WPF CreateBitmapSourceFromHBitmap() memory leak
MSDN for Bitmap.GetHbitmap()
states:
Remarks
You are responsible for calling the GDI DeleteObject method to free the memory used by the GDI bitmap object.
So use the following code:
// at class level[System.Runtime.InteropServices.DllImport("gdi32.dll")]public static extern bool DeleteObject(IntPtr hObject);// your codeusing (System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(1000, 1000)) { IntPtr hBitmap = bmp.GetHbitmap(); try { var source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions()); } finally { DeleteObject(hBitmap); }}
I also replaced your Dispose()
call by an using
statement.
Whenever dealing with unmanaged handles it can be a good idea to use the "safe handle" wrappers:
public class SafeHBitmapHandle : SafeHandleZeroOrMinusOneIsInvalid{ [SecurityCritical] public SafeHBitmapHandle(IntPtr preexistingHandle, bool ownsHandle) : base(ownsHandle) { SetHandle(preexistingHandle); } protected override bool ReleaseHandle() { return GdiNative.DeleteObject(handle) > 0; }}
Construct one like so as soon as you surface a handle (ideally your APIs would never expose IntPtr, they would always return safe handles):
IntPtr hbitmap = bitmap.GetHbitmap();var handle = new SafeHBitmapHandle(hbitmap , true);
And use it like so:
using (handle){ ... Imaging.CreateBitmapSourceFromHBitmap(handle.DangerousGetHandle(), ...)}
The SafeHandle base gives you an automatic disposable/finalizer pattern, all you need to do is override the ReleaseHandle method.
I had the same requirement and issue (memory leak). I implemented the same solution as marked as answer. But although the solution works, it caused an unacceptable hit to performance. Running on a i7, my test app saw a steady 30-40% CPU, 200-400MB RAM increases and the garbage collector was running almost every millisecond.
Since I'm doing video processing, I'm in need of much better performance. I came up with the following, so thought I would share.
Reusable Global Objects
//set up your Bitmap and WritableBitmap as you see fitBitmap colorBitmap = new Bitmap(..);WriteableBitmap colorWB = new WriteableBitmap(..);//choose appropriate bytes as per your pixel format, I'll cheat here an just pick 4int bytesPerPixel = 4;//rectangles will be used to identify what bits changeRectangle colorBitmapRectangle = new Rectangle(0, 0, colorBitmap.Width, colorBitmap.Height);Int32Rect colorBitmapInt32Rect = new Int32Rect(0, 0, colorWB.PixelWidth, colorWB.PixelHeight);
Conversion Code
private void ConvertBitmapToWritableBitmap(){ BitmapData data = colorBitmap.LockBits(colorBitmapRectangle, ImageLockMode.WriteOnly, colorBitmap.PixelFormat); colorWB.WritePixels(colorBitmapInt32Rect, data.Scan0, data.Width * data.Height * bytesPerPixel, data.Stride); colorBitmap.UnlockBits(data); }
Implementation Example
//do stuff to your bitmapConvertBitmapToWritableBitmap();Image.Source = colorWB;
The result is a steady 10-13% CPU, 70-150MB RAM, and the garbage collector only ran twice in a 6 minute run.