| /* ScrollPane.java -- Scrolling window |
| Copyright (C) 1999, 2002, 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.awt; |
| |
| import java.awt.event.MouseEvent; |
| import java.awt.peer.ComponentPeer; |
| import java.awt.peer.ScrollPanePeer; |
| |
| import javax.accessibility.Accessible; |
| import javax.accessibility.AccessibleContext; |
| import javax.accessibility.AccessibleRole; |
| |
| /** |
| * This widget provides a scrollable region that allows a single |
| * subcomponent to be viewed through a smaller window. |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| */ |
| public class ScrollPane extends Container implements Accessible |
| { |
| |
| /* |
| * Static Variables |
| */ |
| |
| /** |
| * Constant indicating that scrollbars are created as needed in this |
| * windows. |
| */ |
| public static final int SCROLLBARS_AS_NEEDED = 0; |
| |
| /** |
| * Constant indicating that scrollbars are always displayed in this |
| * window. |
| */ |
| public static final int SCROLLBARS_ALWAYS = 1; |
| |
| /** |
| * Constant indicating that scrollbars are never displayed in this window. |
| */ |
| public static final int SCROLLBARS_NEVER = 2; |
| |
| // Serialization constant |
| private static final long serialVersionUID = 7956609840827222915L; |
| |
| /*************************************************************************/ |
| |
| /* |
| * Instance Variables |
| */ |
| |
| /** |
| * @serial The horizontal scrollbar for this window. The methods |
| * <code>setMinimum()</code>, <code>setMaximum</code>, and |
| * <code>setVisibleAmount</code> must not be called on this scrollbar. |
| */ |
| private ScrollPaneAdjustable hAdjustable; |
| |
| /** |
| * @serial The vertical scrollbar for this window. The methods |
| * <code>setMinimum()</code>, <code>setMaximum</code>, and |
| * <code>setVisibleAmount</code> must not be called on this scrollbar. |
| */ |
| private ScrollPaneAdjustable vAdjustable; |
| |
| /** |
| * @serial Indicates when scrollbars are displayed in this window, will |
| * be one of the constants from this class. |
| */ |
| private int scrollbarDisplayPolicy; |
| |
| // Current scroll position |
| private Point scrollPosition = new Point(0, 0); |
| |
| private boolean wheelScrollingEnabled; |
| |
| /*************************************************************************/ |
| |
| /* |
| * Constructors |
| */ |
| |
| /** |
| * Initializes a new instance of <code>ScrollPane</code> with a default |
| * scrollbar policy of <code>SCROLLBARS_AS_NEEDED</code>. |
| * |
| * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true. |
| */ |
| public |
| ScrollPane() |
| { |
| this(SCROLLBARS_AS_NEEDED); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Initializes a new instance of <code>ScrollPane</code> with the |
| * specified scrollbar policy. |
| * |
| * @param scrollbarDisplayPolicy When to display scrollbars, which must |
| * be one of the constants defined in this class. |
| * |
| * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true. |
| */ |
| public |
| ScrollPane(int scrollbarDisplayPolicy) |
| { |
| if (GraphicsEnvironment.isHeadless ()) |
| throw new HeadlessException (); |
| |
| this.scrollbarDisplayPolicy = scrollbarDisplayPolicy; |
| |
| if (scrollbarDisplayPolicy != SCROLLBARS_ALWAYS |
| && scrollbarDisplayPolicy != SCROLLBARS_AS_NEEDED |
| && scrollbarDisplayPolicy != SCROLLBARS_NEVER) |
| throw new IllegalArgumentException("Bad scrollbarDisplayPolicy: " + |
| scrollbarDisplayPolicy); |
| |
| if (scrollbarDisplayPolicy != SCROLLBARS_NEVER) |
| { |
| hAdjustable = new ScrollPaneAdjustable (this, Scrollbar.HORIZONTAL); |
| vAdjustable = new ScrollPaneAdjustable (this, Scrollbar.VERTICAL); |
| } |
| |
| wheelScrollingEnabled = true; |
| |
| // Default size. |
| setSize(100,100); |
| } |
| |
| /*************************************************************************/ |
| |
| /* |
| * Instance Variables |
| */ |
| |
| /** |
| * Returns the current scrollbar display policy. |
| * |
| * @return The current scrollbar display policy. |
| */ |
| public int |
| getScrollbarDisplayPolicy() |
| { |
| return(scrollbarDisplayPolicy); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Returns the horizontal scrollbar for this object. If the scrollbar |
| * display policy is set to <code>SCROLLBARS_NEVER</code> then this |
| * will be <code>null</code>. |
| * |
| * @return The horizontal scrollbar for this window. |
| */ |
| public Adjustable |
| getHAdjustable() |
| { |
| return(hAdjustable); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Returns the vertical scrollbar for this object. If the scrollbar |
| * display policy is set to <code>SCROLLBARS_NEVER</code> then this |
| * will be <code>null</code>. |
| * |
| * @return The horizontal scrollbar for this window. |
| */ |
| public Adjustable |
| getVAdjustable() |
| { |
| return(vAdjustable); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Returns the current viewport size. The viewport is the region of |
| * this object's window where the child is actually displayed. |
| * |
| * @return The viewport size. |
| */ |
| public Dimension getViewportSize () |
| { |
| Dimension viewsize = getSize (); |
| Insets insets = getInsets (); |
| |
| viewsize.width -= (insets.left + insets.right); |
| viewsize.height -= (insets.top + insets.bottom); |
| |
| Component[] list = getComponents(); |
| if ((list == null) || (list.length <= 0)) |
| return viewsize; |
| |
| Dimension dim = list[0].getPreferredSize(); |
| |
| if (dim.width <= 0 && dim.height <= 0) |
| return viewsize; |
| |
| int vScrollbarWidth = getVScrollbarWidth (); |
| int hScrollbarHeight = getHScrollbarHeight (); |
| |
| if (scrollbarDisplayPolicy == SCROLLBARS_ALWAYS) |
| { |
| viewsize.width -= vScrollbarWidth; |
| viewsize.height -= hScrollbarHeight; |
| return viewsize; |
| } |
| |
| if (scrollbarDisplayPolicy == SCROLLBARS_NEVER) |
| return viewsize; |
| |
| // The scroll policy is SCROLLBARS_AS_NEEDED, so we need to see if |
| // either scrollbar is needed. |
| |
| // Assume we don't need either scrollbar. |
| boolean mayNeedVertical = false; |
| boolean mayNeedHorizontal = false; |
| |
| boolean needVertical = false; |
| boolean needHorizontal = false; |
| |
| // Check if we need vertical scrollbars. If we do, then we need to |
| // subtract the width of the vertical scrollbar from the viewport's |
| // width. |
| if (dim.height > viewsize.height) |
| needVertical = true; |
| else if (dim.height > (viewsize.height - hScrollbarHeight)) |
| // This is tricky. In this case the child is tall enough that its |
| // bottom edge would be covered by a horizontal scrollbar, if one |
| // were present. This means that if there's a horizontal |
| // scrollbar then we need a vertical scrollbar. |
| mayNeedVertical = true; |
| |
| if (dim.width > viewsize.width) |
| needHorizontal = true; |
| else if (dim.width > (viewsize.width - vScrollbarWidth)) |
| mayNeedHorizontal = true; |
| |
| if (needVertical && mayNeedHorizontal) |
| needHorizontal = true; |
| |
| if (needHorizontal && mayNeedVertical) |
| needVertical = true; |
| |
| if (needHorizontal) |
| viewsize.height -= hScrollbarHeight; |
| |
| if (needVertical) |
| viewsize.width -= vScrollbarWidth; |
| |
| return viewsize; |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Returns the height of a horizontal scrollbar. |
| * |
| * @return The height of a horizontal scrollbar. |
| */ |
| public int |
| getHScrollbarHeight() |
| { |
| ScrollPanePeer spp = (ScrollPanePeer)getPeer(); |
| if (spp != null) |
| return(spp.getHScrollbarHeight()); |
| else |
| return(0); // FIXME: What to do here? |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Returns the width of a vertical scrollbar. |
| * |
| * @return The width of a vertical scrollbar. |
| */ |
| public int |
| getVScrollbarWidth() |
| { |
| ScrollPanePeer spp = (ScrollPanePeer)getPeer(); |
| if (spp != null) |
| return(spp.getVScrollbarWidth()); |
| else |
| return(0); // FIXME: What to do here? |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Returns the current scroll position of the viewport. |
| * |
| * @return The current scroll position of the viewport. |
| */ |
| public Point |
| getScrollPosition() |
| { |
| int x = 0; |
| int y = 0; |
| |
| Adjustable v = getVAdjustable(); |
| Adjustable h = getHAdjustable(); |
| |
| if (v != null) |
| y = v.getValue(); |
| if (h != null) |
| x = h.getValue(); |
| |
| return(new Point(x, y)); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Sets the scroll position to the specified value. |
| * |
| * @param scrollPosition The new scrollPosition. |
| * |
| * @exception IllegalArgumentException If the specified value is outside |
| * the legal scrolling range. |
| */ |
| public void |
| setScrollPosition(Point scrollPosition) throws IllegalArgumentException |
| { |
| setScrollPosition(scrollPosition.x, scrollPosition.y); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Sets the scroll position to the specified value. |
| * |
| * @param x The new X coordinate of the scroll position. |
| * @param y The new Y coordinate of the scroll position. |
| * |
| * @exception IllegalArgumentException If the specified value is outside |
| * the legal scrolling range. |
| */ |
| public void |
| setScrollPosition(int x, int y) |
| { |
| Adjustable h = getHAdjustable(); |
| Adjustable v = getVAdjustable(); |
| |
| if (h != null) |
| h.setValue(x); |
| if (v != null) |
| v.setValue(y); |
| |
| ScrollPanePeer spp = (ScrollPanePeer)getPeer(); |
| if (spp != null) |
| spp.setScrollPosition(x, y); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Notifies this object that it should create its native peer. |
| */ |
| public void |
| addNotify() |
| { |
| if (!isDisplayable ()) |
| return; |
| |
| setPeer((ComponentPeer)getToolkit().createScrollPane(this)); |
| super.addNotify(); |
| |
| Component[] list = getComponents(); |
| if (list != null && list.length > 0 && ! (list[0] instanceof Panel)) |
| { |
| Panel panel = new Panel(); |
| panel.setLayout(new BorderLayout()); |
| panel.add(list[0], BorderLayout.CENTER); |
| add(panel); |
| } |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Notifies this object that it should destroy its native peers. |
| */ |
| public void |
| removeNotify() |
| { |
| super.removeNotify(); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Adds the specified child component to this container. A |
| * <code>ScrollPane</code> can have at most one child, so if a second |
| * one is added, then first one is removed. |
| * |
| * @param component The component to add to this container. |
| * @param constraints A list of layout constraints for this object. |
| * @param index The index at which to add the child, which is ignored |
| * in this implementation. |
| */ |
| protected final void addImpl (Component component, Object constraints, |
| int index) |
| { |
| Component[] list = getComponents(); |
| if ((list != null) && (list.length > 0)) |
| remove(list[0]); |
| |
| super.addImpl(component, constraints, -1); |
| |
| doLayout(); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Lays out this component. This consists of resizing the sole child |
| * component to its perferred size. |
| */ |
| public void |
| doLayout() |
| { |
| layout (); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Lays out this component. This consists of resizing the sole child |
| * component to its perferred size. |
| * |
| * @deprecated This method is deprecated in favor of |
| * <code>doLayout()</code>. |
| */ |
| public void |
| layout() |
| { |
| Component[] list = getComponents (); |
| if ((list != null) && (list.length > 0)) |
| { |
| Dimension dim = list[0].getPreferredSize (); |
| Dimension vp = getViewportSize (); |
| |
| if (dim.width < vp.width) |
| dim.width = vp.width; |
| |
| if (dim.height < vp.height) |
| dim.height = vp.height; |
| |
| ScrollPanePeer peer = (ScrollPanePeer) getPeer (); |
| if (peer != null) |
| peer.childResized (dim.width, dim.height); |
| |
| list[0].setSize (dim); |
| |
| Point p = getScrollPosition (); |
| if (p.x > dim.width) |
| p.x = dim.width; |
| if (p.y > dim.height) |
| p.y = dim.height; |
| |
| setScrollPosition (p); |
| } |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method overrides its superclass method to ensure no layout |
| * manager is set for this container. <code>ScrollPane</code>'s do |
| * not have layout managers. |
| * |
| * @param layoutManager Ignored |
| */ |
| public final void |
| setLayout(LayoutManager layoutManager) |
| { |
| return; |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Prints all of the components in this container. |
| * |
| * @param graphics The desired graphics context for printing. |
| */ |
| public void |
| printComponents(Graphics graphics) |
| { |
| super.printComponents(graphics); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * Returns a debug string for this object. |
| * |
| * @return A debug string for this object. |
| */ |
| public String |
| paramString() |
| { |
| Insets insets = getInsets(); |
| return getName() + "," |
| + getX() + "," |
| + getY() + "," |
| + getWidth() + "x" + getHeight() + "," |
| + "ScrollPosition=(" + scrollPosition.getX() + "," |
| + scrollPosition.getY() + ")," |
| + "Insets=(" + insets.top + "," |
| + insets.left + "," |
| + insets.bottom + "," |
| + insets.right + ")," |
| + "ScrollbarDisplayPolicy=" + getScrollbarDisplayPolicy() + "," |
| + "wheelScrollingEnabled=" + isWheelScrollingEnabled(); |
| } |
| |
| /** |
| * Tells whether or not an event is enabled. |
| * |
| * @since 1.4 |
| */ |
| protected boolean eventTypeEnabled (int type) |
| { |
| if (type == MouseEvent.MOUSE_WHEEL) |
| return wheelScrollingEnabled; |
| |
| return super.eventTypeEnabled (type); |
| } |
| |
| /** |
| * Tells whether or not wheel scrolling is enabled. |
| * |
| * @since 1.4 |
| */ |
| public boolean isWheelScrollingEnabled () |
| { |
| return wheelScrollingEnabled; |
| } |
| |
| /** |
| * Enables/disables wheel scrolling. |
| * |
| * @since 1.4 |
| */ |
| public void setWheelScrollingEnabled (boolean enable) |
| { |
| wheelScrollingEnabled = enable; |
| } |
| |
| protected class AccessibleAWTScrollPane extends AccessibleAWTContainer |
| { |
| public AccessibleRole getAccessibleRole() |
| { |
| return AccessibleRole.SCROLL_PANE; |
| } |
| } |
| |
| /** |
| * Gets the AccessibleContext associated with this <code>ScrollPane</code>. |
| * The context is created, if necessary. |
| * |
| * @return the associated context |
| */ |
| public AccessibleContext getAccessibleContext() |
| { |
| /* Create the context if this is the first request */ |
| if (accessibleContext == null) |
| accessibleContext = new AccessibleAWTScrollPane(); |
| return accessibleContext; |
| } |
| } // class ScrollPane |
| |