/*******************************************************************************
 * Copyright (c) 2000, 2006 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
 *******************************************************************************/
module dwt.custom;


import dwt.*;
import dwt.graphics.*;
import dwt.widgets.*;

/**
 * This Layout stacks all the controls one on top of the other and resizes all controls
 * to have the same size and location.
 * The control specified in topControl is visible and all other controls are not visible.
 * Users must set the topControl value to flip between the visible items and then call 
 * layout() on the composite which has the StackLayout.
 * 
 * <p> Here is an example which places ten buttons in a stack layout and 
 * flips between them:
 * 
 * <pre><code>
 *  public static void main(String[] args) {
 *      Display display = new Display();
 *      Shell shell = new Shell(display);
 *      shell.setLayout(new GridLayout());
 *  
 *      final Composite parent = new Composite(shell, DWT.NONE);
 *      parent.setLayoutData(new GridData(GridData.FILL_BOTH));
 *      final StackLayout layout = new StackLayout();
 *      parent.setLayout(layout);
 *      final Button[] bArray = new Button[10];
 *      for (int i = 0; i &lt; 10; i++) {
 *          bArray[i] = new Button(parent, DWT.PUSH);
 *          bArray[i].setText("Button "+i);
 *      }
 *      layout.topControl = bArray[0];
 *  
 *      Button b = new Button(shell, DWT.PUSH);
 *      b.setText("Show Next Button");
 *      final int[] index = new int[1];
 *      b.addListener(DWT.Selection, new Listener(){
 *          public void handleEvent(Event e) {
 *              index[0] = (index[0] + 1) % 10;
 *              layout.topControl = bArray[index[0]];
 *              parent.layout();
 *          }
 *      });
 *  
 *      shell.open();
 *      while (shell !is null && !shell.isDisposed()) {
 *          if (!display.readAndDispatch())
 *              display.sleep(); 
 *      }   
 *  }
 * </code></pre>
 */

public class StackLayout : Layout {
    
    /**
     * marginWidth specifies the number of pixels of horizontal margin
     * that will be placed along the left and right edges of the layout.
     *
     * The default value is 0.
     */
    public int marginWidth = 0;
    /**
     * marginHeight specifies the number of pixels of vertical margin
     * that will be placed along the top and bottom edges of the layout.
     *
     * The default value is 0.
     */
    public int marginHeight = 0;

    /**
     * topControl the Control that is displayed at the top of the stack.
     * All other controls that are children of the parent composite will not be visible.
     */
    public Control topControl;

protected Point computeSize(Composite composite, int wHint, int hHint, bool flushCache) {
    Control children[] = composite.getChildren();
    int maxWidth = 0;
    int maxHeight = 0;
    for (int i = 0; i < children.length; i++) {
        Point size = children[i].computeSize(wHint, hHint, flushCache);
        maxWidth = Math.max(size.x, maxWidth);
        maxHeight = Math.max(size.y, maxHeight);
    }
    int width = maxWidth + 2 * marginWidth;
    int height = maxHeight + 2 * marginHeight;
    if (wHint !is DWT.DEFAULT) width = wHint;
    if (hHint !is DWT.DEFAULT) height = hHint;
    return new Point(width, height);
}

protected bool flushCache(Control control) {
    return true;
}

protected void layout(Composite composite, bool flushCache) {
    Control children[] = composite.getChildren();
    Rectangle rect = composite.getClientArea();
    rect.x += marginWidth;
    rect.y += marginHeight;
    rect.width -= 2 * marginWidth;
    rect.height -= 2 * marginHeight;
    for (int i = 0; i < children.length; i++) {
        children[i].setBounds(rect);
        children[i].setVisible(children[i] is topControl);
            
    }
}

String getName () {
    String String = getClass ().getName ();
    int index = String.lastIndexOf ('.');
    if (index is -1) return String;
    return String.substring (index + 1, String.length ());
}

/**
 * Returns a String containing a concise, human-readable
 * description of the receiver.
 *
 * @return a String representation of the layout
 */
public String toString () {
    String String = getName ()+" {";
    if (marginWidth !is 0) String += "marginWidth="+marginWidth+" ";
    if (marginHeight !is 0) String += "marginHeight="+marginHeight+" ";
    if (topControl !is null) String += "topControl="+topControl+" ";
    String = String.trim();
    String += "}";
    return String;
}
}