Java example source code file (BasicScrollPaneUI.java)
The BasicScrollPaneUI.java Java example source code/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package javax.swing.plaf.basic;
import sun.swing.DefaultLookup;
import sun.swing.UIAction;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.plaf.*;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;
import java.awt.Component;
import java.awt.Rectangle;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Insets;
import java.awt.Graphics;
import java.awt.event.*;
/**
* A default L&F implementation of ScrollPaneUI.
*
* @author Hans Muller
*/
public class BasicScrollPaneUI
extends ScrollPaneUI implements ScrollPaneConstants
{
protected JScrollPane scrollpane;
protected ChangeListener vsbChangeListener;
protected ChangeListener hsbChangeListener;
protected ChangeListener viewportChangeListener;
protected PropertyChangeListener spPropertyChangeListener;
private MouseWheelListener mouseScrollListener;
private int oldExtent = Integer.MIN_VALUE;
/**
* PropertyChangeListener installed on the vertical scrollbar.
*/
private PropertyChangeListener vsbPropertyChangeListener;
/**
* PropertyChangeListener installed on the horizontal scrollbar.
*/
private PropertyChangeListener hsbPropertyChangeListener;
private Handler handler;
/**
* State flag that shows whether setValue() was called from a user program
* before the value of "extent" was set in right-to-left component
* orientation.
*/
private boolean setValueCalled = false;
public static ComponentUI createUI(JComponent x) {
return new BasicScrollPaneUI();
}
static void loadActionMap(LazyActionMap map) {
map.put(new Actions(Actions.SCROLL_UP));
map.put(new Actions(Actions.SCROLL_DOWN));
map.put(new Actions(Actions.SCROLL_HOME));
map.put(new Actions(Actions.SCROLL_END));
map.put(new Actions(Actions.UNIT_SCROLL_UP));
map.put(new Actions(Actions.UNIT_SCROLL_DOWN));
map.put(new Actions(Actions.SCROLL_LEFT));
map.put(new Actions(Actions.SCROLL_RIGHT));
map.put(new Actions(Actions.UNIT_SCROLL_RIGHT));
map.put(new Actions(Actions.UNIT_SCROLL_LEFT));
}
public void paint(Graphics g, JComponent c) {
Border vpBorder = scrollpane.getViewportBorder();
if (vpBorder != null) {
Rectangle r = scrollpane.getViewportBorderBounds();
vpBorder.paintBorder(scrollpane, g, r.x, r.y, r.width, r.height);
}
}
/**
* @return new Dimension(Short.MAX_VALUE, Short.MAX_VALUE)
*/
public Dimension getMaximumSize(JComponent c) {
return new Dimension(Short.MAX_VALUE, Short.MAX_VALUE);
}
protected void installDefaults(JScrollPane scrollpane)
{
LookAndFeel.installBorder(scrollpane, "ScrollPane.border");
LookAndFeel.installColorsAndFont(scrollpane,
"ScrollPane.background",
"ScrollPane.foreground",
"ScrollPane.font");
Border vpBorder = scrollpane.getViewportBorder();
if ((vpBorder == null) ||( vpBorder instanceof UIResource)) {
vpBorder = UIManager.getBorder("ScrollPane.viewportBorder");
scrollpane.setViewportBorder(vpBorder);
}
LookAndFeel.installProperty(scrollpane, "opaque", Boolean.TRUE);
}
protected void installListeners(JScrollPane c)
{
vsbChangeListener = createVSBChangeListener();
vsbPropertyChangeListener = createVSBPropertyChangeListener();
hsbChangeListener = createHSBChangeListener();
hsbPropertyChangeListener = createHSBPropertyChangeListener();
viewportChangeListener = createViewportChangeListener();
spPropertyChangeListener = createPropertyChangeListener();
JViewport viewport = scrollpane.getViewport();
JScrollBar vsb = scrollpane.getVerticalScrollBar();
JScrollBar hsb = scrollpane.getHorizontalScrollBar();
if (viewport != null) {
viewport.addChangeListener(viewportChangeListener);
}
if (vsb != null) {
vsb.getModel().addChangeListener(vsbChangeListener);
vsb.addPropertyChangeListener(vsbPropertyChangeListener);
}
if (hsb != null) {
hsb.getModel().addChangeListener(hsbChangeListener);
hsb.addPropertyChangeListener(hsbPropertyChangeListener);
}
scrollpane.addPropertyChangeListener(spPropertyChangeListener);
mouseScrollListener = createMouseWheelListener();
scrollpane.addMouseWheelListener(mouseScrollListener);
}
protected void installKeyboardActions(JScrollPane c) {
InputMap inputMap = getInputMap(JComponent.
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
SwingUtilities.replaceUIInputMap(c, JComponent.
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, inputMap);
LazyActionMap.installLazyActionMap(c, BasicScrollPaneUI.class,
"ScrollPane.actionMap");
}
InputMap getInputMap(int condition) {
if (condition == JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT) {
InputMap keyMap = (InputMap)DefaultLookup.get(scrollpane, this,
"ScrollPane.ancestorInputMap");
InputMap rtlKeyMap;
if (scrollpane.getComponentOrientation().isLeftToRight() ||
((rtlKeyMap = (InputMap)DefaultLookup.get(scrollpane, this,
"ScrollPane.ancestorInputMap.RightToLeft")) == null)) {
return keyMap;
} else {
rtlKeyMap.setParent(keyMap);
return rtlKeyMap;
}
}
return null;
}
public void installUI(JComponent x) {
scrollpane = (JScrollPane)x;
installDefaults(scrollpane);
installListeners(scrollpane);
installKeyboardActions(scrollpane);
}
protected void uninstallDefaults(JScrollPane c) {
LookAndFeel.uninstallBorder(scrollpane);
if (scrollpane.getViewportBorder() instanceof UIResource) {
scrollpane.setViewportBorder(null);
}
}
protected void uninstallListeners(JComponent c) {
JViewport viewport = scrollpane.getViewport();
JScrollBar vsb = scrollpane.getVerticalScrollBar();
JScrollBar hsb = scrollpane.getHorizontalScrollBar();
if (viewport != null) {
viewport.removeChangeListener(viewportChangeListener);
}
if (vsb != null) {
vsb.getModel().removeChangeListener(vsbChangeListener);
vsb.removePropertyChangeListener(vsbPropertyChangeListener);
}
if (hsb != null) {
hsb.getModel().removeChangeListener(hsbChangeListener);
hsb.removePropertyChangeListener(hsbPropertyChangeListener);
}
scrollpane.removePropertyChangeListener(spPropertyChangeListener);
if (mouseScrollListener != null) {
scrollpane.removeMouseWheelListener(mouseScrollListener);
}
vsbChangeListener = null;
hsbChangeListener = null;
viewportChangeListener = null;
spPropertyChangeListener = null;
mouseScrollListener = null;
handler = null;
}
protected void uninstallKeyboardActions(JScrollPane c) {
SwingUtilities.replaceUIActionMap(c, null);
SwingUtilities.replaceUIInputMap(c, JComponent.
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, null);
}
public void uninstallUI(JComponent c) {
uninstallDefaults(scrollpane);
uninstallListeners(scrollpane);
uninstallKeyboardActions(scrollpane);
scrollpane = null;
}
private Handler getHandler() {
if (handler == null) {
handler = new Handler();
}
return handler;
}
protected void syncScrollPaneWithViewport()
{
JViewport viewport = scrollpane.getViewport();
JScrollBar vsb = scrollpane.getVerticalScrollBar();
JScrollBar hsb = scrollpane.getHorizontalScrollBar();
JViewport rowHead = scrollpane.getRowHeader();
JViewport colHead = scrollpane.getColumnHeader();
boolean ltr = scrollpane.getComponentOrientation().isLeftToRight();
if (viewport != null) {
Dimension extentSize = viewport.getExtentSize();
Dimension viewSize = viewport.getViewSize();
Point viewPosition = viewport.getViewPosition();
if (vsb != null) {
int extent = extentSize.height;
int max = viewSize.height;
int value = Math.max(0, Math.min(viewPosition.y, max - extent));
vsb.setValues(value, extent, 0, max);
}
if (hsb != null) {
int extent = extentSize.width;
int max = viewSize.width;
int value;
if (ltr) {
value = Math.max(0, Math.min(viewPosition.x, max - extent));
} else {
int currentValue = hsb.getValue();
/* Use a particular formula to calculate "value"
* until effective x coordinate is calculated.
*/
if (setValueCalled && ((max - currentValue) == viewPosition.x)) {
value = Math.max(0, Math.min(max - extent, currentValue));
/* After "extent" is set, turn setValueCalled flag off.
*/
if (extent != 0) {
setValueCalled = false;
}
} else {
if (extent > max) {
viewPosition.x = max - extent;
viewport.setViewPosition(viewPosition);
value = 0;
} else {
/* The following line can't handle a small value of
* viewPosition.x like Integer.MIN_VALUE correctly
* because (max - extent - viewPositoiin.x) causes
* an overflow. As a result, value becomes zero.
* (e.g. setViewPosition(Integer.MAX_VALUE, ...)
* in a user program causes a overflow.
* Its expected value is (max - extent).)
* However, this seems a trivial bug and adding a
* fix makes this often-called method slow, so I'll
* leave it until someone claims.
*/
value = Math.max(0, Math.min(max - extent, max - extent - viewPosition.x));
if (oldExtent > extent) {
value -= oldExtent - extent;
}
}
}
}
oldExtent = extent;
hsb.setValues(value, extent, 0, max);
}
if (rowHead != null) {
Point p = rowHead.getViewPosition();
p.y = viewport.getViewPosition().y;
p.x = 0;
rowHead.setViewPosition(p);
}
if (colHead != null) {
Point p = colHead.getViewPosition();
if (ltr) {
p.x = viewport.getViewPosition().x;
} else {
p.x = Math.max(0, viewport.getViewPosition().x);
}
p.y = 0;
colHead.setViewPosition(p);
}
}
}
/**
* Returns the baseline.
*
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @see javax.swing.JComponent#getBaseline(int, int)
* @since 1.6
*/
public int getBaseline(JComponent c, int width, int height) {
if (c == null) {
throw new NullPointerException("Component must be non-null");
}
if (width < 0 || height < 0) {
throw new IllegalArgumentException("Width and height must be >= 0");
}
JViewport viewport = scrollpane.getViewport();
Insets spInsets = scrollpane.getInsets();
int y = spInsets.top;
height = height - spInsets.top - spInsets.bottom;
width = width - spInsets.left - spInsets.right;
JViewport columnHeader = scrollpane.getColumnHeader();
if (columnHeader != null && columnHeader.isVisible()) {
Component header = columnHeader.getView();
if (header != null && header.isVisible()) {
// Header is always given it's preferred size.
Dimension headerPref = header.getPreferredSize();
int baseline = header.getBaseline(headerPref.width,
headerPref.height);
if (baseline >= 0) {
return y + baseline;
}
}
Dimension columnPref = columnHeader.getPreferredSize();
height -= columnPref.height;
y += columnPref.height;
}
Component view = (viewport == null) ? null : viewport.getView();
if (view != null && view.isVisible() &&
view.getBaselineResizeBehavior() ==
Component.BaselineResizeBehavior.CONSTANT_ASCENT) {
Border viewportBorder = scrollpane.getViewportBorder();
if (viewportBorder != null) {
Insets vpbInsets = viewportBorder.getBorderInsets(scrollpane);
y += vpbInsets.top;
height = height - vpbInsets.top - vpbInsets.bottom;
width = width - vpbInsets.left - vpbInsets.right;
}
if (view.getWidth() > 0 && view.getHeight() > 0) {
Dimension min = view.getMinimumSize();
width = Math.max(min.width, view.getWidth());
height = Math.max(min.height, view.getHeight());
}
if (width > 0 && height > 0) {
int baseline = view.getBaseline(width, height);
if (baseline > 0) {
return y + baseline;
}
}
}
return -1;
}
/**
* Returns an enum indicating how the baseline of the component
* changes as the size changes.
*
* @throws NullPointerException {@inheritDoc}
* @see javax.swing.JComponent#getBaseline(int, int)
* @since 1.6
*/
public Component.BaselineResizeBehavior getBaselineResizeBehavior(
JComponent c) {
super.getBaselineResizeBehavior(c);
// Baseline is either from the header, in which case it's always
// the same size and therefor can be created as CONSTANT_ASCENT.
// If the header doesn't have a baseline than the baseline will only
// be valid if it's BaselineResizeBehavior is
// CONSTANT_ASCENT, so, return CONSTANT_ASCENT.
return Component.BaselineResizeBehavior.CONSTANT_ASCENT;
}
/**
* Listener for viewport events.
*/
public class ViewportChangeHandler implements ChangeListener
{
// NOTE: This class exists only for backward compatibility. All
// its functionality has been moved into Handler. If you need to add
// new functionality add it to the Handler, but make sure this
// class calls into the Handler.
public void stateChanged(ChangeEvent e) {
getHandler().stateChanged(e);
}
}
protected ChangeListener createViewportChangeListener() {
return getHandler();
}
/**
* Horizontal scrollbar listener.
*/
public class HSBChangeListener implements ChangeListener
{
// NOTE: This class exists only for backward compatibility. All
// its functionality has been moved into Handler. If you need to add
// new functionality add it to the Handler, but make sure this
// class calls into the Handler.
public void stateChanged(ChangeEvent e)
{
getHandler().stateChanged(e);
}
}
/**
* Returns a <code>PropertyChangeListener that will be installed
* on the horizontal <code>JScrollBar.
*/
private PropertyChangeListener createHSBPropertyChangeListener() {
return getHandler();
}
protected ChangeListener createHSBChangeListener() {
return getHandler();
}
/**
* Vertical scrollbar listener.
*/
public class VSBChangeListener implements ChangeListener
{
// NOTE: This class exists only for backward compatibility. All
// its functionality has been moved into Handler. If you need to add
// new functionality add it to the Handler, but make sure this
// class calls into the Handler.
public void stateChanged(ChangeEvent e)
{
getHandler().stateChanged(e);
}
}
/**
* Returns a <code>PropertyChangeListener that will be installed
* on the vertical <code>JScrollBar.
*/
private PropertyChangeListener createVSBPropertyChangeListener() {
return getHandler();
}
protected ChangeListener createVSBChangeListener() {
return getHandler();
}
/**
* MouseWheelHandler is an inner class which implements the
* MouseWheelListener interface. MouseWheelHandler responds to
* MouseWheelEvents by scrolling the JScrollPane appropriately.
* If the scroll pane's
* <code>isWheelScrollingEnabled
* method returns false, no scrolling occurs.
*
* @see javax.swing.JScrollPane#isWheelScrollingEnabled
* @see #createMouseWheelListener
* @see java.awt.event.MouseWheelListener
* @see java.awt.event.MouseWheelEvent
* @since 1.4
*/
protected class MouseWheelHandler implements MouseWheelListener {
// NOTE: This class exists only for backward compatibility. All
// its functionality has been moved into Handler. If you need to add
// new functionality add it to the Handler, but make sure this
// class calls into the Handler.
/**
* Called when the mouse wheel is rotated while over a
* JScrollPane.
*
* @param e MouseWheelEvent to be handled
* @since 1.4
*/
public void mouseWheelMoved(MouseWheelEvent e) {
getHandler().mouseWheelMoved(e);
}
}
/**
* Creates an instance of MouseWheelListener, which is added to the
* JScrollPane by installUI(). The returned MouseWheelListener is used
* to handle mouse wheel-driven scrolling.
*
* @return MouseWheelListener which implements wheel-driven scrolling
* @see #installUI
* @see MouseWheelHandler
* @since 1.4
*/
protected MouseWheelListener createMouseWheelListener() {
return getHandler();
}
protected void updateScrollBarDisplayPolicy(PropertyChangeEvent e) {
scrollpane.revalidate();
scrollpane.repaint();
}
protected void updateViewport(PropertyChangeEvent e)
{
JViewport oldViewport = (JViewport)(e.getOldValue());
JViewport newViewport = (JViewport)(e.getNewValue());
if (oldViewport != null) {
oldViewport.removeChangeListener(viewportChangeListener);
}
if (newViewport != null) {
Point p = newViewport.getViewPosition();
if (scrollpane.getComponentOrientation().isLeftToRight()) {
p.x = Math.max(p.x, 0);
} else {
int max = newViewport.getViewSize().width;
int extent = newViewport.getExtentSize().width;
if (extent > max) {
p.x = max - extent;
} else {
p.x = Math.max(0, Math.min(max - extent, p.x));
}
}
p.y = Math.max(p.y, 0);
newViewport.setViewPosition(p);
newViewport.addChangeListener(viewportChangeListener);
}
}
protected void updateRowHeader(PropertyChangeEvent e)
{
JViewport newRowHead = (JViewport)(e.getNewValue());
if (newRowHead != null) {
JViewport viewport = scrollpane.getViewport();
Point p = newRowHead.getViewPosition();
p.y = (viewport != null) ? viewport.getViewPosition().y : 0;
newRowHead.setViewPosition(p);
}
}
protected void updateColumnHeader(PropertyChangeEvent e)
{
JViewport newColHead = (JViewport)(e.getNewValue());
if (newColHead != null) {
JViewport viewport = scrollpane.getViewport();
Point p = newColHead.getViewPosition();
if (viewport == null) {
p.x = 0;
} else {
if (scrollpane.getComponentOrientation().isLeftToRight()) {
p.x = viewport.getViewPosition().x;
} else {
p.x = Math.max(0, viewport.getViewPosition().x);
}
}
newColHead.setViewPosition(p);
scrollpane.add(newColHead, COLUMN_HEADER);
}
}
private void updateHorizontalScrollBar(PropertyChangeEvent pce) {
updateScrollBar(pce, hsbChangeListener, hsbPropertyChangeListener);
}
private void updateVerticalScrollBar(PropertyChangeEvent pce) {
updateScrollBar(pce, vsbChangeListener, vsbPropertyChangeListener);
}
private void updateScrollBar(PropertyChangeEvent pce, ChangeListener cl,
PropertyChangeListener pcl) {
JScrollBar sb = (JScrollBar)pce.getOldValue();
if (sb != null) {
if (cl != null) {
sb.getModel().removeChangeListener(cl);
}
if (pcl != null) {
sb.removePropertyChangeListener(pcl);
}
}
sb = (JScrollBar)pce.getNewValue();
if (sb != null) {
if (cl != null) {
sb.getModel().addChangeListener(cl);
}
if (pcl != null) {
sb.addPropertyChangeListener(pcl);
}
}
}
public class PropertyChangeHandler implements PropertyChangeListener
{
// NOTE: This class exists only for backward compatibility. All
// its functionality has been moved into Handler. If you need to add
// new functionality add it to the Handler, but make sure this
// class calls into the Handler.
public void propertyChange(PropertyChangeEvent e)
{
getHandler().propertyChange(e);
}
}
/**
* Creates an instance of PropertyChangeListener that's added to
* the JScrollPane by installUI(). Subclasses can override this method
* to return a custom PropertyChangeListener, e.g.
* <pre>
* class MyScrollPaneUI extends BasicScrollPaneUI {
* protected PropertyChangeListener <b>createPropertyChangeListener() {
* return new MyPropertyChangeListener();
* }
* public class MyPropertyChangeListener extends PropertyChangeListener {
* public void propertyChange(PropertyChangeEvent e) {
* if (e.getPropertyName().equals("viewport")) {
* // do some extra work when the viewport changes
* }
* super.propertyChange(e);
* }
* }
* }
* </pre>
*
* @see java.beans.PropertyChangeListener
* @see #installUI
*/
protected PropertyChangeListener createPropertyChangeListener() {
return getHandler();
}
private static class Actions extends UIAction {
private static final String SCROLL_UP = "scrollUp";
private static final String SCROLL_DOWN = "scrollDown";
private static final String SCROLL_HOME = "scrollHome";
private static final String SCROLL_END = "scrollEnd";
private static final String UNIT_SCROLL_UP = "unitScrollUp";
private static final String UNIT_SCROLL_DOWN = "unitScrollDown";
private static final String SCROLL_LEFT = "scrollLeft";
private static final String SCROLL_RIGHT = "scrollRight";
private static final String UNIT_SCROLL_LEFT = "unitScrollLeft";
private static final String UNIT_SCROLL_RIGHT = "unitScrollRight";
Actions(String key) {
super(key);
}
public void actionPerformed(ActionEvent e) {
JScrollPane scrollPane = (JScrollPane)e.getSource();
boolean ltr = scrollPane.getComponentOrientation().isLeftToRight();
String key = getName();
if (key == SCROLL_UP) {
scroll(scrollPane, SwingConstants.VERTICAL, -1, true);
}
else if (key == SCROLL_DOWN) {
scroll(scrollPane, SwingConstants.VERTICAL, 1, true);
}
else if (key == SCROLL_HOME) {
scrollHome(scrollPane);
}
else if (key == SCROLL_END) {
scrollEnd(scrollPane);
}
else if (key == UNIT_SCROLL_UP) {
scroll(scrollPane, SwingConstants.VERTICAL, -1, false);
}
else if (key == UNIT_SCROLL_DOWN) {
scroll(scrollPane, SwingConstants.VERTICAL, 1, false);
}
else if (key == SCROLL_LEFT) {
scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? -1 : 1,
true);
}
else if (key == SCROLL_RIGHT) {
scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? 1 : -1,
true);
}
else if (key == UNIT_SCROLL_LEFT) {
scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? -1 : 1,
false);
}
else if (key == UNIT_SCROLL_RIGHT) {
scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? 1 : -1,
false);
}
}
private void scrollEnd(JScrollPane scrollpane) {
JViewport vp = scrollpane.getViewport();
Component view;
if (vp != null && (view = vp.getView()) != null) {
Rectangle visRect = vp.getViewRect();
Rectangle bounds = view.getBounds();
if (scrollpane.getComponentOrientation().isLeftToRight()) {
vp.setViewPosition(new Point(bounds.width - visRect.width,
bounds.height - visRect.height));
} else {
vp.setViewPosition(new Point(0,
bounds.height - visRect.height));
}
}
}
private void scrollHome(JScrollPane scrollpane) {
JViewport vp = scrollpane.getViewport();
Component view;
if (vp != null && (view = vp.getView()) != null) {
if (scrollpane.getComponentOrientation().isLeftToRight()) {
vp.setViewPosition(new Point(0, 0));
} else {
Rectangle visRect = vp.getViewRect();
Rectangle bounds = view.getBounds();
vp.setViewPosition(new Point(bounds.width - visRect.width, 0));
}
}
}
private void scroll(JScrollPane scrollpane, int orientation,
int direction, boolean block) {
JViewport vp = scrollpane.getViewport();
Component view;
if (vp != null && (view = vp.getView()) != null) {
Rectangle visRect = vp.getViewRect();
Dimension vSize = view.getSize();
int amount;
if (view instanceof Scrollable) {
if (block) {
amount = ((Scrollable)view).getScrollableBlockIncrement
(visRect, orientation, direction);
}
else {
amount = ((Scrollable)view).getScrollableUnitIncrement
(visRect, orientation, direction);
}
}
else {
if (block) {
if (orientation == SwingConstants.VERTICAL) {
amount = visRect.height;
}
else {
amount = visRect.width;
}
}
else {
amount = 10;
}
}
if (orientation == SwingConstants.VERTICAL) {
visRect.y += (amount * direction);
if ((visRect.y + visRect.height) > vSize.height) {
visRect.y = Math.max(0, vSize.height - visRect.height);
}
else if (visRect.y < 0) {
visRect.y = 0;
}
}
else {
if (scrollpane.getComponentOrientation().isLeftToRight()) {
visRect.x += (amount * direction);
if ((visRect.x + visRect.width) > vSize.width) {
visRect.x = Math.max(0, vSize.width - visRect.width);
} else if (visRect.x < 0) {
visRect.x = 0;
}
} else {
visRect.x -= (amount * direction);
if (visRect.width > vSize.width) {
visRect.x = vSize.width - visRect.width;
} else {
visRect.x = Math.max(0, Math.min(vSize.width - visRect.width, visRect.x));
}
}
}
vp.setViewPosition(visRect.getLocation());
}
}
}
class Handler implements ChangeListener, PropertyChangeListener, MouseWheelListener {
//
// MouseWheelListener
//
public void mouseWheelMoved(MouseWheelEvent e) {
if (scrollpane.isWheelScrollingEnabled() &&
e.getWheelRotation() != 0) {
JScrollBar toScroll = scrollpane.getVerticalScrollBar();
int direction = e.getWheelRotation() < 0 ? -1 : 1;
int orientation = SwingConstants.VERTICAL;
// find which scrollbar to scroll, or return if none
if (toScroll == null || !toScroll.isVisible()) {
toScroll = scrollpane.getHorizontalScrollBar();
if (toScroll == null || !toScroll.isVisible()) {
return;
}
orientation = SwingConstants.HORIZONTAL;
}
e.consume();
if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {
JViewport vp = scrollpane.getViewport();
if (vp == null) { return; }
Component comp = vp.getView();
int units = Math.abs(e.getUnitsToScroll());
// When the scrolling speed is set to maximum, it's possible
// for a single wheel click to scroll by more units than
// will fit in the visible area. This makes it
// hard/impossible to get to certain parts of the scrolling
// Component with the wheel. To make for more accurate
// low-speed scrolling, we limit scrolling to the block
// increment if the wheel was only rotated one click.
boolean limitScroll = Math.abs(e.getWheelRotation()) == 1;
// Check if we should use the visibleRect trick
Object fastWheelScroll = toScroll.getClientProperty(
"JScrollBar.fastWheelScrolling");
if (Boolean.TRUE == fastWheelScroll &&
comp instanceof Scrollable) {
// 5078454: Under maximum acceleration, we may scroll
// by many 100s of units in ~1 second.
//
// BasicScrollBarUI.scrollByUnits() can bog down the EDT
// with repaints in this situation. However, the
// Scrollable interface allows us to pass in an
// arbitrary visibleRect. This allows us to accurately
// calculate the total scroll amount, and then update
// the GUI once. This technique provides much faster
// accelerated wheel scrolling.
Scrollable scrollComp = (Scrollable) comp;
Rectangle viewRect = vp.getViewRect();
int startingX = viewRect.x;
boolean leftToRight =
comp.getComponentOrientation().isLeftToRight();
int scrollMin = toScroll.getMinimum();
int scrollMax = toScroll.getMaximum() -
toScroll.getModel().getExtent();
if (limitScroll) {
int blockIncr =
scrollComp.getScrollableBlockIncrement(viewRect,
orientation,
direction);
if (direction < 0) {
scrollMin = Math.max(scrollMin,
toScroll.getValue() - blockIncr);
}
else {
scrollMax = Math.min(scrollMax,
toScroll.getValue() + blockIncr);
}
}
for (int i = 0; i < units; i++) {
int unitIncr =
scrollComp.getScrollableUnitIncrement(viewRect,
orientation, direction);
// Modify the visible rect for the next unit, and
// check to see if we're at the end already.
if (orientation == SwingConstants.VERTICAL) {
if (direction < 0) {
viewRect.y -= unitIncr;
if (viewRect.y <= scrollMin) {
viewRect.y = scrollMin;
break;
}
}
else { // (direction > 0
viewRect.y += unitIncr;
if (viewRect.y >= scrollMax) {
viewRect.y = scrollMax;
break;
}
}
}
else {
// Scroll left
if ((leftToRight && direction < 0) ||
(!leftToRight && direction > 0)) {
viewRect.x -= unitIncr;
if (leftToRight) {
if (viewRect.x < scrollMin) {
viewRect.x = scrollMin;
break;
}
}
}
// Scroll right
else if ((leftToRight && direction > 0) ||
(!leftToRight && direction < 0)) {
viewRect.x += unitIncr;
if (leftToRight) {
if (viewRect.x > scrollMax) {
viewRect.x = scrollMax;
break;
}
}
}
else {
assert false : "Non-sensical ComponentOrientation / scroll direction";
}
}
}
// Set the final view position on the ScrollBar
if (orientation == SwingConstants.VERTICAL) {
toScroll.setValue(viewRect.y);
}
else {
if (leftToRight) {
toScroll.setValue(viewRect.x);
}
else {
// rightToLeft scrollbars are oriented with
// minValue on the right and maxValue on the
// left.
int newPos = toScroll.getValue() -
(viewRect.x - startingX);
if (newPos < scrollMin) {
newPos = scrollMin;
}
else if (newPos > scrollMax) {
newPos = scrollMax;
}
toScroll.setValue(newPos);
}
}
}
else {
// Viewport's view is not a Scrollable, or fast wheel
// scrolling is not enabled.
BasicScrollBarUI.scrollByUnits(toScroll, direction,
units, limitScroll);
}
}
else if (e.getScrollType() ==
MouseWheelEvent.WHEEL_BLOCK_SCROLL) {
BasicScrollBarUI.scrollByBlock(toScroll, direction);
}
}
}
//
// ChangeListener: This is added to the vieport, and hsb/vsb models.
//
public void stateChanged(ChangeEvent e) {
JViewport viewport = scrollpane.getViewport();
if (viewport != null) {
if (e.getSource() == viewport) {
syncScrollPaneWithViewport();
}
else {
JScrollBar hsb = scrollpane.getHorizontalScrollBar();
if (hsb != null && e.getSource() == hsb.getModel()) {
hsbStateChanged(viewport, e);
}
else {
JScrollBar vsb = scrollpane.getVerticalScrollBar();
if (vsb != null && e.getSource() == vsb.getModel()) {
vsbStateChanged(viewport, e);
}
}
}
}
}
private void vsbStateChanged(JViewport viewport, ChangeEvent e) {
BoundedRangeModel model = (BoundedRangeModel)(e.getSource());
Point p = viewport.getViewPosition();
p.y = model.getValue();
viewport.setViewPosition(p);
}
private void hsbStateChanged(JViewport viewport, ChangeEvent e) {
BoundedRangeModel model = (BoundedRangeModel)(e.getSource());
Point p = viewport.getViewPosition();
int value = model.getValue();
if (scrollpane.getComponentOrientation().isLeftToRight()) {
p.x = value;
} else {
int max = viewport.getViewSize().width;
int extent = viewport.getExtentSize().width;
int oldX = p.x;
/* Set new X coordinate based on "value".
*/
p.x = max - extent - value;
/* If setValue() was called before "extent" was fixed,
* turn setValueCalled flag on.
*/
if ((extent == 0) && (value != 0) && (oldX == max)) {
setValueCalled = true;
} else {
/* When a pane without a horizontal scroll bar was
* reduced and the bar appeared, the viewport should
* show the right side of the view.
*/
if ((extent != 0) && (oldX < 0) && (p.x == 0)) {
p.x += value;
}
}
}
viewport.setViewPosition(p);
}
//
// PropertyChangeListener: This is installed on both the JScrollPane
// and the horizontal/vertical scrollbars.
//
// Listens for changes in the model property and reinstalls the
// horizontal/vertical PropertyChangeListeners.
public void propertyChange(PropertyChangeEvent e) {
if (e.getSource() == scrollpane) {
scrollPanePropertyChange(e);
}
else {
sbPropertyChange(e);
}
}
private void scrollPanePropertyChange(PropertyChangeEvent e) {
String propertyName = e.getPropertyName();
if (propertyName == "verticalScrollBarDisplayPolicy") {
updateScrollBarDisplayPolicy(e);
}
else if (propertyName == "horizontalScrollBarDisplayPolicy") {
updateScrollBarDisplayPolicy(e);
}
else if (propertyName == "viewport") {
updateViewport(e);
}
else if (propertyName == "rowHeader") {
updateRowHeader(e);
}
else if (propertyName == "columnHeader") {
updateColumnHeader(e);
}
else if (propertyName == "verticalScrollBar") {
updateVerticalScrollBar(e);
}
else if (propertyName == "horizontalScrollBar") {
updateHorizontalScrollBar(e);
}
else if (propertyName == "componentOrientation") {
scrollpane.revalidate();
scrollpane.repaint();
}
}
// PropertyChangeListener for the horizontal and vertical scrollbars.
private void sbPropertyChange(PropertyChangeEvent e) {
String propertyName = e.getPropertyName();
Object source = e.getSource();
if ("model" == propertyName) {
JScrollBar sb = scrollpane.getVerticalScrollBar();
BoundedRangeModel oldModel = (BoundedRangeModel)e.
getOldValue();
ChangeListener cl = null;
if (source == sb) {
cl = vsbChangeListener;
}
else if (source == scrollpane.getHorizontalScrollBar()) {
sb = scrollpane.getHorizontalScrollBar();
cl = hsbChangeListener;
}
if (cl != null) {
if (oldModel != null) {
oldModel.removeChangeListener(cl);
}
if (sb.getModel() != null) {
sb.getModel().addChangeListener(cl);
}
}
}
else if ("componentOrientation" == propertyName) {
if (source == scrollpane.getHorizontalScrollBar()) {
JScrollBar hsb = scrollpane.getHorizontalScrollBar();
JViewport viewport = scrollpane.getViewport();
Point p = viewport.getViewPosition();
if (scrollpane.getComponentOrientation().isLeftToRight()) {
p.x = hsb.getValue();
} else {
p.x = viewport.getViewSize().width - viewport.getExtentSize().width - hsb.getValue();
}
viewport.setViewPosition(p);
}
}
}
}
}
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