Home team ahead, 4.5 innings is complete game. 5 innings if visitor leads. Both if game cannot be resumed, of course.
Less than that, start over from scratch another day.
After that, if visitor takes the lead in the top half, the game must be resumed from that point. If home team leads, game can be called complete or resumed at any point.
In this case, if not tonight, resumed probably tomorrow. But it will be suspended if not resumed.
Edit: Ninja'd.
And I bailed...on the blue line