•void
CGrapheditView::drag_arc()
•{
• CDC * dc = GetDC();
• int old_mode = dc->SetROP2(R2_XORPEN);
• CPen * old_pen = (CPen *)dc->SelectStockObject(
WHITE_PEN );
• dc->MoveTo( start_drag );
• dc->LineTo( end_drag );
• dc->SelectObject( old_pen
);
• dc->SetROP2(old_mode);
• ReleaseDC(dc);
•}