public void MouseClicked() { Point mousePoint = new Point(MouseX, MouseY); bool isShiftDown = Keyboard.IsKeyDown(Key.LeftShift); bool isCtrlDown = Keyboard.IsKeyDown(Key.LeftCtrl); if (isShiftDown) { if (isCtrlDown) { canvas.RemoveClosestPoint(mousePoint); } else { canvas.AddPoint(mousePoint); } } else { if (isCtrlDown) { canvas.ProcessLine(mousePoint); } else { canvas.ProcessPoint(mousePoint); } } }