ARTICLE AD BOX
I have a loop that receives image data as a Bitmap object that I need to manipulate quickly in order to process the next frame.
Consider the following code:
private static void Main () { var opacity = (byte) 127; var channelAlpha = (int) 3; var pixelFormat = PixelFormat.Format32bppArgb; var boundsSource = Screen.PrimaryScreen!.Bounds; var copyPixelOperation = CopyPixelOperation.SourceCopy; var boundsTarget = new Rectangle (x: 0, y: 0, width: boundsSource.Width, height: boundsSource.Height); using (var bitmap = new Bitmap (boundsSource.Width, boundsSource.Height, pixelFormat)) { using (var graphics = Graphics.FromImage (bitmap)) graphics.CopyFromScreen (boundsSource.X, boundsSource.Y, boundsTarget.X, boundsTarget.Y, boundsSource.Size, copyPixelOperation); var bitmapData = bitmap.LockBits (rect: boundsTarget, flags: ImageLockMode.ReadWrite, format: pixelFormat); var buffer = new byte [Math.Abs (bitmapData.Stride) * bitmapData.Height]; // Reduce opacity. Marshal.Copy (source: bitmapData.Scan0, destination: buffer, startIndex: 0, length: buffer.Length); for (int i = 0; i < buffer.Length; i += 4) { buffer [i + channelAlpha] = opacity; } Marshal.Copy (source: buffer, destination: bitmapData.Scan0, startIndex: 0, length: buffer.Length); bitmap.UnlockBits (bitmapData); } }I would like to know if there is some way to avoid making a copy of the image buffer in order to manipulate it. I know that I could use unsafe code to cast bitmapData.Scan0 to to any kind of a pointer. My question is, is it possible to use Span<T> or Memory<T> while avoiding Marshall.Copy and unsafe code altogether?
