/// <summary>
/// Decode the message and create a collection of event arguments
/// </summary>
/// <remarks>
/// One Windows message can result a group of events
/// </remarks>
/// <returns>An enumerator of thr resuting events</returns>
/// <param name="hWnd">the WndProc hWnd</param>
/// <param name="msg">the WndProc msg</param>
/// <param name="wParam">the WndProc wParam</param>
/// <param name="lParam">the WndProc lParam</param>
private IEnumerable <TouchEventArgs> DecodeMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam, float dpiX, float dpiY)
{
// More than one touchinput may be associated with a touch message,
// so an array is needed to get all event information.
int inputCount = User32.LoWord(wParam.ToInt32()); // Number of touch inputs, actual per-contact messages
TOUCHINPUT[] inputs; // Array of TOUCHINPUT structures
inputs = new TOUCHINPUT[inputCount]; // Allocate the storage for the parameters of the per-contact messages
try
{
// Unpack message parameters into the array of TOUCHINPUT structures, each
// representing a message for one single contact.
if (!User32.GetTouchInputInfo(lParam, inputCount, inputs, Marshal.SizeOf(inputs[0])))
{
// Get touch info failed.
throw new Exception("Error calling GetTouchInputInfo API");
}
// For each contact, dispatch the message to the appropriate message
// handler.
// Note that for WM_TOUCHDOWN you can get down & move notifications
// and for WM_TOUCHUP you can get up & move notifications
// WM_TOUCHMOVE will only contain move notifications
// and up & down notifications will never come in the same message
for (int i = 0; i < inputCount; i++)
{
TouchEventArgs touchEventArgs = new TouchEventArgs(HWndWrapper, dpiX, dpiY, ref inputs[i]);
yield return(touchEventArgs);
}
}
finally
{
User32.CloseTouchInputHandle(lParam);
}
}
private IEnumerable <TouchNotification> GenerateTouchNotifications(EventPattern <WMEventArgs> e)
{
var a = e.EventArgs;
var touchPointCount = a.WParam.LoWord();
if (touchPointCount > 0)
{
var touchPoints = new TOUCHINPUT[touchPointCount];
if (User32.GetTouchInputInfo(a.LParam, touchPointCount, touchPoints, Marshal.SizeOf(typeof(TOUCHINPUT))))
{
a.Handled = true;
try
{
RECT cr;
if (User32.GetClientRect(a.HWnd, out cr))
{
foreach (var touchPoint in touchPoints)
{
var position = new Point(touchPoint.x / 100, touchPoint.y / 100);
User32.ScreenToClient(a.HWnd, ref position);
var clientArea = new Size(cr.Width, cr.Height);
var id = touchPoint.dwID;
var primary = (touchPoint.dwFlags & Const.TOUCHEVENTF_PRIMARY) > 0;
var contactArea = (touchPoint.dwMask & Const.TOUCHINPUTMASKF_CONTACTAREA) > 0
? new Size(touchPoint.cxContact / 100, touchPoint.cyContact / 100)
: Size.Empty;
if ((touchPoint.dwFlags & Const.TOUCHEVENTF_DOWN) > 0)
{
yield return(new TouchDownNotification(position, clientArea, id, primary, contactArea, touchPoint.hSource.ToInt64(), e.Sender));
}
if ((touchPoint.dwFlags & Const.TOUCHEVENTF_MOVE) > 0)
{
yield return(new TouchMoveNotification(position, clientArea, id, primary, contactArea, touchPoint.hSource.ToInt64(), e.Sender));
}
if ((touchPoint.dwFlags & Const.TOUCHEVENTF_UP) > 0)
{
yield return(new TouchUpNotification(position, clientArea, id, primary, contactArea, touchPoint.hSource.ToInt64(), e.Sender));
}
}
}
}
finally
{
User32.CloseTouchInputHandle(a.LParam);
}
}
}
yield break;
}
/// <summary>
/// Decodes touch messages and calls corresponding methods on <see cref="PointerManager"/> class
/// </summary>
/// <param name="wParam">wParam</param>
/// <param name="lParam">lParam</param>
private void DecodeAndDispatchTouchMessages(IntPtr wParam, IntPtr lParam)
{
var inputsCount = User32.LoWord(wParam.ToInt32());
var inputs = new TOUCHINPUT[inputsCount];
try
{
if (!User32.GetTouchInputInfo(lParam, inputsCount, inputs, Marshal.SizeOf(typeof(TOUCHINPUT))))
{
throw new InvalidOperationException("Error calling GetTouchInfo API");
}
for (var i = 0; i < inputsCount; i++)
{
DecodeAndDispatchTouchPoint(inputs[i]);
}
}
finally
{
User32.CloseTouchInputHandle(lParam);
}
}
