Fine-tune the cut line point by point

Play

1. Double-click (or double-tap) the cut line. Small white squares show on it.
2. Drag a point to reshape the line.
3. Click the line between two points to add one.
4. Pick a point and tap the bin in the bar along the top (or press Delete) to remove it.
5. Tap Done (or press Escape).

Editing points locks the cut line, so it stays as you made it.