title: C++ and Qt - Problem with 2D graphics
body: <p>Mission: Draw two lines with different color on one graph with automatic cliping, by adding points bit by bit.</p>
  
  <p>So, what am I doing. Create class GraphWidget, inherited from QGraphicsView. Create member of QGraphicsScene. Create 2 QPainterPath instances, and add them to graphicsScene.</p>
  
  <p>Then, I eventually call graphWidget.Redraw(), where call for QPainterPath.lineTo() for both instances. And I expect appearance of that lines of graphics view, but it doesn't.</p>
  
  <p>I tired from reading Qt's doc and forums. What am I doing wrong?</p>