c++ - 请问在MFC对话框中，如何获取鼠标相对于对话框中CStatic控件左上角的坐标？

Question

在我的对话框中有一个CStatic控件，我现在希望在CStatic空间上进行绘图，并且同时能够获取鼠标相对于CStatic控件上左上角的坐标并将坐标保存下来，请问应该如何去做？
非常感谢。

Answer 1

Time is short, so I’ll answer half of it first.
Getting the coordinates of the mouse pointer in the window is very simple. I used the WM_MOUSEMOVE message response function here. Let’s take a look at my sample window composition first:

The following tags are used to output the results. Then go directly to the code to see:

void CStaticDrawDlg::OnMouseMove(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default
    TCHAR buffer[255];        //用来保存结果的字符串
    memset(buffer, 0, 255);

    CRect staticRect;        //用来保存static控件的大小
    (GetDlgItem(IDC_STATIC_DRAW))->GetWindowRect(&staticRect);    //获取static大小
    ScreenToClient(&staticRect);        //把相对屏幕的坐标转换成相对当前窗口客户区的大小

    CPoint insidePoint;                //用来保存鼠标指针相对static控件坐标
    insidePoint.x = point.x - staticRect.left;    //当前相对客户区的x坐标减去static的左侧位置即为鼠标指针相对static的坐标
    insidePoint.y = point.y - staticRect.top;    //同上

    //下面把结果显示到另一个static控件上
    wsprintf(buffer, 
        _T("当前鼠标指针相对于窗口的x坐标为%d，y坐标为%d\n相对于用来绘图的static的x坐标为%d，y坐标为%d"), 
        point.x, point.y, insidePoint.x, insidePoint.y);
    (GetDlgItem(IDC_STATIC_OUTPUT))->SetWindowText(buffer);
    CDialogEx::OnMouseMove(nFlags, point);
}

The above is about the mouse pointer issue.
As for drawing on static, because it responds to OnPaint first, you cannot draw on static in OnPaint. You can use a timer to bypass this problem and complete static drawing in the Timer's event response function. Or derive your own static class from CStatic class and override

virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);

This virtual function.