;

    // Parse parameters
    const noiseLevel = parseFloat(midgeIntensity) || 50;
    const contrast = parseFloat(contrastLevel) || 1.2;
    
    // Parse tint color safely
    let tr = 255, tg = 179, tb = 71;
    let hex = String(tintColor).trim().replace(/^#/, '');
    if (hex.length === 3) {
        hex = hex.split('').map(x => x + x).join('');
    }
    if (hex.length === 6) {
        tr = parseInt(hex.substring(0, 2), 16);
        tg = parseInt(hex.substring(2, 4), 16);
        tb = parseInt(hex.substring(4, 6), 16);
    }
    if (isNaN(tr) || isNaN(tg) || isNaN(tb)) {
        tr = 255; tg = 179; tb = 71; // default to a warm vintage tint
    }

    const intercept = 128 * (1 - contrast);

    // Apply the Midge Major effect at the pixel level
    for (let i = 0; i < data.length; i += 4) {
        let r = data[i];
        let g = data[i + 1];
        let b = data[i + 2];

        // 1. Contrast Boost
        r = r * contrast + intercept;
        g = g * contrast + intercept;
        b = b * contrast + intercept;

        // 2. Multiply Tint
        r = (r * tr) / 255;
        g = (g * tg) / 255;
        b = (b * tb) / 255;

        // 3. "Midge" Noise Synthesis
        // Produces a crawling gritty effect across the image
        const noise = (Math.random() - 0.5) * noiseLevel;
        r += noise;
        g += noise;
        b += noise;

        // Clamp values
        data[i] = Math.max(0, Math.min(255, r));
        data[i + 1] = Math.max(0, Math.min(255, g));
        data[i + 2] = Math.max(0, Math.min(255, b));
        // Alpha (data[i + 3]) is left untouched
    }

    ctx.putImageData(imgData, 0, 0);

    // 4. "Major" Vignette Overlay
    // Gives the final output a deep cinematic focal pull
    const cx = width / 2;
    const cy = height / 2;
    const radius = Math.max(width, height) / 1.5;
    
    const gradient = ctx.createRadialGradient(cx, cy, radius * 0.3, cx, cy, radius);
    gradient.addColorStop(0, 'rgba(0, 0, 0, 0)');
    gradient.addColorStop(1, 'rgba(15, 15, 20, 0.7)');
    
    ctx.globalCompositeOperation = 'multiply';
    ctx.fillStyle = gradient;
    ctx.fillRect(0, 0, width, height);

    // Reset composite operation
    ctx.globalCompositeOperation = 'source-over';

    return canvas;
}