A golf ball tracer for your swing videos, right from your phone. Pick a video. Tap two points. Watch the ball trail animate across your shot. That clip you took at the range or on the course, now with the ball flight traced in. ■ Three steps. That's it. 1. Pick a clip Import a video from your photo library. 2. Tap two points Tap where the ball launched and where it landed. The app automatically fits a natural parabola between the two points. Drag the start/end pins or the two…