Comment utiliser un SharpDX.WIC.Bitmap dans une application WPF?

Question

Je dois présenter un WIC Bitmap de SharpDX dans une application WPF. Le bitmap WIC hérite de BitmapSource, mais ce n'est pas le même BitmapSource que WPF utilise, bien que les noms de classe soient les mêmes. Comment puis-je convertir de l'un à l'autre?

Answer 1

Ce que vous pouvez faire est de créer une classe dérivée personnalisée à partir de BitmapSource de WPF.

Par exemple, pour ce XAML:

<Window x:Class="SharpDXWpfApp.MainWindow" 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
     Title="MainWindow" Height="350" Width="525"> 
    <Grid> 
     <Image Name="MyImage"></Image> 
    </Grid> 
</Window> 

Ce code de fenêtre utilise une coutume "WicBitmapSource".

public partial class MainWindow : Window 
{ 
    private WicBitmapSource _bmp; 

    public MainWindow() 
    { 
     InitializeComponent(); 
     _bmp = new WicBitmapSource(@"c:\path\killroy_was_here.png"); 
     MyImage.Source = _bmp; 
    } 

    protected override void OnClosed(EventArgs e) 
    { 
     _bmp.Dispose(); 
    } 
} 

Voici quelques exemples de code pour cette SharpDX/Wic BitmapSource personnalisé (certaines informations sont saisies d'ici: https://blogs.msdn.microsoft.com/dwayneneed/2008/06/20/implementing-a-custom-bitmapsource/).

public class WicBitmapSource : System.Windows.Media.Imaging.BitmapSource, IDisposable 
{ 
    public WicBitmapSource(string filePath) 
    { 
     if (filePath == null) 
      throw new ArgumentNullException(nameof(filePath)); 

     using (var fac = new ImagingFactory()) 
     { 
      using (var dec = new SharpDX.WIC.BitmapDecoder(fac, filePath, DecodeOptions.CacheOnDemand)) 
      { 
       Frame = dec.GetFrame(0); 
      } 
     } 
    } 

    public WicBitmapSource(BitmapFrameDecode frame) 
    { 
     if (frame == null) 
      throw new ArgumentNullException(nameof(frame)); 

     Frame = frame; 
    } 

    public BitmapFrameDecode Frame { get; } 
    public override int PixelWidth => Frame.Size.Width; 
    public override int PixelHeight => Frame.Size.Height; 
    public override double Height => PixelHeight; 
    public override double Width => PixelWidth; 

    public override double DpiX 
    { 
     get 
     { 
      Frame.GetResolution(out double dpix, out double dpiy); 
      return dpix; 
     } 
    } 

    public override double DpiY 
    { 
     get 
     { 
      Frame.GetResolution(out double dpix, out double dpiy); 
      return dpiy; 
     } 
    } 

    public override System.Windows.Media.PixelFormat Format 
    { 
     get 
     { 
      // this is a hack as PixelFormat is not public... 
      // it would be better to do proper matching 
      var ct = typeof(System.Windows.Media.PixelFormat).GetConstructor(
       BindingFlags.Instance | BindingFlags.NonPublic, 
       null, 
       new[] { typeof(Guid) }, 
       null); 
      return (System.Windows.Media.PixelFormat)ct.Invoke(new object[] { Frame.PixelFormat }); 
     } 
    } 

    // mostly for GIFs support (indexed palette of 256 colors) 
    public override BitmapPalette Palette 
    { 
     get 
     { 
      using (var fac = new ImagingFactory()) 
      { 
       var palette = new Palette(fac); 
       try 
       { 
        Frame.CopyPalette(palette); 
       } 
       catch 
       { 
        // no indexed palette (PNG, JPG, etc.) 
        // it's a pity SharpDX throws here, 
        // it would be better to return null more gracefully as this is not really an error 
        // if you only want to support non indexed palette images, just return null for the property w/o trying to get a palette 
        return null; 
       } 

       var list = new List<Color>(); 
       foreach (var c in palette.GetColors<int>()) 
       { 
        var bytes = BitConverter.GetBytes(c); 
        var color = Color.FromArgb(bytes[3], bytes[2], bytes[1], bytes[0]); 
        list.Add(color); 
       } 
       return new BitmapPalette(list); 
      } 
     } 
    } 

    public override void CopyPixels(Int32Rect sourceRect, Array pixels, int stride, int offset) 
    { 
     if (offset != 0) 
      throw new NotSupportedException(); 

     Frame.CopyPixels(
      new SharpDX.Mathematics.Interop.RawRectangle(sourceRect.X, sourceRect.Y, sourceRect.Width, sourceRect.Height), 
      (byte[])pixels, stride); 
    } 

    public void Dispose() => Frame.Dispose(); 

    public override event EventHandler<ExceptionEventArgs> DecodeFailed; 
    public override event EventHandler DownloadCompleted; 
    public override event EventHandler<ExceptionEventArgs> DownloadFailed; 
    public override event EventHandler<DownloadProgressEventArgs> DownloadProgress; 

    protected override Freezable CreateInstanceCore() => throw new NotImplementedException(); 
}