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package org.pepsoft.util.swing;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Rectangle;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import javax.swing.JPanel;
import javax.swing.JScrollBar;
/**
* A container for a {@link TiledImageViewer}, which adds scrollbars around it.
* The scrollbars take the combined {@link TileProvider#getExtent() extents} of
* the tile providers into account, in that their sizes by default only allow
* scrolling inside the combined extent of the tile providers.
*
* <p>The image can be scrolled outside the extent by mouse dragging, or
* programmatically, and when done so the scrollbars will adjust dynamically.
*
* <p>If none of the tile providers have an extent, or there are no tile
* providers configured, the scrollbars will be disabled.
*
* @author pepijn
*/
public class TiledImageViewerContainer extends JPanel implements TiledImageViewer.ViewListener, AdjustmentListener {
public TiledImageViewerContainer(TiledImageViewer view) {
this.view = view;
setLayout(new GridBagLayout());
GridBagConstraints constraints = new GridBagConstraints();
constraints.weightx = 1.0f;
constraints.weighty = 1.0f;
constraints.fill = GridBagConstraints.BOTH;
add(view, constraints);
constraints.weightx = 0.0f;
constraints.gridwidth = GridBagConstraints.REMAINDER;
add(verticalScrollbar, constraints);
constraints.weightx = 1.0f;
constraints.weighty = 0.0f;
constraints.gridwidth = 1;
add(horizontalScrollbar, constraints);
horizontalScrollbar.addAdjustmentListener(this);
verticalScrollbar.addAdjustmentListener(this);
view.setViewListener(this);
}
/**
* When set to true, prevents the scrollbars from updating on view changed
* events. When set to false, updates the scrollbars immediately.
*
* @param inhibitUpdates Whether scrollbar updates should be inhibited.
*/
public void setInhibitUpdates(boolean inhibitUpdates) {
if (inhibitUpdates != this.inhibitUpdates) {
this.inhibitUpdates = inhibitUpdates;
if (! inhibitUpdates) {
programmaticChange = true;
try {
updateScrollBars();
} finally {
programmaticChange = false;
}
}
}
}
// ViewListener
@Override
public void viewChanged(TiledImageViewer source) {
if ((! programmaticChange) && (! inhibitUpdates)) {
programmaticChange = true;
try {
updateScrollBars();
} finally {
programmaticChange = false;
}
}
}
// AdjustmentListener
@Override
public void adjustmentValueChanged(AdjustmentEvent e) {
if (programmaticChange) {
return;
}
programmaticChange = true;
try {
if (e.getSource() == horizontalScrollbar) {
int dx = e.getValue() - previousHorizontalValue;
if (dx != 0) {
previousHorizontalValue = e.getValue();
view.moveBy(dx, 0);
if (! e.getValueIsAdjusting()) {
updateScrollBars();
}
}
} else if (e.getSource() == verticalScrollbar) {
int dy = e.getValue() - previousVerticalValue;
if (dy != 0) {
previousVerticalValue = e.getValue();
view.moveBy(0, dy);
if (! e.getValueIsAdjusting()) {
updateScrollBars();
}
}
}
} finally {
programmaticChange = false;
}
}
private void updateScrollBars() {
Rectangle viewExtent = view.getExtent();
if (viewExtent == null) {
// If there is no extent we can't meaningfully scroll, so disable
// the scrollbars
if (scrollingEnabled) {
horizontalScrollbar.setEnabled(false);
verticalScrollbar.setEnabled(false);
scrollingEnabled = false;
}
} else {
if (! scrollingEnabled) {
horizontalScrollbar.setEnabled(true);
verticalScrollbar.setEnabled(true);
scrollingEnabled = true;
}
// If the extent is smaller than the viewport, add a border to allow
// scrolling the extent to any edge of the viewport
int viewWidth = view.getWidth(), viewHeight = view.getHeight();
if (viewExtent.width < viewWidth) {
viewExtent.x -= (viewWidth - viewExtent.width);
viewExtent.width += (viewWidth - viewExtent.width) * 2;
}
if (viewExtent.height < viewHeight) {
viewExtent.y -= (viewHeight - viewExtent.height);
viewExtent.height += (viewHeight - viewExtent.height) * 2;
}
Rectangle viewBounds = new Rectangle(0, 0, viewWidth, viewHeight);
// The combined area is the total area which the scrollbars should
// cover:
Rectangle combinedArea = viewExtent.union(viewBounds);
horizontalScrollbar.setMinimum(combinedArea.x);
horizontalScrollbar.setMaximum(combinedArea.x + combinedArea.width);
horizontalScrollbar.setVisibleAmount(viewWidth);
horizontalScrollbar.setValue(0);
horizontalScrollbar.setBlockIncrement(viewWidth * 9 / 10);
previousHorizontalValue = 0;
verticalScrollbar.setMinimum(combinedArea.y);
verticalScrollbar.setMaximum(combinedArea.y + combinedArea.height);
verticalScrollbar.setVisibleAmount(viewHeight);
verticalScrollbar.setValue(0);
verticalScrollbar.setBlockIncrement(viewHeight * 9 / 10);
previousVerticalValue = 0;
}
}
private final TiledImageViewer view;
private final JScrollBar horizontalScrollbar = new JScrollBar(JScrollBar.HORIZONTAL), verticalScrollbar = new JScrollBar();
private int previousHorizontalValue, previousVerticalValue;
private boolean scrollingEnabled = true, programmaticChange, inhibitUpdates;
}