What looks like a normal pushbutton - until the user tries to click on it.
I wrote this many years ago for a friend. It is basically just a normal pushbutton, except that when the user tries to click on it, it moves out of the way making it practically un-clickable.
I have no idea what anyone would ever want to use such a control in their app, apart from wanting to be extremely annoying to users (and hey - don't we all get like that on occasion?) :)
The button is just a normal button with OnMouseMove overridden: (m_nJumpDistance is the distance in pixels to jump once the mouse has moved over the control).
The WM_SETFOCUS message has also been handled to bounce the focus back to the window that previously had focus, and PreSubclassWindow has been overridden to allow the removal of the WS_TABSTOP window style bit. This ensures that the user can't tab to the control.
void CTrickButton::OnMouseMove(UINT nFlags, CPoint point)
{
CWnd* pParent = GetParent();
if (!pParent) pParent = GetDesktopWindow();
CRect ParentRect; // Parent client area (Parent coords)
pParent->GetClientRect(ParentRect);
ClientToScreen(&point); // Convert point to parent coords
pParent->ScreenToClient(&point);
CRect ButtonRect; // Button Dimensions (Parent coords)
GetWindowRect(ButtonRect);
pParent->ScreenToClient(ButtonRect);
CPoint Center = ButtonRect.CenterPoint(); // Center of button (parent coords)
CRect NewButtonRect = ButtonRect; // New position (parent coords)
if (point.x > Center.x) // Mouse is right of center
{
if (ButtonRect.left > ParentRect.left + ButtonRect.Width() + m_nJumpDistance)
NewButtonRect -= CSize(ButtonRect.right - point.x + m_nJumpDistance, 0);
else
NewButtonRect += CSize(point.x - ButtonRect.left + m_nJumpDistance, 0);
}
else if (point.x < Center.x) // Mouse is left of center
{
if (ButtonRect.right < ParentRect.right - ButtonRect.Width() - m_nJumpDistance)
NewButtonRect += CSize(point.x - ButtonRect.left + m_nJumpDistance, 0);
else
NewButtonRect -= CSize(ButtonRect.right - point.x + m_nJumpDistance, 0);
}
if (point.y > Center.y) // Mouse is below center
{
if (ButtonRect.top > ParentRect.top + ButtonRect.Height() + m_nJumpDistance)
NewButtonRect -= CSize(0, ButtonRect.bottom - point.y + m_nJumpDistance);
else
NewButtonRect += CSize(0, point.y - ButtonRect.top + m_nJumpDistance);
}
else if (point.y < Center.y) // Mouse is above center
{
if (ButtonRect.bottom < ParentRect.bottom - ButtonRect.Height() - m_nJumpDistance)
NewButtonRect += CSize(0, point.y - ButtonRect.top + m_nJumpDistance);
else
NewButtonRect -= CSize(0, ButtonRect.bottom - point.y + m_nJumpDistance);
}
MoveWindow(NewButtonRect);
RedrawWindow();
CButton::OnMouseMove(nFlags, point);
}
void CTrickButton::OnSetFocus(CWnd* pOldWnd)
{
CButton::OnSetFocus(pOldWnd);
// Give the focus right back to the window that justn gave it to us
if (pOldWnd!=NULL && ::IsWindow(pOldWnd->GetSafeHwnd()))
pOldWnd->SetFocus();
}
void CTrickButton::PreSubclassWindow()
{
// Ensure that the TabStop style is removed from the control
ModifyStyle(WS_TABSTOP, 0);
CButton::PreSubclassWindow();
}31 May 2002 - updated to include removal of WM_TABSTOP, plus minor cleanup.