Mouse Over Special Efects
Posted
by C. Lung
on May 1st, 1999
I used 16-bit color bitmaps, so if your resolution is set to 256 colors, it will probably not look very pleasing.
This is an updated version to my original posting. I have taken the comments that
I received and have come up with a better version of the code.
My thanks to Anatoly Ivasyuk, Jacques, and Dave Montgomery for their comments.
I needed a way to change a bitmap when the mouse went over it, and also to detect
if the user pressed the mouse button. What I came up with was the following quick
and easy solution.
void CMouseTrackDlg::OnMouseMove(UINT nFlags, CPoint point)
{
m_Picture.GetWindowRect(&rect);
ClientToScreen(&point);
if (rect.PtInRect(point))
{
m_Picture.SetBitmap(bitmap2);
}
else
{
m_Picture.SetBitmap(bitmap1);
}
CDialog::OnMouseMove(nFlags, point);
}
All I did here was check to see if the mouse had entered into the
bitmap. If it had, a different bitmap is displayed.
void CMouseTrackDlg::OnLButtonUp(UINT nFlags, CPoint point)
{
m_Picture.GetWindowRect(&rect);
ClientToScreen(&point);
if(rect.PtInRect(point))
AfxMessageBox("You pressed the Visual C++ bitmap", MB_OK);
CDialog::OnLButtonUp(nFlags, point);
}
Here I just wanted to check if the user pressed the left mouse button
while inside the bitmap.
Make sure to load the bitmaps:
BOOL CMouseTrackDlg::OnInitDialog()
{
CDialog::OnInitDialog();
// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon
// TODO: Add extra initialization here
bitmap1.LoadBitmap(IDB_BITMAP1);
bitmap2.LoadBitmap(IDB_BITMAP2);
return TRUE; // return TRUE unless you set the focus to a control
}
And make sure to initially declare the bitmaps, in this case there are only two.
In addition to the bitmaps, you can see I declared a CRect which is used in the
code above.
private: CRect rect; CBitmap bitmap1; CBitmap bitmap2;Finally:
void CMouseTrackDlg::OnActivate(UINT nState, CWnd* pWndOther, BOOL bMinimized)
{
CDialog::OnActivate(nState, pWndOther, bMinimized);
if(nState == WA_INACTIVE)
m_Picture.SetBitmap(bitmap1);
}
Here I mapped the OnActivate message to the dialog (CMouseTrackDlg) and if the
dialog has lost its focus, then the orginal bitmap is displayed.

Comments
This is not so good...
Posted by turkinz on 05/08/2004 08:57amThe common problem with this and similar examples is that if you move your mouse over the button, and then pretty fast move it off the button and window area, the button still remains highlighted (as if there was the mouse pointer over it, but it's not). Look at Internet Explorer web pages. It's impossible to catch that kind of bug, there. I think they used some kind of Timer-based checking.
ReplyDoing this to more that one image
Posted by Legacy on 01/20/2000 12:00amOriginally posted by: Hades
Is there a way to use this code on multiple images, so you can have two buttons that change?
ReplyWM_MOUSELEAVE
Posted by Legacy on 04/07/1999 12:00amOriginally posted by: Jacques
you can have a look at WM_MOUSELEAVE
if you are under Win NT 4 or Win98
WM_MOUSELEAVE
The WM_MOUSELEAVE message is posted to a window when the cursor leaves the client area of the window specified in a prior call to TrackMouseEvent.
WM_MOUSEHOVER
lParam = 0;
wParam = 0;
Return Values
If an application processes this message, it should return zero.
Remarks
ReplyAll tracking requested by TrackMouseEvent is canceled when this message is generated. The application must call TrackMouseEvent when the mouse re-enters its window if it requires further tracking of mouse hover behavior.