void COpencvTestDlg: : OnLButtonDown (UINT nFlags, CPoint point) 
{
CRect myshowwinrect; 
GetDlgItem (IDC_SHOW_IAMGE_FC) - & gt; GetWindowRect (myshowwinrect);//get the screen coordinates 
The ScreenToClient (& amp; Myshowwinrect);//to the relative coordinates of the client area 
The CWnd * PWND=GetDlgItem (IDC_SHOW_IAMGE_FC); 
HWND HWND=PWND - & gt; GetSafeHwnd (); 
If (point x & gt;=myshowwinrect. Left & amp; & Point. X & lt;=myshowwinrect. Right & amp; & 
Point. The y & gt;=myshowwinrect. Top & amp; & Point. The y & lt;=myshowwinrect. Bottom)//mouse in the Picture on the Control controls the click 
{
M_startRect=TRUE;//the left mouse button click, setting can begin to draw a rectangle box 
M_startPoint=point;//record starting point 
M_OldPoint=point;//setting too old for starting point 
CClientDC dc (this);//get the device handle 
Dc. SetROP2 (R2_NOT);//drawing mode 
Dc. SelectStockObject (NULL_BRUSH);//do not use a brush 
Dc. A Rectangle (CRect (m_LastSartPoint m_LastStopPoint));//remove before painting rectangular 
} 

CDialogEx: : OnLButtonDown (nFlags, point); 
} 

Void COpencvTestDlg: : onm ouseMove (UINT nFlags, CPoint point) 
{
CClientDC dc (this);//get the device handle 
Dc. SetROP2 (R2_NOT);//drawing mode 
Dc. SelectStockObject (NULL_BRUSH);//do not use a brush 
If TRUE (==m_startRect)//according to whether there is a click determine whether can draw rectangle 
{
Dc. A Rectangle (CRect (m_startPoint m_OldPoint)); 
Dc. A Rectangle (CRect (m_startPoint, point)); 
M_OldPoint=point; 
} 
CDialogEx: onm ouseMove (nFlags, point); 
} 

Void COpencvTestDlg: : OnLButtonUp (UINT nFlags, CPoint point) 
{

M_startRect=FALSE;//reset draw a rectangle box sign 
////blanking last a rectangle (the principle the same as the rectangular box drawing principle drag with) 
CClientDC dc (this); 
Dc. SetROP2 (R2_NOT); 
Dc. SelectStockObject (NULL_BRUSH); 
Dc. A Rectangle (CRect (m_startPoint m_OldPoint)); 
Dc. A Rectangle (CRect (m_startPoint, point)); 
CDialogEx: : OnLButtonUp (nFlags, point); 
} 

The code above is ok, but the rectangular frame is black, I want to change the color, but the color changed after dc. SetROP2 (R2_NOT); Can not eliminate the rectangle before, how can help break? Or do you have any other methods? Grateful to

CodePudding user response:

Rewrite the CStatic class, OnPaint function will draw graphics in the background (or OnEarseBkGnd map background), then draw the other

CodePudding user response:

Hello, is not very understand, have the description of the specific point? MFC novice, thank you

CodePudding user response:

Dc. SetROP2 (R2_XORPEN)

CodePudding user response:

Dc. SetROP2 (R2_XORPEN) @ # 3, with the tested today, or not