California Driver License Realism Enhancer

function processImage(originalImg, glareIntensity = '0.3', cornerRounding = '0.04', shadowBlurAmount = '15', grainAmount = '8') {
    const glare = parseFloat(glareIntensity);
    const radiusPercent = parseFloat(cornerRounding);
    const shadow = parseFloat(shadowBlurAmount);
    const grain = parseFloat(grainAmount);

    // Calculate dimensions with padding to accommodate the drop shadow
    const padding = shadow * 2 + 10;
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d');

    const cardWidth = originalImg.width;
    const cardHeight = originalImg.height;

    // Expand canvas beyond the original image size to allow for 3D realism effects
    canvas.width = cardWidth + padding * 2;
    canvas.height = cardHeight + padding * 2;

    // Drivers licenses and ID cards have standard rounded corners
    const radius = Math.min(cardWidth, cardHeight) * radiusPercent;

    // 1. Draw the drop shadow simulating the card sitting on a surface
    ctx.save();
    ctx.translate(padding, padding);

    ctx.shadowColor = 'rgba(0, 0, 0, 0.45)';
    ctx.shadowBlur = shadow;
    ctx.shadowOffsetX = shadow * 0.3;
    ctx.shadowOffsetY = shadow * 0.6;

    // Create the rounded corner path
    ctx.beginPath();
    ctx.moveTo(radius, 0);
    ctx.lineTo(cardWidth - radius, 0);
    ctx.quadraticCurveTo(cardWidth, 0, cardWidth, radius);
    ctx.lineTo(cardWidth, cardHeight - radius);
    ctx.quadraticCurveTo(cardWidth, cardHeight, cardWidth - radius, cardHeight);
    ctx.lineTo(radius, cardHeight);
    ctx.quadraticCurveTo(0, cardHeight, 0, cardHeight - radius);
    ctx.lineTo(0, radius);
    ctx.quadraticCurveTo(0, 0, radius, 0);
    ctx.closePath();

    // Fill to cast the shadow
    ctx.fillStyle = '#ffffff';
    ctx.fill();
    ctx.restore();

    // 2. Clip the drawing area to the card's rounded boundaries
    ctx.save();
    ctx.translate(padding, padding);
    ctx.beginPath();
    ctx.moveTo(radius, 0);
    ctx.lineTo(cardWidth - radius, 0);
    ctx.quadraticCurveTo(cardWidth, 0, cardWidth, radius);
    ctx.lineTo(cardWidth, cardHeight - radius);
    ctx.quadraticCurveTo(cardWidth, cardHeight, cardWidth - radius, cardHeight);
    ctx.lineTo(radius, cardHeight);
    ctx.quadraticCurveTo(0, cardHeight, 0, cardHeight - radius);
    ctx.lineTo(0, radius);
    ctx.quadraticCurveTo(0, 0, radius, 0);
    ctx.closePath();
    ctx.clip();

    // 3. Draw the original image with slight photographic enhancements
    ctx.filter = 'contrast(105%) saturate(110%) brightness(98%)';
    ctx.drawImage(originalImg, 0, 0, cardWidth, cardHeight);
    ctx.filter = 'none';

    // 4. Add a simulated plastic lamination glare / subtle hologram reflection
    const overlayGrad1 = ctx.createLinearGradient(0, 0, cardWidth, cardHeight);
    overlayGrad1.addColorStop(0, `rgba(255, 255, 255, ${glare})`);
    overlayGrad1.addColorStop(0.2, 'rgba(255, 255, 255, 0)');
    overlayGrad1.addColorStop(0.4, 'rgba(255, 255, 255, 0)');
    overlayGrad1.addColorStop(0.5, `rgba(255, 255, 255, ${glare * 0.4})`);
    overlayGrad1.addColorStop(0.55, 'rgba(255, 255, 255, 0)');
    overlayGrad1.addColorStop(1, 'rgba(255, 255, 255, 0)');

    ctx.globalCompositeOperation = 'screen';
    ctx.fillStyle = overlayGrad1;
    ctx.fill();

    // Secondary angled reflection to emphasize flat physical surfaces
    const overlayGrad2 = ctx.createLinearGradient(0, cardHeight, cardWidth, 0);
    overlayGrad2.addColorStop(0.3, 'rgba(255, 255, 255, 0)');
    overlayGrad2.addColorStop(0.4, `rgba(255, 255, 255, ${glare * 0.15})`);
    overlayGrad2.addColorStop(0.45, `rgba(255, 255, 255, ${glare * 0.5})`);
    overlayGrad2.addColorStop(0.5, 'rgba(255, 255, 255, 0)');
    ctx.fillStyle = overlayGrad2;
    ctx.fill();

    ctx.globalCompositeOperation = 'source-over';

    // 5. Add slight camera noise/film grain for photographic realism
    const imgData = ctx.getImageData(padding, padding, cardWidth, cardHeight);
    const data = imgData.data;
    
    for (let i = 0; i < data.length; i += 4) {
        // Generate uniform monochrome noise
        const noise = (Math.random() - 0.5) * grain;
        
        data[i] = Math.min(255, Math.max(0, data[i] + noise));     // Red
        data[i+1] = Math.min(255, Math.max(0, data[i+1] + noise)); // Green
        data[i+2] = Math.min(255, Math.max(0, data[i+2] + noise)); // Blue
    }
    
    // Put modified data back onto the canvas inside the clipped region
    ctx.putImageData(imgData, padding, padding);

    ctx.restore();

    return canvas;
}