/*******************************************************************************
* Copyright (c) 2002, 2015 Innoopract Informationssysteme GmbH 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:
* Innoopract Informationssysteme GmbH - initial API and implementation
* EclipseSource - ongoing development
******************************************************************************/
package org.eclipse.swt.widgets;
import org.eclipse.rap.rwt.theme.BoxDimensions;
import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.graphics.Rectangle;
/**
* This class is the abstract superclass of all classes which
* represent controls that have standard scroll bars.
* <dl>
* <dt><b>Styles:</b></dt>
* <dd>H_SCROLL, V_SCROLL</dd>
* <dt><b>Events:</b>
* <dd>(none)</dd>
* </dl>
* <p>
* IMPORTANT: This class is intended to be subclassed <em>only</em>
* within the SWT implementation.
* </p>
* @since 1.0
*/
public abstract class Scrollable extends Control {
ScrollBar verticalBar;
ScrollBar horizontalBar;
Scrollable( Composite parent ) {
// prevent instantiation from outside this package
super( parent );
}
/**
* Constructs a new instance of this class given its parent
* and a style value describing its behavior and appearance.
* <p>
* The style value is either one of the style constants defined in
* class <code>SWT</code> which is applicable to instances of this
* class, or must be built by <em>bitwise OR</em>'ing together
* (that is, using the <code>int</code> "|" operator) two or more
* of those <code>SWT</code> style constants. The class description
* lists the style constants that are applicable to the class.
* Style bits are also inherited from superclasses.
* </p>
*
* @param parent a composite control which will be the parent of the new instance (cannot be null)
* @param style the style of control to construct
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
* </ul>
* @exception SWTException <ul>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
* <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
* </ul>
*
* @see SWT#H_SCROLL
* @see SWT#V_SCROLL
* @see Widget#checkSubclass
* @see Widget#getStyle
*/
public Scrollable( Composite parent, int style ) {
super( parent, style );
createScrollBars();
}
private void createScrollBars() {
if( ( style & SWT.H_SCROLL ) != 0 ) {
horizontalBar = new ScrollBar( this, SWT.H_SCROLL );
horizontalBar.setVisible( false );
}
if( ( style & SWT.V_SCROLL ) != 0 ) {
verticalBar = new ScrollBar( this, SWT.V_SCROLL );
verticalBar.setVisible( false );
}
}
/**
* Returns a rectangle which describes the area of the
* receiver which is capable of displaying data (that is,
* not covered by the "trimmings").
*
* @return the client area
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @see #computeTrim
*/
public Rectangle getClientArea() {
checkWidget();
Rectangle bounds = getBounds();
BoxDimensions border = getBorder();
BoxDimensions padding = getPadding();
int width = bounds.width
- ( border.left + border.right )
- ( padding.left + padding.right )
- getVScrollBarWidth();
int height = bounds.height
- ( border.top + border.bottom )
- ( padding.top + padding.bottom )
- getHScrollBarHeight();
return new Rectangle( padding.left, padding.top, Math.max( 0, width ), Math.max( 0, height ) );
}
/**
* Given a desired <em>client area</em> for the receiver
* (as described by the arguments), returns the bounding
* rectangle which would be required to produce that client
* area.
* <p>
* In other words, it returns a rectangle such that, if the
* receiver's bounds were set to that rectangle, the area
* of the receiver which is capable of displaying data
* (that is, not covered by the "trimmings") would be the
* rectangle described by the arguments (relative to the
* receiver's parent).
* </p>
*
* @param x the desired x coordinate of the client area
* @param y the desired y coordinate of the client area
* @param width the desired width of the client area
* @param height the desired height of the client area
* @return the required bounds to produce the given client area
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @see #getClientArea
*/
public Rectangle computeTrim( int x, int y, int width, int height ) {
checkWidget();
BoxDimensions border = getBorder();
BoxDimensions padding = getPadding();
int newWidth = width + border.left + border.right + padding.left + padding.right;
if( verticalBar != null ) {
newWidth += verticalBar.getSize().x;
}
int newHeight = height + border.top + border.bottom + padding.top + padding.bottom;
if( horizontalBar != null ) {
newHeight += horizontalBar.getSize().y;
}
int newX = x - border.left - padding.left;
int newY = y - border.top - padding.top;
return new Rectangle( newX, newY, newWidth, newHeight );
}
/**
* Returns the receiver's horizontal scroll bar if it has
* one, and null if it does not.
*
* @return the horizontal scroll bar (or null)
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @since 1.4
*/
public ScrollBar getHorizontalBar() {
checkWidget();
return horizontalBar;
}
/**
* Returns the receiver's vertical scroll bar if it has
* one, and null if it does not.
*
* @return the vertical scroll bar (or null)
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @since 1.4
*/
public ScrollBar getVerticalBar() {
checkWidget();
return verticalBar;
}
@Override
void releaseChildren() {
super.releaseChildren();
if( verticalBar != null ) {
verticalBar.dispose();
}
if( horizontalBar != null ) {
horizontalBar.dispose();
}
}
int getVScrollBarWidth() {
int result = 0;
if( verticalBar != null && verticalBar.getVisible() ) {
result = verticalBar.getSize().x;
}
return result;
}
int getHScrollBarHeight() {
int result = 0;
if( horizontalBar != null && horizontalBar.getVisible() ) {
result = horizontalBar.getSize().y;
}
return result;
}
}