Advanced MFC Programming

Chapter 12. Screen Capturing & Printing
select a window. The new dialog template is IDD_DIALOG_SELECT, and the class associated with it is
CSelDlg. To make the interface user friendly, mouse cursor will be changed when the user is selecting a
window (With left button held down). In the sample, a cursor resource IDC_CURSOR_SELECT is added for
this purpose. The cursor is loaded in the constructor of CSelDlg and its handle is stored in variable
CSelDlg::m_curSelect. In the dialog box template, an icon that contains the cursor is displayed. If the user
click on this icon, it will be changed to a blank icon and at the same time, the cursor will be customized to
IDC_CURSOR_SELECT. If the user releases the mouse button, everything will be resumed. This will give the
user a feeling that the mouse clicking actually picks up the cursor (Figure 12-3).
The icons displayed in the dialog box are also stored as resources. Their IDs are IDI_ICON_CURSOR and
IDI_ICON_BLANK. Also, they are loaded in the class constructor and are displayed in the dialog box by
calling function CStatic::SetIcon(…). The control used to display the icon is a static control (Actually it
is added as a “Picture” control). In the property sheet “Picture Properties”, we can choose the type of
images that will be displayed, such as bitmap or icon (Figure 12-4).
Messages WM_LBUTTONDOWN, WM_LBUTTONUP and WM_MOUSEMOVE are handled to let the user select a
window. When the left button is pressed down, we check if it hits the icon contained in the dialog box. If
so, we set window capture for the dialog box, change the mouse cursor, and change icon IDI_ICON_CURSOR
to IDI_ICON_BLANK:
void CSelDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
CRect rect;
}
CDialog::OnLButtonDown(nFlags, point);
GetDlgItem(IDC_STATIC_CURSOR)->GetWindowRect(rect);
ScreenToClient(rect);
if(rect.PtInRect(point))
{
SetCapture();
((CStatic *)GetDlgItem(IDC_STATIC_CURSOR))->SetIcon(m_iconBlank);
GetDlgItem(IDC_STATIC_CURSOR)->Invalidate();
m_curSave=::SetCursor(m_curSelect);
m_bCaptureOn=TRUE;
m_rectSelect=CRect(0, 0, 0, 0);
m_hWnd=NULL;
}
If the user clicks on this icon, it will
disappear. At the same time, the
mouse cursor will be changed to this
shape. This will give the user an
impression that the mouse clicking
picks up the cursor.
Figure 12-3. Dialog box used for selecting window
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