/// <summary>
/// Distinguish between touch, pen, or mouse pointer events.
/// https://msdn.microsoft.com/en-us/library/windows/desktop/ms703320(v=vs.85).aspx
/// </summary>
/// <param name="hookData">Hook data to check</param>
/// <returns>Identified mouse event source</returns>
private static EventSource GetMouseEventSource(WinApi.MSLLHOOKSTRUCT hookData)
{
uint extra = (uint)hookData.dwExtraInfo;
bool isTouchOrPen = ((extra & 0xFFFFFF00) == 0xFF515700);
if (!isTouchOrPen)
{
return(EventSource.Mouse);
}
bool isTouch = ((extra & 0x00000080) == 0x00000080);
return(isTouch ? EventSource.Touch : EventSource.Pen);
}
/// <summary>
/// Intercepts mouse events, giving the option to change or swallow them.
/// This is gives extremely bad experience if/when the app hangs (i.e. debugger break),
/// as mouse events won't be processed, rendering mouse unusable until CallNextHookEx
/// is called. Fortunately, the OS will fix this by probably unregistering
/// the hook...
/// @TODO Minimize usage or find anternative.
/// </summary>
/// <param name="code"></param>
/// <param name="wParam"></param>
/// <param name="lParam"></param>
/// <returns></returns>
private IntPtr HookCallback(int code, IntPtr wParam, IntPtr lParam)
{
if (OnMouseLeaveBoundaries != null && code >= 0 && WinApi.WM.WM_MOUSEMOVE == (WinApi.WM)wParam)
{
WinApi.MSLLHOOKSTRUCT hookStruct = (WinApi.MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(WinApi.MSLLHOOKSTRUCT));
var coords = new Point(hookStruct.pt.x, hookStruct.pt.y);
// Boundary check
var isNowInAppBoundaries = IsInAppBoundaries(coords);
if (_isInAppBoundaries && !isNowInAppBoundaries)
{
var source = GetMouseEventSource(hookStruct);
var eventArgs = new EventArgs {
Source = source,
Coords = coords
};
OnMouseLeaveBoundaries.Invoke(null, eventArgs);
}
_isInAppBoundaries = isNowInAppBoundaries;
}
return(WinApi.CallNextHookEx(HookId, code, wParam, lParam));
}
