Get Windows Touch/Gesture in an MFC application

在Win32的程式中, 我們可以在WndProc函式中, 接收WM_TOUCH和WM_GESTURE的訊息,來撰寫multi-touch application, 今天我們就來介紹,如果在MFC的應用程式中, 如何取得WM_TOUCH和WM_GESTURE message.
這是一個很簡單的範例, 首先, 產生一個MFC的Dialog, 當有touch發生時, 視窗的畫面會出現message box, 部分程式碼如下所示:

// Step 1: 宣告這個視窗接收 WM_TOUCH訊息
BEGIN_MESSAGE_MAP(CMFCTouchDlg, CDialog)

ON_MESSAGE(WM_TOUCH, OnTouch)

END_MESSAGE_MAP()


// Step 2: 註冊成 Touch Window

BOOL CMFCTouchDlg::OnInitDialog()
{
CDialog::OnInitDialog();

RegisterTouchWindow(this->GetSafeHwnd(), 0);
... ... ...
}


// Step 3: 加入實作 (當視窗收到 WM_TOUCH 指令時, 呼叫下面 method)

LRESULT CMFCTouchDlg::OnTouch(WPARAM wParam,LPARAM lParam)
{
::AfxMessageBox(L"Touch!!",0,0);

return 0;
}

執行畫面如下所示:






另一個範例則是當有手勢作用時, MFC dialog則會顯示手勢類型的message, 程式碼如下所示:

// Step 1: 宣告這個視窗接收 WM_GESTURE訊息

BEGIN_MESSAGE_MAP(CMFCTouchDlg, CDialog)

ON_MESSAGE(WM_GESTURE, OnGesture)

END_MESSAGE_MAP()


// Step 2: 開啟Rotate手勢

BOOL CMFCTouchDlg::OnInitDialog()
{
CDialog::OnInitDialog();

// Enable rotate gesture 
GESTURECONFIG config = { 0 };
config.dwWant = GC_ROTATE;
config.dwID = GID_ROTATE;
config.dwBlock = 0;
BOOL result = SetGestureConfig(
    this->GetSafeHwnd(),
    0,
    1,
    &config,
    sizeof(GESTURECONFIG));

... ... ...
}

// Step 3: 加入實作 (當視窗收到 WM_GESTURE 指令時, 呼叫下面 method)

LRESULT CMFCTouchDlg::OnGesture(WPARAM wParam,LPARAM lParam)
{
GESTUREINFO gi;
ZeroMemory(&gi,sizeof(GESTUREINFO));
gi.cbSize = sizeof(GESTUREINFO);
BOOL result = GetGestureInfo((HGESTUREINFO)lParam, &gi);

if(result)
{
switch(gi.dwID)
{

case GID_PAN:
::AfxMessageBox(L"Pan",0,0);
break;

case GID_ZOOM:
::AfxMessageBox(L"Zoom",0,0);
break;

case GID_ROTATE:
::AfxMessageBox(L"ROTATE",0,0);
break;

case GID_TWOFINGERTAP:
::AfxMessageBox(L"Two Finger Tap",0,0);
break;

case GID_PRESSANDTAP:
::AfxMessageBox(L"Press and Tap",0,0);
break;
}
}
return 0;
}


執行畫面如下所示: