MFC中鼠标在picture控件中画矩形提取感兴趣区域

void CPicProcessDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
	// TODO:  在此添加消息处理程序代码和/或调用默认值
	GetCursorPos(&sel_pos);
	GetDlgItem(IDC_Pic1)->GetWindowRect(&rect);
	if (rect.PtInRect(sel_pos))
	{
		ClipCursor(&rect);
		rect_width = rect.right - rect.left;
		rect_height = rect.bottom - rect.top;
		xscale = m_image.cols / rect_width;
		yscale = m_image.rows / rect_height;

		m_startPoint.x = (sel_pos.x - rect.left) * xscale;
		m_startPoint.y = (sel_pos.y - rect.top) * yscale;
	}
	move_flag = true;

	CDialogEx::OnLButtonDown(nFlags, point);
}

void CPicProcessDlg::OnMouseMove(UINT nFlags, CPoint point)
{
	// TODO:  在此添加消息处理程序代码和/或调用默认值
	if (move_flag)
	{
		GetCursorPos(&sel_pos);
		GetDlgItem(IDC_Pic1)->GetWindowRect(&rect);
		if (rect.PtInRect(sel_pos))
		{
			rect_width = rect.right - rect.left;
			rect_height = rect.bottom - rect.top;
			m_endPoint.x = (sel_pos.x - rect.left) * xscale;
			m_endPoint.y = (sel_pos.y - rect.top) * yscale;
		}
		move_flag = false;
	}

	up_flag = true;

	CDialogEx::OnMouseMove(nFlags, point);
}



void CPicProcessDlg::OnLButtonUp(UINT nFlags, CPoint point)
{
	// TODO:  在此添加消息处理程序代码和/或调用默认值
	if (up_flag)
	{
		GetCursorPos(&sel_pos);
		GetDlgItem(IDC_Pic1)->GetWindowRect(&rect);
		if (rect.PtInRect(sel_pos))
		{
			ClipCursor(NULL);
			rect_width = rect.right - rect.left;
			rect_height = rect.bottom - rect.top;

			m_endPoint.x = (sel_pos.x - rect.left) * xscale;
			m_endPoint.y = (sel_pos.y - rect.top) * yscale;
		}
	}
	up_flag = false;

	ROIrect.x = m_startPoint.x;
	ROIrect.y = m_startPoint.y;
	ROIrect.width = m_endPoint.x - m_startPoint.x;
	ROIrect.height = m_endPoint.y - m_startPoint.y;

	rectangle(m_tmpGray, ROIrect, Scalar(0, 255, 0));
	DrawImgToHDC(m_tmpGray, IDC_Pic1);

	ROI = m_repairImg(ROIrect);
	CDialogEx::OnLButtonUp(nFlags, point);
}