* @param vertical policy
* The assumed vertical scroll policy; musn't be <tt>FILL_TO_CAPACITY</tt>
*/
private void layoutHelper(ScrollBarPolicy horizontalPolicy,
ScrollBarPolicy verticalPolicy) {
ScrollPane scrollPane = (ScrollPane)getComponent();
int width = getWidth();
int height = getHeight();
boolean constrainWidth = (horizontalPolicy == ScrollBarPolicy.FILL);
boolean constrainHeight = (verticalPolicy == ScrollBarPolicy.FILL);
Component view = scrollPane.getView();
Component columnHeader = scrollPane.getColumnHeader();
Component rowHeader = scrollPane.getRowHeader();
Component corner = scrollPane.getCorner();
int rowHeaderWidth = 0;
if (rowHeader != null) {
rowHeaderWidth = rowHeader.getPreferredWidth(-1);
}
int columnHeaderHeight = 0;
if (columnHeader != null) {
columnHeaderHeight = columnHeader.getPreferredHeight(-1);
}
int previousViewWidth, viewWidth = 0;
int previousViewHeight, viewHeight = 0;
int previousHorizontalScrollBarHeight, horizontalScrollBarHeight = cachedHorizontalScrollBarHeight;
int previousVerticalScrollBarWidth, verticalScrollBarWidth = cachedVerticalScrollBarWidth;
int i = 0;
do {
previousViewWidth = viewWidth;
previousViewHeight = viewHeight;
previousHorizontalScrollBarHeight = horizontalScrollBarHeight;
previousVerticalScrollBarWidth = verticalScrollBarWidth;
if (view != null) {
if (constrainWidth && constrainHeight) {
viewWidth = Math.max
(width - rowHeaderWidth - verticalScrollBarWidth, 0);
viewHeight = Math.max
(height - columnHeaderHeight - horizontalScrollBarHeight, 0);
} else if (constrainWidth) {
viewWidth = Math.max
(width - rowHeaderWidth - verticalScrollBarWidth, 0);
viewHeight = view.getPreferredHeight(viewWidth);
} else if (constrainHeight) {
viewHeight = Math.max
(height - columnHeaderHeight - horizontalScrollBarHeight, 0);
viewWidth = view.getPreferredWidth(viewHeight);
} else {
Dimensions viewPreferredSize = view.getPreferredSize();
viewWidth = viewPreferredSize.width;
viewHeight = viewPreferredSize.height;
}
}
if (horizontalPolicy == ScrollBarPolicy.ALWAYS
|| (horizontalPolicy == ScrollBarPolicy.AUTO
&& viewWidth > width - rowHeaderWidth - verticalScrollBarWidth)) {
horizontalScrollBarHeight = horizontalScrollBar.getPreferredHeight(-1);
} else {
horizontalScrollBarHeight = 0;
}
if (verticalPolicy == ScrollBarPolicy.ALWAYS
|| (verticalPolicy == ScrollBarPolicy.AUTO
&& viewHeight > height - columnHeaderHeight - horizontalScrollBarHeight)) {
verticalScrollBarWidth = verticalScrollBar.getPreferredWidth(-1);
} else {
verticalScrollBarWidth = 0;
}
if (++i > 4) {
// Infinite loop protection
System.err.println("Breaking out of potential infinite loop");
break;
}
} while (viewWidth != previousViewWidth
|| viewHeight != previousViewHeight
|| horizontalScrollBarHeight != previousHorizontalScrollBarHeight
|| verticalScrollBarWidth != previousVerticalScrollBarWidth);
int scrollTop = scrollPane.getScrollTop();
int scrollLeft = scrollPane.getScrollLeft();
if (view != null) {
view.setSize(viewWidth, viewHeight);
view.setLocation(rowHeaderWidth - scrollLeft, columnHeaderHeight - scrollTop);
}
if (columnHeader != null) {
columnHeader.setSize(viewWidth, columnHeaderHeight);
columnHeader.setLocation(rowHeaderWidth - scrollLeft, 0);
}
if (rowHeader != null) {
rowHeader.setSize(rowHeaderWidth, viewHeight);
rowHeader.setLocation(0, columnHeaderHeight - scrollTop);
}
if (horizontalScrollBarHeight > 0) {
horizontalScrollBar.setVisible(true);
int horizontalScrollBarWidth = Math.max
(width - rowHeaderWidth - verticalScrollBarWidth, 0);
horizontalScrollBar.setSize(horizontalScrollBarWidth,
horizontalScrollBarHeight);
horizontalScrollBar.setLocation(rowHeaderWidth,
height - horizontalScrollBarHeight);
} else {
horizontalScrollBar.setVisible(false);
}
if (verticalScrollBarWidth > 0) {
verticalScrollBar.setVisible(true);
int verticalScrollBarHeight = Math.max
(height - columnHeaderHeight - horizontalScrollBarHeight, 0);
verticalScrollBar.setSize(verticalScrollBarWidth,
verticalScrollBarHeight);
verticalScrollBar.setLocation(width - verticalScrollBarWidth,
columnHeaderHeight);
} else {
verticalScrollBar.setVisible(false);
}
// Handle corner components
if (columnHeaderHeight > 0
&& rowHeaderWidth > 0) {
if (corner != null) {
corner.setVisible(true);
corner.setSize(rowHeaderWidth, columnHeaderHeight);
corner.setLocation(0, 0);
topLeftCorner.setVisible(false);
} else {
topLeftCorner.setVisible(true);
topLeftCorner.setSize(rowHeaderWidth, columnHeaderHeight);
topLeftCorner.setLocation(0, 0);
}
} else {
if (corner != null) {
corner.setVisible(false);
}
topLeftCorner.setVisible(false);
}
if (rowHeaderWidth > 0
&& horizontalScrollBarHeight > 0) {
bottomLeftCorner.setVisible(true);
bottomLeftCorner.setSize(rowHeaderWidth, horizontalScrollBarHeight);
bottomLeftCorner.setLocation(0, height - horizontalScrollBarHeight);
} else {
bottomLeftCorner.setVisible(false);
}
if (verticalScrollBarWidth > 0
&& horizontalScrollBarHeight > 0) {
bottomRightCorner.setVisible(true);
bottomRightCorner.setSize(verticalScrollBarWidth, horizontalScrollBarHeight);
bottomRightCorner.setLocation(width - verticalScrollBarWidth,
height - horizontalScrollBarHeight);
} else {
bottomRightCorner.setVisible(false);
}
if (columnHeaderHeight > 0
&& verticalScrollBarWidth > 0) {
topRightCorner.setVisible(true);
topRightCorner.setSize(verticalScrollBarWidth, columnHeaderHeight);
topRightCorner.setLocation(width - verticalScrollBarWidth, 0);
} else {
topRightCorner.setVisible(false);
}
// Perform bounds checking on the scrollTop and scrollLeft values,
// and adjust them as necessary. Make sure to do this after we've laid
// everything out, since our ViewPortListener methods rely on valid
// sizes from our components.
int maxScrollTop = getMaxScrollTop();
if (scrollTop > maxScrollTop) {
scrollPane.setScrollTop(maxScrollTop);
}
int maxScrollLeft = getMaxScrollLeft();
if (scrollLeft > maxScrollLeft) {
scrollPane.setScrollLeft(maxScrollLeft);
}
// Adjust the structure of our scroll bars. Make sure to do this after
// we adjust the scrollTop and scrollLeft values; otherwise we might
// try to set structure values that are out of bounds.