package com.foundation.view.swt.layout;

import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * A very simple layout that centers the first child within the parent.
 * All other children are not visible.
 * There is no data attached to the children that is used by this layout.
 */
public class CenterLayout extends Layout {
	private Point size = new Point(0, 0);
	private Point firstChildSize = new Point(0, 0);
/**
 * CenterLayout constructor.
 */
public CenterLayout() {
}//CenterLayout()//
/* (non-Javadoc)
 * @see org.eclipse.swt.widgets.Layout#computeSize(org.eclipse.swt.widgets.Composite, int, int, boolean)
 */
protected Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache) {
	if(flushCache) {
		Control[] children = composite.getChildren();
		
		size.x = 0;
		size.y = 0;
		firstChildSize.x = 0;
		firstChildSize.y = 0;
		
		if(children != null) {
			for(int index = 0; index < children.length; index++) {
				Point childSize = children[index].computeSize(wHint, hHint, flushCache);
		
				size.x = Math.max(childSize.x, size.x);
				size.y = Math.max(childSize.y, size.y);
				
				if(index == 0) {
					firstChildSize.x = childSize.x;
					firstChildSize.y = childSize.y;
				}//if//
			}//for//
		}//if//
	}//if//
	
	return new Point(size.x, size.y);
}//computeSize()//
/* (non-Javadoc)
 * @see org.eclipse.swt.widgets.Layout#layout(org.eclipse.swt.widgets.Composite, boolean)
 */
protected void layout(Composite composite, boolean flushCache) {
	Rectangle space = composite.getClientArea();
	Control[] children = composite.getChildren();
	
	if(flushCache || firstChildSize.x == 0 || firstChildSize.y == 0) {
		if(children != null && children.length > 0) {
			Point childSize = children[0].computeSize(-1, -1, true);

			firstChildSize.x = childSize.x;
			firstChildSize.y = childSize.y;
		}//if//
		else {
			firstChildSize.x = 0;
			firstChildSize.y = 0;
		}//else//
	}//if//

	if(children != null) {
		for(int index = 0; index < children.length; index++) {
			if(index == 0) {
				children[index].setSize(firstChildSize);
				children[index].setLocation(space.x + ((space.width - firstChildSize.x) >> 1), space.y + ((space.height - firstChildSize.y) >> 1));
			}//if//
			else {
				children[index].setSize(0, 0);
				children[index].setLocation(0, 0);
			}//else//
		}//for//
	}//if//
}//layout()//
}//CenterLayout//