/*******************************************************************************
* Copyright (c) 2000, 2005 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.ui.forms.widgets;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.ScrolledComposite;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.ui.internal.forms.widgets.FormUtil;
/**
* This class is used to provide common scrolling services to a number of
* controls in the toolkit. Classes that extend it are not required to implement
* any method.
*
* @since 1.0
*/
public abstract class SharedScrolledComposite extends ScrolledComposite {
// private static final int H_SCROLL_INCREMENT = 5;
// private static final int V_SCROLL_INCREMENT = 64;
private boolean ignoreLayouts = true;
private boolean ignoreResizes = false;
private boolean expandHorizontal = false;
private boolean expandVertical = false;
private SizeCache contentCache = new SizeCache();
private boolean reflowPending = false;
private boolean delayedReflow = true;
/**
* Creates the new instance.
*
* @param parent
* the parent composite
* @param style
* the style to use
*/
public SharedScrolledComposite(Composite parent, int style) {
super(parent, style);
addListener(SWT.Resize, new Listener() {
public void handleEvent(Event e) {
if (!ignoreResizes) {
scheduleReflow(false);
}
}
});
initializeScrollBars();
}
/**
* Sets the foreground of the control and its content.
*
* @param fg
* the new foreground color
*/
public void setForeground(Color fg) {
super.setForeground(fg);
if (getContent() != null)
getContent().setForeground(fg);
}
/**
* Sets the background of the control and its content.
*
* @param bg
* the new background color
*/
public void setBackground(Color bg) {
super.setBackground(bg);
if (getContent() != null)
getContent().setBackground(bg);
}
/**
* Sets the font of the form. This font will be used to render the title
* text. It will not affect the body.
*/
public void setFont(Font font) {
super.setFont(font);
if (getContent() != null)
getContent().setFont(font);
}
/**
* Overrides 'super' to pass the proper colors and font
*/
public void setContent(Control content) {
super.setContent(content);
if (content != null) {
content.setForeground(getForeground());
content.setBackground(getBackground());
content.setFont(getFont());
}
}
/**
* If content is set, transfers focus to the content.
*/
public boolean setFocus() {
boolean result;
FormUtil.setFocusScrollingEnabled(this, false);
if (getContent() != null)
result = getContent().setFocus();
else
result = super.setFocus();
FormUtil.setFocusScrollingEnabled(this, true);
return result;
}
/*
* (non-Javadoc)
*
* @see org.eclipse.swt.widgets.Composite#layout(boolean)
*/
public void layout(boolean changed) {
if (ignoreLayouts) {
return;
}
ignoreLayouts = true;
ignoreResizes = true;
super.layout(changed);
ignoreResizes = false;
}
/*
* (non-Javadoc)
*
* @see org.eclipse.swt.custom.ScrolledComposite#setExpandHorizontal(boolean)
*/
public void setExpandHorizontal(boolean expand) {
expandHorizontal = expand;
super.setExpandHorizontal(expand);
}
/*
* (non-Javadoc)
*
* @see org.eclipse.swt.custom.ScrolledComposite#setExpandVertical(boolean)
*/
public void setExpandVertical(boolean expand) {
expandVertical = expand;
super.setExpandVertical(expand);
}
/**
* Recomputes the body layout and the scroll bars. The method should be used
* when changes somewhere in the form body invalidate the current layout
* and/or scroll bars.
*
* @param flushCache
* if <code>true</code>, drop the cached data
*/
public void reflow(boolean flushCache) {
Composite c = (Composite) getContent();
Rectangle clientArea = getClientArea();
if (c == null)
return;
contentCache.setControl(c);
if (flushCache) {
contentCache.flush();
}
setRedraw(false);
Point newSize = contentCache.computeSize(FormUtil.getWidthHint(
clientArea.width, c), FormUtil.getHeightHint(clientArea.height,
c));
// Point currentSize = c.getSize();
if (!(expandHorizontal && expandVertical)) {
c.setSize(newSize);
}
setMinSize(newSize);
FormUtil.updatePageIncrement(this);
ignoreLayouts = false;
layout(flushCache);
ignoreLayouts = true;
contentCache.layoutIfNecessary();
setRedraw(true);
}
private void updateSizeWhilePending() {
Control c = getContent();
Rectangle area = getClientArea();
setMinSize(area.width, c.getSize().y);
}
private void scheduleReflow(final boolean flushCache) {
if (delayedReflow) {
if (reflowPending) {
updateSizeWhilePending();
return;
}
getDisplay().asyncExec(new Runnable() {
public void run() {
if (!isDisposed())
reflow(flushCache);
reflowPending = false;
}
});
reflowPending = true;
} else
reflow(flushCache);
}
private void initializeScrollBars() {
ScrollBar hbar = getHorizontalBar();
if (hbar != null) {
// hbar.setIncrement(H_SCROLL_INCREMENT);
}
ScrollBar vbar = getVerticalBar();
if (vbar != null) {
// vbar.setIncrement(V_SCROLL_INCREMENT);
}
FormUtil.updatePageIncrement(this);
}
/**
* Tests if the control uses delayed reflow.
* @return <code>true</code> if reflow requests will
* be delayed, <code>false</code> otherwise.
*/
public boolean isDelayedReflow() {
return delayedReflow;
}
/**
* Sets the delayed reflow feature. When used,
* it will schedule a reflow on resize requests
* and reject subsequent reflows until the
* scheduled one is performed. This improves
* performance by
* @param delayedReflow
* The delayedReflow to set.
*/
public void setDelayedReflow(boolean delayedReflow) {
this.delayedReflow = delayedReflow;
}
}