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package org.eclipse.swt.custom;
/*
* Licensed Materials - Property of IBM,
* (c) Copyright IBM Corp. 1998, 2001 All Rights Reserved
*/
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
/*
* A ScrolledComposite provides scrollbars and will scroll its content when the user
* uses the scrollbars.
*
* <p>If the ScrolledComposite can be configured to stretch the content to be as big as the
* ScrolledComposite when the composite is resized to a size larger than the minimum width
* or minimum height and to provide scrolls when the ScrolledComposite is smaller than the
* minimum width and minimum height. Refer to the methods setExpandHorizontal,
* setExpandVertical, setMinWidth and setMinHeight.
*
* <p>
* <dl>
* <dt><b>Styles:</b><dd>H_SCROLL, V_SCROLL
* </dl>
*/
public class ScrolledComposite extends Composite {
private Control content;
private Listener contentListener;
private int minHeight = 0;
private int minWidth = 0;
private boolean expandHorizontal = false;
private boolean expandVertical = false;
public ScrolledComposite(Composite parent, int style) {
super(parent, checkStyle(style));
ScrollBar hBar = getHorizontalBar ();
if (hBar != null) {
hBar.addListener (SWT.Selection, new Listener () {
public void handleEvent (Event e) {
hScroll();
}
});
}
ScrollBar vBar = getVerticalBar ();
if (vBar != null) {
vBar.addListener (SWT.Selection, new Listener () {
public void handleEvent (Event e) {
vScroll();
}
});
}
addListener (SWT.Resize, new Listener () {
public void handleEvent (Event e) {
resize();
}
});
contentListener = new Listener() {
public void handleEvent(Event e) {
if (e.type != SWT.Resize) return;
resize();
}
};
}
private static int checkStyle (int style) {
int mask = SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER;
return style & mask;
}
/**
* Get the content that is being scrolled.
*/
public Control getContent() {
return content;
}
private void hScroll() {
if (content == null) return;
Point location = content.getLocation ();
ScrollBar hBar = getHorizontalBar ();
int hSelection = hBar.getSelection ();
content.setLocation (-hSelection, location.y);
}
private void resize() {
if (content == null) return;
Rectangle contentRect = content.getBounds();
Rectangle hostRect = getClientArea();
if (expandHorizontal) {
contentRect.width = Math.max(minWidth, hostRect.width);
}
if (expandVertical) {
contentRect.height = Math.max(minHeight, hostRect.height);
}
ScrollBar hBar = getHorizontalBar ();
if (hBar != null) {
hBar.setMaximum (contentRect.width);
hBar.setThumb (Math.min (contentRect.width, hostRect.width));
int hPage = contentRect.width - hostRect.width;
int hSelection = hBar.getSelection ();
if (hSelection >= hPage) {
if (hPage <= 0) hSelection = 0;
contentRect.x = -hSelection;
}
}
ScrollBar vBar = getVerticalBar ();
if (vBar != null) {
vBar.setMaximum (contentRect.height);
vBar.setThumb (Math.min (contentRect.height, hostRect.height));
int vPage = contentRect.height - hostRect.height;
int vSelection = vBar.getSelection ();
if (vSelection >= vPage) {
if (vPage <= 0) vSelection = 0;
contentRect.y = -vSelection;
}
}
content.setBounds (contentRect);
}
/**
* Set the content that will be scrolled.
*/
public void setContent(Control content) {
if (this.content != null && !this.content.isDisposed()) {
this.content.removeListener(SWT.Resize, contentListener);
content.setBounds(new Rectangle(-200, -200, 0, 0));
}
this.content = content;
if (this.content != null) {
this.content.addListener(SWT.Resize, contentListener);
resize();
}
}
/**
* Configure the ScrolledComposite to resize the content object to be as wide as the
* ScrolledComposite when the width of the ScrolledComposite is greater than the
* minimum width specified in setMinWidth. If the ScrolledComposite is less than the
* minimum width, the content will not resized and instead the horizontal scroll bar will be
* used to view the entire width.
* If expand is false, this behaviour is turned off. By default, this behaviour is turned off.
*/
public void setExpandHorizontal(boolean expand) {
if (expand == expandHorizontal) return;
expandHorizontal = expand;
resize();
}
/**
* Configure the ScrolledComposite to resize the content object to be as tall as the
* ScrolledComposite when the height of the ScrolledComposite is greater than the
* minimum height specified in setMinHeight. If the ScrolledComposite is less than the
* minimum height, the content will not resized and instead the vertical scroll bar will be
* used to view the entire height.
* If expand is false, this behaviour is turned off. By default, this behaviour is turned off.
*/
public void setExpandVertical(boolean expand) {
if (expand == expandVertical) return;
expandVertical = expand;
resize();
}
public void setLayout (Layout layout) {
// do not allow a layout to be set on this class because layout is being handled by the resize listener
return;
}
/**
* Specify the minimum height at which the ScrolledComposite will begin scrolling the
* content with the vertical scroll bar. This value is only relevant if
* setExpandVertical(true) has been set.
*/
public void setMinHeight(int height) {
if (height == minHeight) return;
minHeight = Math.max(0, height);
resize();
}
/**
* Specify the minimum width at which the ScrolledComposite will begin scrolling the
* content with the horizontal scroll bar. This value is only relevant if
* setExpandHorizontal(true) has been set.
*/
public void setMinWidth(int width) {
if (width == minWidth) return;
minWidth = Math.max(0, width);
resize();
}
private void vScroll() {
Control[] children = getChildren();
if (children.length == 0) return;
Control content = children[0];
Point location = content.getLocation ();
ScrollBar vBar = getVerticalBar ();
int vSelection = vBar.getSelection ();
content.setLocation (location.x, -vSelection);
}
}
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