# Video sample grabber usage

// Subscribe to the bitmap frame event
VideoCapture1.OnVideoFrameBitmap += OnVideoFrameBitmap;

private void OnVideoFrameBitmap(object sender, VideoFrameBitmapEventArgs e)
{
    // Process the Bitmap object
    ProcessBitmap(e.Frame);
    
    // If you've modified the bitmap and want to update the video stream
    e.UpdateData = true;
}

// Example of processing a Bitmap - adjusting brightness
private void ProcessBitmap(Bitmap bitmap)
{
    // Use Bitmap methods or Graphics to manipulate the image
    // This example uses ColorMatrix for brightness adjustment
    
    // Create a graphics object from the bitmap
    using (Graphics g = Graphics.FromImage(bitmap))
    {
        // Create a color matrix for brightness adjustment
        float brightnessFactor = 1.2f; // 1.0 = no change, >1.0 = brighter, <1.0 = darker
        ColorMatrix colorMatrix = new ColorMatrix(new float[][]
        {
            new float[] {brightnessFactor, 0, 0, 0, 0},
            new float[] {0, brightnessFactor, 0, 0, 0},
            new float[] {0, 0, brightnessFactor, 0, 0},
            new float[] {0, 0, 0, 1, 0},
            new float[] {0, 0, 0, 0, 1}
        });
        
        // Create an ImageAttributes object and set the color matrix
        using (ImageAttributes attributes = new ImageAttributes())
        {
            attributes.SetColorMatrix(colorMatrix);
            
            // Draw the image with the brightness adjustment
            g.DrawImage(bitmap, 
                new Rectangle(0, 0, bitmap.Width, bitmap.Height),
                0, 0, bitmap.Width, bitmap.Height,
                GraphicsUnit.Pixel, attributes);
        }
    }
}

// First, add the SkiaSharp NuGet package to your project
// Install-Package SkiaSharp

// Import necessary namespaces
using SkiaSharp;
using VisioForge.Core.MediaBlocks.VideoProcessing;
using VisioForge.Core.Types.X.Events;

// Create a VideoSampleGrabberBlock with RGBA or BGRA format
// Note: OnVideoFrameSKBitmap event works only with RGBA or BGRA formats
var videoSampleGrabberBlock = new VideoSampleGrabberBlock(VideoFormatX.BGRA);

// Enable the SaveLastFrame property if you want to take snapshots later
videoSampleGrabberBlock.SaveLastFrame = true;

// Subscribe to the SkiaSharp bitmap event
videoSampleGrabberBlock.OnVideoFrameSKBitmap += OnVideoFrameSKBitmap;

// Event handler for SkiaSharp bitmap frames
private void OnVideoFrameSKBitmap(object sender, VideoFrameSKBitmapEventArgs e)
{
    // Process the SKBitmap
    ProcessSKBitmap(e.Frame);
    
    // Note: Unlike VideoFrameBitmapEventArgs, VideoFrameSKBitmapEventArgs does not have
    // an UpdateData property as it's designed for frame viewing/analysis only
}

// Example of processing an SKBitmap - adjusting brightness
private void ProcessSKBitmap(SKBitmap bitmap)
{
    // Create a new bitmap to hold the processed image
    using (var surface = SKSurface.Create(new SKImageInfo(bitmap.Width, bitmap.Height)))
    {
        var canvas = surface.Canvas;
        
        // Set up a paint with a color filter for brightness adjustment
        using (var paint = new SKPaint())
        {
            // Create a brightness filter (1.2 = 20% brighter)
            float brightnessFactor = 1.2f;
            var colorMatrix = new float[]
            {
                brightnessFactor, 0, 0, 0, 0,
                0, brightnessFactor, 0, 0, 0,
                0, 0, brightnessFactor, 0, 0,
                0, 0, 0, 1, 0
            };
            
            paint.ColorFilter = SKColorFilter.CreateColorMatrix(colorMatrix);
            
            // Draw the original bitmap with the brightness filter applied
            canvas.DrawBitmap(bitmap, 0, 0, paint);
            
            // If you need to get the result as a new SKBitmap:
            var processedImage = surface.Snapshot();
            using (var processedBitmap = SKBitmap.FromImage(processedImage))
            {
                // Use processedBitmap for further operations or display
                // For example, display it in a SkiaSharp view
                // mySkiaView.SKBitmap = processedBitmap.Copy();
            }
        }
    }
}

// Create a method to capture and save a snapshot
private void CaptureSnapshot(string filePath)
{
    // Make sure SaveLastFrame was enabled on the VideoSampleGrabberBlock
    if (videoSampleGrabberBlock.SaveLastFrame)
    {
        // Get the last frame as an SKBitmap
        using (var bitmap = videoSampleGrabberBlock.GetLastFrameAsSKBitmap())
        {
            if (bitmap != null)
            {
                // Save the bitmap to a file
                using (var image = SKImage.FromBitmap(bitmap))
                using (var data = image.Encode(SKEncodedImageFormat.Png, 100))
                using (var stream = File.OpenWrite(filePath))
                {
                    data.SaveTo(stream);
                }
            }
        }
    }
}