private void InitialiseThumbnail(IntPtr source)
{
if (IntPtr.Zero != thumb)
{
// release the old thumbnail
ReleaseThumbnail();
}
if (IntPtr.Zero != source)
{
// find our parent hwnd
target = (HwndSource)HwndSource.FromVisual(this);
// if we have one, we can attempt to register the thumbnail
if (target != null && 0 == DwmRegisterThumbnail(target.Handle, source, out this.thumb))
{
ThumbnailProperties props = new ThumbnailProperties();
props.Visible = this.Visibility == Visibility.Visible;
props.SourceClientAreaOnly = this.ClientAreaOnly;
props.Opacity = (byte)(255 * this.Opacity);
props.Flags = ThumbnailFlags.Visible | ThumbnailFlags.SourceClientAreaOnly | ThumbnailFlags.Opacity;
DwmUpdateThumbnailProperties(thumb, ref props);
}
}
}
internal bool Create()
{
lock (MainForm.Sync)
{
//attempt to register this darkages process to a thumbnail, 0 for success
if (NativeMethods.DwmRegisterThumbnail(MainForm.Handle, Client.MainWindowHandle, out ThumbnailHandle) == 0)
{
//create a new thumbnail properties struct and set properties/location/size/etc
var tProperties = new ThumbnailProperties
{
Visible = true,
Flags = ThumbnailFlags.Visible | ThumbnailFlags.RectDestination | ThumbnailFlags.Opacity |
ThumbnailFlags.SourceClientAreaOnly,
Opacity = 255,
OnlyClientRect = true
};
//now determine the location of the thumbnail
//first we convert this usercontrol's rect to a screen rect
var screenRect = RectangleToScreen(DisplayRectangle);
//clientrect will represent the mainform co-ordinates of this form
var clientRect = MainForm.RectangleToClient(screenRect);
tProperties.DestinationRect = new(clientRect.Left, clientRect.Top + 24, clientRect.Left + clientRect.Width,
clientRect.Top + clientRect.Height);
//update the thumbnail
_ = NativeMethods.DwmUpdateThumbnailProperties(ThumbnailHandle, ref tProperties);
return(true);
}
return(false);
}
}
public void SetDestinationRect(Rect destinationRect)
{
ThumbnailProperties properties = new ThumbnailProperties {
Flags = ThumbnailFlags.RectDestination,
Destination = destinationRect
};
DwmUpdateThumbnailProperties(thumbnail, ref properties);
}
public void SetSourceRect(Rect sourceRect)
{
ThumbnailProperties properties = new ThumbnailProperties {
Flags = ThumbnailFlags.RectSource,
Source = sourceRect
};
DwmUpdateThumbnailProperties(thumbnail, ref properties);
}
private void UpdateThumbnail()
{
if (IntPtr.Zero != thumb)
{
ThumbnailProperties props = new ThumbnailProperties
{
Visible = this.Visibility == Visibility.Visible,
SourceClientAreaOnly = this.ClientAreaOnly,
Opacity = (byte)(255 * this.Opacity),
Flags = ThumbnailFlags.Visible | ThumbnailFlags.SourceClientAreaOnly | ThumbnailFlags.Opacity
};
DwmUpdateThumbnailProperties(thumb, ref props);
}
}
internal void Destroy()
{
lock (MainForm.Sync)
{
//set thumbnail to invisible incase its not dead yet
var tProps = new ThumbnailProperties
{
Visible = false,
Flags = ThumbnailFlags.Visible
};
//unregister the thumbnail
_ = NativeMethods.DwmUnregisterThumbnail(ThumbnailHandle);
_ = NativeMethods.DwmUpdateThumbnailProperties(ThumbnailHandle, ref tProps);
Hide();
MainForm = null !;
Client = null !;
}
}
internal static extern int DwmUpdateThumbnailProperties(IntPtr hThumbnailId, ref ThumbnailProperties thumbProps);
protected static extern void DwmUpdateThumbnailProperties(IntPtr thumbnailHandle, ref ThumbnailProperties properties);
public static extern int DwmUpdateThumbnailProperties(IntPtr HThumbnail, ref ThumbnailProperties props);
public static extern int UpdateThumbnailProperties(IntPtr HThumbnail, ref ThumbnailProperties props);
public static extern void DwmUpdateThumbnailProperties( IntPtr thumbnailHandle, ref ThumbnailProperties properties );
// this is where the magic happens
private void Thumbnail_LayoutUpdated(object sender, EventArgs e)
{
if (IntPtr.Zero == thumb)
{
InitialiseThumbnail(this.Source);
}
if (IntPtr.Zero != thumb)
{
if (!target.RootVisual.IsAncestorOf(this))
{
//we are no longer in the visual tree
ReleaseThumbnail();
return;
}
DwmQueryThumbnailSourceSize(this.thumb, out WPF.SysSize size);
Rect visib = WPF.GetVisibleArea(this);
ThumbnailProperties props = new ThumbnailProperties();
if (visib == Rect.Empty)
{
props.Visible = false;
props.Flags = ThumbnailFlags.Visible;
}
else
{
double ratioSrc = (double)size.Width / (double)size.Height;
double ratioDest = visib.Width / visib.Height;
// Center the thumbnail in the visible area
double newSize;
if (ratioSrc > ratioDest)
{
newSize = visib.Height * ratioDest / ratioSrc;
visib.Y += (visib.Height - newSize) / 2.0;
visib.Height = newSize;
}
else
{
newSize = visib.Width * ratioSrc / ratioDest;
visib.X += (visib.Width - newSize) / 2.0;
visib.Width = newSize;
}
// Translate to screen pixels
Point a = target.RootVisual.PointToScreen(visib.TopLeft);
Point b = target.RootVisual.PointToScreen(visib.BottomRight);
Point w = Application.Current.MainWindow.PointToScreen(new Point(0, 0));
props.Destination = new WPF.SysRect(
(int)Math.Ceiling(a.X - w.X), (int)Math.Ceiling(a.Y - w.Y),
(int)Math.Ceiling(b.X - w.X), (int)Math.Ceiling(b.Y - w.Y));
props.Visible = this.Visibility == Visibility.Visible;
props.Flags = ThumbnailFlags.Visible | ThumbnailFlags.RectDestination;
}
DwmUpdateThumbnailProperties(thumb, ref props);
}
}
internal static extern int DwmUpdateThumbnailProperties(IntPtr hThumbnailId, ref ThumbnailProperties thumbProps);
internal static extern int DwmUpdateThumbnailProperties(IntPtr HThumbnail, ref ThumbnailProperties props);
private static extern int DwmUpdateThumbnailProperties(IntPtr thumb, ref ThumbnailProperties props);
