/*******************************************************************************
* Copyright (c) 2000, 2007 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.swt.custom;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.*;
/**
* A ControlEditor is a manager for a Control that appears above a composite and
* tracks with the moving and resizing of that composite. It can be used to
* display one control above another control. This could be used when editing a
* control that does not have editing capabilities by using a text editor or for
* launching a dialog by placing a button above a control.
* <p>
* Here is an example of using a ControlEditor: <code><pre>
* Canvas canvas = new Canvas(shell, SWT.BORDER);
* canvas.setBounds(10, 10, 300, 300);
* Color color = new Color(null, 255, 0, 0);
* canvas.setBackground(color);
* ControlEditor editor = new ControlEditor (canvas);
* // The editor will be a button in the bottom right corner of the canvas.
* // When selected, it will launch a Color dialog that will change the background
* // of the canvas.
* Button button = new Button(canvas, SWT.PUSH);
* button.setText("Select Color...");
* button.addSelectionListener (new SelectionAdapter() {
* public void widgetSelected(SelectionEvent e) {
* ColorDialog dialog = new ColorDialog(shell);
* dialog.open();
* RGB rgb = dialog.getRGB();
* if (rgb != null) {
* if (color != null) color.dispose();
* color = new Color(null, rgb);
* canvas.setBackground(color);
* }
*
* }
* });
*
* editor.horizontalAlignment = SWT.RIGHT;
* editor.verticalAlignment = SWT.BOTTOM;
* editor.grabHorizontal = false;
* editor.grabVertical = false;
* Point size = button.computeSize(SWT.DEFAULT, SWT.DEFAULT);
* editor.minimumWidth = size.x;
* editor.minimumHeight = size.y;
* editor.setEditor (button);
* </pre></code>
*
* @since 1.0
*/
public class ControlEditor {
/**
* Specifies how the editor should be aligned relative to the control. Allowed
* values are SWT.LEFT, SWT.RIGHT and SWT.CENTER. The default value is
* SWT.CENTER.
*/
public int horizontalAlignment = SWT.CENTER;
/**
* Specifies whether the editor should be sized to use the entire width of the
* control. True means resize the editor to the same width as the cell. False
* means do not adjust the width of the editor. The default value is false.
*/
public boolean grabHorizontal = false;
/**
* Specifies the minimum width the editor can have. This is used in
* association with a true value of grabHorizontal. If the cell becomes
* smaller than the minimumWidth, the editor will not made smaller than the
* minimum width value. The default value is 0.
*/
public int minimumWidth = 0;
/**
* Specifies how the editor should be aligned relative to the control. Allowed
* values are SWT.TOP, SWT.BOTTOM and SWT.CENTER. The default value is
* SWT.CENTER.
*/
public int verticalAlignment = SWT.CENTER;
/**
* Specifies whether the editor should be sized to use the entire height of
* the control. True means resize the editor to the same height as the
* underlying control. False means do not adjust the height of the editor. The
* default value is false.
*/
public boolean grabVertical = false;
/**
* Specifies the minimum height the editor can have. This is used in
* association with a true value of grabVertical. If the control becomes
* smaller than the minimumHeight, the editor will not made smaller than the
* minimum height value. The default value is 0.
*/
public int minimumHeight = 0;
Composite parent;
Control editor;
private boolean hadFocus;
private Listener controlListener;
private Listener scrollbarListener;
private final static int[] EVENTS = {/*
* SWT.KeyDown, SWT.KeyUp, SWT.MouseDown,
* SWT.MouseUp,
*/
SWT.Resize
};
/**
* Creates a ControlEditor for the specified Composite.
*
* @param parent the Composite above which this editor will be displayed
*/
public ControlEditor( Composite parent ) {
this.parent = parent;
controlListener = new Listener() {
public void handleEvent( Event e ) {
layout();
}
};
for( int i = 0; i < EVENTS.length; i++ ) {
parent.addListener( EVENTS[ i ], controlListener );
}
// TODO: [if] Remove instance check when ScrollBars are moved to Scrollable
if( parent instanceof Table ) {
Table table = ( Table )parent;
scrollbarListener = new Listener() {
public void handleEvent( Event e ) {
scroll( e );
}
};
ScrollBar hBar = table.getHorizontalBar();
if( hBar != null ) {
hBar.addListener( SWT.Selection, scrollbarListener );
}
ScrollBar vBar = table.getVerticalBar();
if( vBar != null ) {
vBar.addListener( SWT.Selection, scrollbarListener );
}
}
}
Rectangle computeBounds() {
Rectangle clientArea = parent.getClientArea();
Rectangle editorRect = new Rectangle( clientArea.x,
clientArea.y,
minimumWidth,
minimumHeight );
if( grabHorizontal )
editorRect.width = Math.max( clientArea.width, minimumWidth );
if( grabVertical )
editorRect.height = Math.max( clientArea.height, minimumHeight );
switch( horizontalAlignment ) {
case SWT.RIGHT:
editorRect.x += clientArea.width - editorRect.width;
break;
case SWT.LEFT:
// do nothing - clientArea.x is the right answer
break;
default:
// default is CENTER
editorRect.x += ( clientArea.width - editorRect.width ) / 2;
}
switch( verticalAlignment ) {
case SWT.BOTTOM:
editorRect.y += clientArea.height - editorRect.height;
break;
case SWT.TOP:
// do nothing - clientArea.y is the right answer
break;
default:
// default is CENTER
editorRect.y += ( clientArea.height - editorRect.height ) / 2;
}
return editorRect;
}
/**
* Removes all associations between the Editor and the underlying composite.
* The composite and the editor Control are <b>not</b> disposed.
*/
public void dispose() {
if( parent != null && !parent.isDisposed() ) {
for( int i = 0; i < EVENTS.length; i++ ) {
parent.removeListener( EVENTS[ i ], controlListener );
}
// TODO: [if] Remove instance check when ScrollBars are moved to Scrollable
if( parent instanceof Table ) {
Table table = ( Table )parent;
ScrollBar hBar = table.getHorizontalBar();
if( hBar != null ) {
hBar.removeListener( SWT.Selection, scrollbarListener );
}
ScrollBar vBar = table.getVerticalBar();
if( vBar != null ) {
vBar.removeListener( SWT.Selection, scrollbarListener );
}
}
}
parent = null;
editor = null;
hadFocus = false;
controlListener = null;
scrollbarListener = null;
}
/**
* Returns the Control that is displayed above the composite being edited.
*
* @return the Control that is displayed above the composite being edited
*/
public Control getEditor() {
return editor;
}
/**
* Lays out the control within the underlying composite. This method should be
* called after changing one or more fields to force the Editor to resize.
*/
public void layout() {
if( editor == null || editor.isDisposed() )
return;
if( editor.getVisible() ) {
hadFocus = editor.isFocusControl();
} // this doesn't work because
// resizing the column takes the focus away
// before we get here
editor.setBounds( computeBounds() );
if( hadFocus ) {
if( editor == null || editor.isDisposed() )
return;
editor.setFocus();
}
}
void scroll( Event e ) {
if( editor == null || editor.isDisposed() )
return;
layout();
}
/**
* Specify the Control that is to be displayed.
* <p>
* Note: The Control provided as the editor <b>must</b> be created with its
* parent being the Composite specified in the ControlEditor constructor.
*
* @param editor the Control that is displayed above the composite being
* edited
*/
public void setEditor( Control editor ) {
if( editor == null ) {
// this is the case where the caller is setting the editor to be blank
// set all the values accordingly
this.editor = null;
return;
}
this.editor = editor;
layout();
if( this.editor == null || this.editor.isDisposed() )
return;
editor.setVisible( true );
}
}