I have an instance of a System.Drawing.Bitmap and would like to make it available to my WPF app in the form of a System.Windows.Media.Imaging.BitmapImage.
What would be the best approach for this?
How about loading it from MemoryStream?
using(MemoryStream memory = new MemoryStream()) { bitmap.Save(memory, ImageFormat.Png); memory.Position = 0; BitmapImage bitmapImage = new BitmapImage(); bitmapImage.BeginInit(); bitmapImage.StreamSource = memory; bitmapImage.CacheOption = BitmapCacheOption.OnLoad; bitmapImage.EndInit(); } ms.Seek(0, SeekOrigin.Begin); before setting bi.StreamSource. I'm using .NET 4.0.Thanks to Hallgrim, here is the code I ended up with:
ScreenCapture = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap( bmp.GetHbitmap(), IntPtr.Zero, System.Windows.Int32Rect.Empty, BitmapSizeOptions.FromWidthAndHeight(width, height)); I also ended up binding to a BitmapSource instead of a BitmapImage as in my original question
DeleteObject on that handle.BitmapSizeOptions.FromEmptyOptions(), and it works just fine to my situation.I know this has been answered, but here are a couple of extension methods (for .NET 3.0+) that do the conversion. :)
/// <summary> /// Converts a <see cref="System.Drawing.Image"/> into a WPF <see cref="BitmapSource"/>. /// </summary> /// <param name="source">The source image.</param> /// <returns>A BitmapSource</returns> public static BitmapSource ToBitmapSource(this System.Drawing.Image source) { System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(source); var bitSrc = bitmap.ToBitmapSource(); bitmap.Dispose(); bitmap = null; return bitSrc; } /// <summary> /// Converts a <see cref="System.Drawing.Bitmap"/> into a WPF <see cref="BitmapSource"/>. /// </summary> /// <remarks>Uses GDI to do the conversion. Hence the call to the marshalled DeleteObject. /// </remarks> /// <param name="source">The source bitmap.</param> /// <returns>A BitmapSource</returns> public static BitmapSource ToBitmapSource(this System.Drawing.Bitmap source) { BitmapSource bitSrc = null; var hBitmap = source.GetHbitmap(); try { bitSrc = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap( hBitmap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions()); } catch (Win32Exception) { bitSrc = null; } finally { NativeMethods.DeleteObject(hBitmap); } return bitSrc; } and the NativeMethods class (to appease FxCop)
/// <summary> /// FxCop requires all Marshalled functions to be in a class called NativeMethods. /// </summary> internal static class NativeMethods { [DllImport("gdi32.dll")] [return: MarshalAs(UnmanagedType.Bool)] internal static extern bool DeleteObject(IntPtr hObject); } It took me some time to get the conversion working both ways, so here are the two extension methods I came up with:
using System.Drawing; using System.Drawing.Imaging; using System.IO; using System.Windows.Media.Imaging; public static Bitmap ToWinFormsBitmap(BitmapSource bitmapsource) { using (MemoryStream stream = new MemoryStream()) { BitmapEncoder enc = new PngBitmapEncoder(); enc.Frames.Add(BitmapFrame.Create(bitmapsource)); enc.Save(stream); using (var tempBitmap = new Bitmap(stream)) { // According to MSDN, one "must keep the stream open for the lifetime of the Bitmap." // So we return a copy of the new bitmap, allowing us to dispose both the bitmap and the stream. return new Bitmap(tempBitmap); } } } public static BitmapSource ToWpfBitmap(Bitmap bitmap) { using (MemoryStream stream = new MemoryStream()) { bitmap.Save(stream, ImageFormat.Png); stream.Position = 0; BitmapImage result = new BitmapImage(); result.BeginInit(); // According to MSDN, "The default OnDemand cache option retains access to the stream until the image is needed." // Force the bitmap to load right now so we can dispose the stream. result.CacheOption = BitmapCacheOption.OnLoad; result.StreamSource = stream; result.EndInit(); result.Freeze(); return result; } } BmpBitmapEncoder should be PngBitmapEncoder if you want transparency. Otherwise you get black.// at class level; [System.Runtime.InteropServices.DllImport("gdi32.dll")] public static extern bool DeleteObject(IntPtr hObject); // https://stackoverflow.com/a/1546121/194717 /// <summary> /// Converts a <see cref="System.Drawing.Bitmap"/> into a WPF <see cref="BitmapSource"/>. /// </summary> /// <remarks>Uses GDI to do the conversion. Hence the call to the marshalled DeleteObject. /// </remarks> /// <param name="source">The source bitmap.</param> /// <returns>A BitmapSource</returns> public static System.Windows.Media.Imaging.BitmapSource ToBitmapSource(this System.Drawing.Bitmap source) { var hBitmap = source.GetHbitmap(); var result = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, System.Windows.Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions()); DeleteObject(hBitmap); return result; } You can just share the pixeldata between a both namespaces ( Media and Drawing) by writing a custom bitmapsource. The conversion will happen immediately and no additional memory will be allocated. If you do not want to explicitly create a copy of your Bitmap this is the method you want.
class SharedBitmapSource : BitmapSource, IDisposable { #region Public Properties /// <summary> /// I made it public so u can reuse it and get the best our of both namespaces /// </summary> public Bitmap Bitmap { get; private set; } public override double DpiX { get { return Bitmap.HorizontalResolution; } } public override double DpiY { get { return Bitmap.VerticalResolution; } } public override int PixelHeight { get { return Bitmap.Height; } } public override int PixelWidth { get { return Bitmap.Width; } } public override System.Windows.Media.PixelFormat Format { get { return ConvertPixelFormat(Bitmap.PixelFormat); } } public override BitmapPalette Palette { get { return null; } } #endregion #region Constructor/Destructor public SharedBitmapSource(int width, int height,System.Drawing.Imaging.PixelFormat sourceFormat) :this(new Bitmap(width,height, sourceFormat) ) { } public SharedBitmapSource(Bitmap bitmap) { Bitmap = bitmap; } // Use C# destructor syntax for finalization code. ~SharedBitmapSource() { // Simply call Dispose(false). Dispose(false); } #endregion #region Overrides public override void CopyPixels(Int32Rect sourceRect, Array pixels, int stride, int offset) { BitmapData sourceData = Bitmap.LockBits( new Rectangle(sourceRect.X, sourceRect.Y, sourceRect.Width, sourceRect.Height), ImageLockMode.ReadOnly, Bitmap.PixelFormat); var length = sourceData.Stride * sourceData.Height; if (pixels is byte[]) { var bytes = pixels as byte[]; Marshal.Copy(sourceData.Scan0, bytes, 0, length); } Bitmap.UnlockBits(sourceData); } protected override Freezable CreateInstanceCore() { return (Freezable)Activator.CreateInstance(GetType()); } #endregion #region Public Methods public BitmapSource Resize(int newWidth, int newHeight) { Image newImage = new Bitmap(newWidth, newHeight); using (Graphics graphicsHandle = Graphics.FromImage(newImage)) { graphicsHandle.InterpolationMode = InterpolationMode.HighQualityBicubic; graphicsHandle.DrawImage(Bitmap, 0, 0, newWidth, newHeight); } return new SharedBitmapSource(newImage as Bitmap); } public new BitmapSource Clone() { return new SharedBitmapSource(new Bitmap(Bitmap)); } //Implement IDisposable. public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } #endregion #region Protected/Private Methods private static System.Windows.Media.PixelFormat ConvertPixelFormat(System.Drawing.Imaging.PixelFormat sourceFormat) { switch (sourceFormat) { case System.Drawing.Imaging.PixelFormat.Format24bppRgb: return PixelFormats.Bgr24; case System.Drawing.Imaging.PixelFormat.Format32bppArgb: return PixelFormats.Pbgra32; case System.Drawing.Imaging.PixelFormat.Format32bppRgb: return PixelFormats.Bgr32; } return new System.Windows.Media.PixelFormat(); } private bool _disposed = false; protected virtual void Dispose(bool disposing) { if (!_disposed) { if (disposing) { // Free other state (managed objects). } // Free your own state (unmanaged objects). // Set large fields to null. _disposed = true; } } #endregion } I work at an imaging vendor and wrote an adapter for WPF to our image format which is similar to a System.Drawing.Bitmap.
I wrote this KB to explain it to our customers:
http://www.atalasoft.com/kb/article.aspx?id=10156
And there is code there that does it. You need to replace AtalaImage with Bitmap and do the equivalent thing that we are doing -- it should be pretty straightforward.
My take on this built from a number of resources. https://stackoverflow.com/a/7035036 https://stackoverflow.com/a/1470182/360211
using System; using System.Drawing; using System.Runtime.ConstrainedExecution; using System.Runtime.InteropServices; using System.Security; using System.Windows; using System.Windows.Interop; using System.Windows.Media.Imaging; using Microsoft.Win32.SafeHandles; namespace WpfHelpers { public static class BitmapToBitmapSource { public static BitmapSource ToBitmapSource(this Bitmap source) { using (var handle = new SafeHBitmapHandle(source)) { return Imaging.CreateBitmapSourceFromHBitmap(handle.DangerousGetHandle(), IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions()); } } [DllImport("gdi32")] private static extern int DeleteObject(IntPtr o); private sealed class SafeHBitmapHandle : SafeHandleZeroOrMinusOneIsInvalid { [SecurityCritical] public SafeHBitmapHandle(Bitmap bitmap) : base(true) { SetHandle(bitmap.GetHbitmap()); } [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)] protected override bool ReleaseHandle() { return DeleteObject(handle) > 0; } } } } I came to this question because I was trying to do the same, but in my case the Bitmap is from a resource/file. I found the best solution is as described in the following link:
http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.bitmapimage.aspx
// Create the image element. Image simpleImage = new Image(); simpleImage.Width = 200; simpleImage.Margin = new Thickness(5); // Create source. BitmapImage bi = new BitmapImage(); // BitmapImage.UriSource must be in a BeginInit/EndInit block. bi.BeginInit(); bi.UriSource = new Uri(@"/sampleImages/cherries_larger.jpg",UriKind.RelativeOrAbsolute); bi.EndInit(); // Set the image source. simpleImage.Source = bi;