+ /**
+ * Computes the feature colour for a given sequence and column position,
+ * taking into account sequence feature locations, feature colour schemes,
+ * render ordering, feature and feature group visibility, and transparency.
+ * <p>
+ * The graphics argument should be provided if transparency is applied
+ * (getTransparency() < 1). With feature transparency, visible features are
+ * written to the graphics context and the composite colour may be read off
+ * from it. In this case, the returned feature colour is not the composite
+ * colour but that of the last feature drawn.
+ * <p>
+ * If no transparency applies, then the graphics argument may be null, and the
+ * returned colour is the one that would be drawn for the feature.
+ * <p>
+ * Returns null if there is no visible feature at the position.
+ * <p>
+ * This is provided to support rendering of feature colours other than on the
+ * sequence alignment, including by structure viewers and the overview window.
+ * Note this method takes no account of whether the sequence or column is
+ * hidden.
+ *
+ * @param sequence
+ * @param column
+ * @param g
+ * @return
+ */
+ Color findFeatureColour(SequenceI sequence, int column, Graphics g);
+
+ /**
+ * trigger the feature discovery process for a newly created feature renderer.
+ */