if (!isHiddenValue(tickDate.getTime())) {
                // work out the value, label and position
                String tickLabel;
                DateFormat formatter = getDateFormatOverride();
                if (formatter != null) {
                    tickLabel = formatter.format(tickDate);
                }
                else {
                    tickLabel = this.tickUnit.dateToString(tickDate);
                }
                TextAnchor anchor = null;
                TextAnchor rotationAnchor = null;
                double angle = 0.0;
                if (isVerticalTickLabels()) {
                    anchor = TextAnchor.BOTTOM_CENTER;
                    rotationAnchor = TextAnchor.BOTTOM_CENTER;
                    if (edge == RectangleEdge.LEFT) {
                        angle = -Math.PI / 2.0;
                    }
                    else {
                        angle = Math.PI / 2.0;
                    }
                }
                else {
                    if (edge == RectangleEdge.LEFT) {
                        anchor = TextAnchor.CENTER_RIGHT;
                        rotationAnchor = TextAnchor.CENTER_RIGHT;
                    }
                    else {
                        anchor = TextAnchor.CENTER_LEFT;
                        rotationAnchor = TextAnchor.CENTER_LEFT;
                    }
                }

                Tick tick = new DateTick(tickDate, tickLabel, anchor,
                        rotationAnchor, angle);
                result.add(tick);
                tickDate = unit.addToDate(tickDate, this.timeZone);
            }
            else {
                tickDate = unit.rollDate(tickDate, this.timeZone);