Creating a BitmapImage WPF

試著忘記壹切 提交于 2019-12-01 08:09:03

My previous method for converting Bitmap to BitmapImage was:

MemoryStream ms = new MemoryStream(); 
bitmap.Save(ms, ImageFormat.Png); 
ms.Position = 0; 
BitmapImage bi = new BitmapImage(); 
bi.BeginInit(); 
bi.StreamSource = ms; 
bi.EndInit();

I was able to speed it up using

Imaging.CreateBitmapSourceFromHBitmap(bitmap.GetHbitmap(), 
                                      IntPtr.Zero, 
                                      Int32Rect.Empty,
                                      System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());

EDIT: anyone using this should know that bitmap.GetHbitmap creates an unmanaged object lying around, since this is unmanaged it wont be picked up by the .net garbage collector and must be deleted to avoid a memory leak, use the following code to solve this:

    [System.Runtime.InteropServices.DllImport("gdi32.dll")]
    public static extern bool DeleteObject(IntPtr hObject);

    IntPtr hBitmap = bitmap.GetHbitmap();
    try
    {
        imageSource = Imaging.CreateBitmapSourceFromHBitmap(hBitmap,
                                                            IntPtr.Zero,
                                                            Int32Rect.Empty,
                                                            System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
    }
    catch (Exception e) { }
    finally
    {
        DeleteObject(hBitmap);
    }

(its not very neat having to import a dll like like but this was taken from msdn, and seems to be the only way around this issue - http://msdn.microsoft.com/en-us/library/1dz311e4.aspx )

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