How to capture a control to bitmap?

Question

I want to make a paint project with my mouse and capture it to bitmap

how to do it?

save a control to bitmap?

i am using windows sdk winui3

Answer 1

Use RenderTargetBitmap

For example, a test with a Button saved to a .PNG image =>

            Microsoft.UI.Xaml.Media.Imaging.RenderTargetBitmap renderTargetBitmap = new Microsoft.UI.Xaml.Media.Imaging.RenderTargetBitmap();  
            await renderTargetBitmap.RenderAsync(myButton);  
            var pixelBuffer = await renderTargetBitmap.GetPixelsAsync();   

            Windows.Storage.StorageFolder folder = await Windows.Storage.StorageFolder.GetFolderFromPathAsync(@"E:\");       
            var destfile = await folder.CreateFileAsync("controlimage.png", Windows.Storage.CreationCollisionOption.ReplaceExisting);  
            using (var ras = await destfile.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite, Windows.Storage.StorageOpenOptions.None))  
            {                     
                Windows.Graphics.Imaging.BitmapEncoder encoder = await Windows.Graphics.Imaging.BitmapEncoder.CreateAsync(Windows.Graphics.Imaging.BitmapEncoder.PngEncoderId, ras);  
                encoder.SetPixelData(Windows.Graphics.Imaging.BitmapPixelFormat.Bgra8, Windows.Graphics.Imaging.BitmapAlphaMode.Straight, (uint)renderTargetBitmap.PixelWidth, (uint)renderTargetBitmap.PixelHeight, 96.0, 96.0, pixelBuffer.ToArray());  
                await encoder.FlushAsync();  
            }