+ /**
+ * Adjust sequence position for page up. Fires a property change event.
+ */
+ public void pageUp()
+ {
+ if (wrappedMode)
+ {
+ setStartRes(Math.max(0, getStartRes() - getViewportWidth()));
+ }
+ else
+ {
+ setViewportStartAndHeight(startSeq - (endSeq - startSeq),
+ getViewportHeight());
+ }
+ }
+
+ /**
+ * Adjust sequence position for page down. Fires a property change event.
+ */
+ public void pageDown()
+ {
+ if (wrappedMode)
+ {
+ /*
+ * if height is more than width (i.e. not all sequences fit on screen),
+ * increase page down to height
+ */
+ int newStart = getStartRes()
+ + Math.max(getViewportHeight(), getViewportWidth());
+
+ /*
+ * don't page down beyond end of alignment, or if not all
+ * sequences fit in the visible height
+ */
+ if (newStart < getVisibleAlignmentWidth())
+ {
+ setStartRes(newStart);
+ }
+ }
+ else
+ {
+ setViewportStartAndHeight(endSeq, getViewportHeight());
+ }
+ }
+
+ public void setWrappedMode(boolean wrapped)
+ {
+ wrappedMode = wrapped;
+ }
+
+ public boolean isWrappedMode()
+ {
+ return wrappedMode;
+ }
+
+ /**
+ * Answers the vertical scroll position (0..) to set, given the visible column
+ * that is at top left.
+ *
+ * <pre>
+ * Example:
+ * viewport width 40 columns (0-39, 40-79, 80-119...)
+ * column 0 returns scroll position 0
+ * columns 1-40 return scroll position 1
+ * columns 41-80 return scroll position 2
+ * etc
+ * </pre>
+ *
+ * @param topLeftColumn
+ * (0..)
+ * @return
+ */
+ public int getWrappedScrollPosition(final int topLeftColumn)
+ {
+ int w = getViewportWidth();
+
+ /*
+ * visible whole widths
+ */
+ int scroll = topLeftColumn / w;
+
+ /*
+ * add 1 for a part width if there is one
+ */
+ scroll += topLeftColumn % w > 0 ? 1 : 0;
+
+ return scroll;
+ }
+
+ /**
+ * Answers the maximum wrapped vertical scroll value, given the column
+ * position (0..) to show at top left of the visible region.
+ *
+ * @param topLeftColumn
+ * @return
+ */
+ public int getWrappedMaxScroll(int topLeftColumn)
+ {
+ int scrollPosition = getWrappedScrollPosition(topLeftColumn);
+
+ /*
+ * how many more widths could be drawn after this one?
+ */
+ int columnsRemaining = getVisibleAlignmentWidth() - topLeftColumn;
+ int width = getViewportWidth();
+ int widthsRemaining = columnsRemaining / width
+ + (columnsRemaining % width > 0 ? 1 : 0) - 1;
+ int maxScroll = scrollPosition + widthsRemaining;
+
+ return maxScroll;
+ }