/// <summary>
/// Return the point to sync the window to. The point is in the coordinate
/// space of the image, which is the same as the client coordinate space
/// of the hosted window. This function returns null if the input should
/// not be synchronized for this redirected window.
/// </summary>
/// <returns></returns>
private POINT?GetInputSyncPoint(int xScreen, int yScreen)
{
POINT?ptClient = null;
HwndSource currentHwndSource = CurrentHwndSource;
if (currentHwndSource != null)
{
var dpiScaleToWpfScale = CurrentHwndSource.CompositionTarget.TransformToDevice; // New!
HWND hwndCapture = NativeMethods.GetCapture();
if (hwndCapture != HWND.NULL)
{
// The mouse is captured, so only sync input if the mouse is
// captured to a hosted window within us.
HWND root = NativeMethods.GetAncestor(hwndCapture, GA.ROOT);
if (_redirectedWindow.Handle == root)
{
// The HWND with capture is within us.
// Transform the screen coordinates into the local coordinates.
Point pt = new Point(xScreen, yScreen);
pt = currentHwndSource.TransformScreenToClient(pt);
pt = currentHwndSource.TransformClientToRoot(pt);
pt = currentHwndSource.RootVisual.TransformToDescendant(this).Transform(pt);
pt = dpiScaleToWpfScale.Transform(pt); // New!
ptClient = new POINT {
x = (int)Math.Round(pt.X), y = (int)Math.Round(pt.Y)
};
}
}
else
{
// The mouse is not captured, so only sync input if the mouse
// is over our element.
// Convert the mouse coordinates to the client coordinates of the
// HwndSource.
Point pt = new Point(xScreen, yScreen);
pt = currentHwndSource.TransformScreenToClient(pt);
pt = currentHwndSource.TransformClientToRoot(pt);
RedirectedHwndHost hit = ((UIElement)currentHwndSource.RootVisual).InputHitTest(pt) as RedirectedHwndHost;
if (hit == this)
{
// Transform into the coordinate space of the
// RedirectedHwndHost element.
var xfrm = currentHwndSource.RootVisual.TransformToDescendant(hit);
pt = xfrm.Transform(pt);
pt = dpiScaleToWpfScale.Transform(pt); // New!
ptClient = new POINT {
x = (int)Math.Round(pt.X), y = (int)Math.Round(pt.Y)
};
}
}
}
return(ptClient);
}