Different output in graph_draw interactive vs. pdf/png format

Hi,

I get some strange behavior when using graph_draw without specifying a format, and when I do specify an output format.

I've attached some examples. The edge markers get shifted around (midmarkers are set to None for all the edges, and the endmarkers to None for the dashed edges, and arrow for the solid edges). The correct behavior occurs in the cairo_draw call (without specifying a format).