namespace MyBehaviorAssembly
{
public class PixelSupportBehavior : Behavior<Image>
{
public static readonly DependencyProperty PixelsProperty = DependencyProperty.Register(
"Pixels", typeof (IList<byte>), typeof (PixelSupportBehavior), new PropertyMetadata(default(IList<byte>),OnPixelsChanged));
private static void OnPixelsChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var b = (PixelSupportBehavior) d;
var pixels = (IList<byte>) e.NewValue;
b.RenderPixels(pixels);
}
public IList<byte> Pixels
{
get { return (IList<byte>) GetValue(PixelsProperty); }
set { SetValue(PixelsProperty, value); }
}
public static readonly DependencyProperty PixelFormatProperty = DependencyProperty.Register(
"PixelFormat", typeof (PixelFormat), typeof (PixelSupportBehavior), new PropertyMetadata(PixelFormats.Default,OnPixelFormatChanged));
private static void OnPixelFormatChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var b = (PixelSupportBehavior) d;
var pixelFormat = (PixelFormat) e.NewValue;
if(pixelFormat==PixelFormats.Default)
return;
b._pixelFormat = pixelFormat;
b.InitializeBufferIfAttached();
}
public PixelFormat PixelFormat
{
get { return (PixelFormat) GetValue(PixelFormatProperty); }
set { SetValue(PixelFormatProperty, value); }
}
public static readonly DependencyProperty PixelWidthProperty = DependencyProperty.Register(
"PixelWidth", typeof (int), typeof (PixelSupportBehavior), new PropertyMetadata(default(int),OnPixelWidthChanged));
private static void OnPixelWidthChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var b = (PixelSupportBehavior)d;
var value = (int)e.NewValue;
if(value<=0)
return;
b._pixelWidth = value;
b.InitializeBufferIfAttached();
}
public int PixelWidth
{
get { return (int) GetValue(PixelWidthProperty); }
set { SetValue(PixelWidthProperty, value); }
}
public static readonly DependencyProperty PixelHeightProperty = DependencyProperty.Register(
"PixelHeight", typeof (int), typeof (PixelSupportBehavior), new PropertyMetadata(default(int),OnPixelHeightChanged));
private static void OnPixelHeightChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var b = (PixelSupportBehavior)d;
var value = (int)e.NewValue;
if (value <= 0)
return;
b._pixelHeight = value;
b.InitializeBufferIfAttached();
}
public int PixelHeight
{
get { return (int) GetValue(PixelHeightProperty); }
set { SetValue(PixelHeightProperty, value); }
}
public static readonly DependencyProperty DpiXProperty = DependencyProperty.Register(
"DpiX", typeof (int), typeof (PixelSupportBehavior), new PropertyMetadata(96,OnDpiXChanged));
private static void OnDpiXChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var b = (PixelSupportBehavior)d;
var value = (int)e.NewValue;
if (value <= 0)
return;
b._dpiX = value;
b.InitializeBufferIfAttached();
}
public int DpiX
{
get { return (int) GetValue(DpiXProperty); }
set { SetValue(DpiXProperty, value); }
}
public static readonly DependencyProperty DpiYProperty = DependencyProperty.Register(
"DpiY", typeof (int), typeof (PixelSupportBehavior), new PropertyMetadata(96,OnDpiYChanged));
private static void OnDpiYChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var b = (PixelSupportBehavior)d;
var value = (int)e.NewValue;
if (value <= 0)
return;
b._dpiY = value;
b.InitializeBufferIfAttached();
}
public int DpiY
{
get { return (int) GetValue(DpiYProperty); }
set { SetValue(DpiYProperty, value); }
}
private IntPtr _backBuffer = IntPtr.Zero;
private int _bytesPerPixel;
private const int BitsPerByte = 8;
private int _pixelWidth;
private int _pixelHeight;
private int _dpiX;
private int _dpiY;
private Int32Rect _imageRectangle;
private readonly GCHandle _defaultGcHandle = new GCHandle();
private PixelFormat _pixelFormat;
private int _byteArraySize;
private WriteableBitmap _bitMap;
private bool _attached;
protected override void OnAttached()
{
_attached = true;
InitializeBufferIfAttached();
}
private void InitializeBufferIfAttached()
{
if(_attached==false)
return;
ReevaluateBitsPerPixel();
RecomputeByteArraySize();
ReinitializeImageSource();
}
private void ReevaluateBitsPerPixel()
{
var f = _pixelFormat;
if (f == PixelFormats.Default)
{
_bytesPerPixel = 0;
return;
};
_bytesPerPixel = f.BitsPerPixel/BitsPerByte;
}
private void ReinitializeImageSource()
{
var f = _pixelFormat;
var h = _pixelHeight;
var w = _pixelWidth;
if (w<=0|| h<=0 || f== PixelFormats.Default)
return;
_imageRectangle = new Int32Rect(0, 0, w, h);
_bitMap = new WriteableBitmap(w, h, _dpiX, _dpiY, f, null);
_backBuffer = _bitMap.BackBuffer;
AssociatedObject.Source = _bitMap;
}
private void RenderPixels(IList<byte> pixels)
{
if (pixels == null)
{
return;
}
var buffer = _backBuffer;
if (buffer == IntPtr.Zero)
return;
var size = _byteArraySize;
var gcHandle = _defaultGcHandle;
var allocated = false;
var bitMap = _bitMap;
var rect = _imageRectangle;
var w = _pixelWidth;
var locked = false;
try
{
gcHandle = GCHandle.Alloc(pixels, GCHandleType.Pinned);
allocated = true;
bitMap.Lock();
locked = true;
var ptr = gcHandle.AddrOfPinnedObject();
_bitMap.WritePixels(rect, ptr, size,w);
}
finally
{
if(locked)
bitMap.Unlock();
if (allocated)
gcHandle.Free();
}
}
private void RecomputeByteArraySize()
{
var h = _pixelHeight;
var w = _pixelWidth;
var bpp = _bytesPerPixel;
if (w<=0|| h<=0 || bpp<=0)
return;
_byteArraySize = (w * h * bpp);
}
public PixelSupportBehavior()
{
_pixelFormat = PixelFormats.Default;
}
}
}