Photo To HIFI VHSRip 16mm Effects Converter

function processImage(originalImg, intensity = 50, colorShiftAmount = 3, noiseAmount = 25, enableText = 1) {
    const canvas = document.createElement('canvas');
    const width = originalImg.width;
    const height = originalImg.height;
    canvas.width = width;
    canvas.height = height;
    const ctx = canvas.getContext('2d');

    // Draw original image
    ctx.drawImage(originalImg, 0, 0);

    // Grab pixel data for manipulation
    const imageData = ctx.getImageData(0, 0, width, height);
    const data = imageData.data;
    const outData = new Uint8ClampedArray(data);

    // Calculate dynamic effect scales based on image size
    const shift = Math.max(1, Math.floor((width / 1000) * colorShiftAmount * (intensity / 50)));
    
    // Contrast adjustment factor (adds that crunchy VHS look)
    const contrast = 20 * (intensity / 50);
    const contrastFactor = (259 * (contrast + 255)) / (255 * (259 - contrast));

    // Pixel processing loop
    for (let y = 0; y < height; y++) {
        let jitter = 0;
        
        // Define bottom tracking line error (VHS characteristic)
        const isTrackingBand = (y > height * 0.90 && y < height * 0.95);

        // Apply horizontal jitter
        if (isTrackingBand) {
            jitter = Math.floor((Math.random() - 0.5) * (width / 50) * (intensity / 50));
        } else if (Math.random() < 0.03) {
            // Random jitter for standard scanlines
            jitter = Math.floor((Math.random() - 0.5) * (width / 200) * (intensity / 50));
        }

        for (let x = 0; x < width; x++) {
            const i = (y * width + x) * 4;

            // Chromatic aberration / Red-Blue shift
            let rX = Math.max(0, Math.min(width - 1, x - shift + jitter));
            let gX = Math.max(0, Math.min(width - 1, x + jitter));
            let bX = Math.max(0, Math.min(width - 1, x + shift + jitter));

            const iR = (y * width + rX) * 4;
            const iG = (y * width + gX) * 4;
            const iB = (y * width + bX) * 4;

            let r = data[iR];
            let g = data[iG + 1];
            let b = data[iB + 2];

            // Specific VHS Tracking static (speckles)
            if (isTrackingBand && Math.random() < 0.15) {
                r = g = b = 180 + Math.random() * 75;
            }

            // Apply contrast
            r = contrastFactor * (r - 128) + 128;
            g = contrastFactor * (g - 128) + 128;
            b = contrastFactor * (b - 128) + 128;

            // 16mm Color Grading (Slight warmth + green shadows typically seen in analog transfers)
            r += 10;
            g += 2;
            b -= 5;

            // Apply Film Grain / Noise
            const noise = (Math.random() - 0.5) * (noiseAmount * 2) * (intensity / 50);

            outData[i] = r + noise;
            outData[i + 1] = g + noise;
            outData[i + 2] = b + noise;
            outData[i + 3] = 255; // Alpha
        }
    }

    // Write processed pixels back
    imageData.data.set(outData);
    ctx.putImageData(imageData, 0, 0);

    // Apply Overlays
    
    // 1. Scanlines (VHS)
    const scanlineHeight = Math.max(1, Math.floor(height / 400));
    ctx.fillStyle = `rgba(0, 0, 0, 0.15)`;
    for (let i = 0; i < height; i += scanlineHeight * 2) {
        ctx.fillRect(0, i, width, scanlineHeight);
    }

    // 2. Vignette (16mm Film effect)
    ctx.globalCompositeOperation = 'multiply';
    const cx = width / 2;
    const cy = height / 2;
    const radius = Math.max(cx, cy);
    const gradient = ctx.createRadialGradient(cx, cy, radius * 0.4, cx, cy, radius * 1.1);
    gradient.addColorStop(0, 'rgba(0, 0, 0, 0)');
    gradient.addColorStop(1, 'rgba(0, 0, 0, 0.7)');
    ctx.fillStyle = gradient;
    ctx.fillRect(0, 0, width, height);
    ctx.globalCompositeOperation = 'source-over';

    // 3. Vertical Film Scratches (16mm Film effect)
    for (let i = 0; i < 5; i++) {
        let sX = Math.random() * width;
        // White scratch
        ctx.beginPath();
        ctx.moveTo(sX, 0);
        ctx.lineTo(sX + (Math.random() - 0.5) * 10, height);
        ctx.strokeStyle = `rgba(255, 255, 255, ${Math.random() * 0.15 + 0.05})`;
        ctx.lineWidth = Math.random() * 2 + 1;
        ctx.stroke();

        // Dark scratch
        sX = Math.random() * width;
        ctx.beginPath();
        ctx.moveTo(sX, 0);
        ctx.lineTo(sX + (Math.random() - 0.5) * 5, height);
        ctx.strokeStyle = `rgba(0, 0, 0, ${Math.random() * 0.2 + 0.05})`;
        ctx.lineWidth = Math.random() * 2 + 1;
        ctx.stroke();
    }

    // 4. VHS Camcorder OSD / Date Text
    if (Number(enableText) === 1) {
        const fontSize = Math.max(20, Math.floor(height * 0.05));
        ctx.font = `${fontSize}px "Courier New", Courier, monospace`;
        ctx.fillStyle = 'rgba(255, 255, 255, 0.9)';
        ctx.shadowColor = 'black';
        ctx.shadowBlur = width * 0.005;
        ctx.shadowOffsetX = width * 0.002;
        ctx.shadowOffsetY = width * 0.002;
        
        // "PLAY" icon
        ctx.fillText("PLAY \u25BA", width * 0.05, height * 0.1);
        
        // Timer/Date
        ctx.fillText("OCT. 26 1985", width * 0.05, height * 0.85);
        ctx.fillText("AM 01:20:00", width * 0.05, height * 0.85 + fontSize * 1.2);
        
        // Reset shadow
        ctx.shadowColor = 'transparent';
    }

    return canvas;
}