matplotlib Code

//dot -Tps -o ../figures/show.ps show.dot
digraph G{
    graph [rankdir="LR"
           ];

show->expose->FigureCanvasDraw->NewRenderer->FigureDraw->CanvasUpdated;
expose[label="expose event\nfor all figures"];
FigureCanvasDraw[label="FigureCanvas.draw()"];
NewRenderer[label="creates a backend dependent\n renderer instance"];
FigureDraw[label="canvas.figure.draw(renderer)"];
CanvasUpdated[label="backend canvas updated"];
}