- * Paints the background layer of the signal with a QPainter
- * @param p the QPainter to paint into.
- * @param left the x-coordinate of the left edge of the signal.
- * @param right the x-coordinate of the right edge of the signal.
- **/
- void paint_back(QPainter &p, int left, int right);
+ * Returns the offset to show the drag handle.
+ */
+ int scale_handle_offset() const;
+
+ /**
+ * Handles the scale handle being dragged to an offset.
+ * @param offset the offset the scale handle was dragged to.
+ */
+ void scale_handle_dragged(int offset);