bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/misc/OverlayComposite.java

package org.eclipse.ui.internal.misc;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import org.eclipse.jface.resource.*;
import org.eclipse.swt.graphics.*;
import java.util.*;
/**
 *	Instances represent images that are composed by overlaying one or more
 *	stand-alone images directly on top of each other.
 */
public class OverlayComposite extends CompositeImageDescriptor {		
	private ImageData backgroundImage;
	private ImageData	leftImage;
	private ImageData	rightImage;
	private ImageData	topImage;
	private ImageData	bottomImage;

	private List foregroundImages = new ArrayList();
/**
 *	Create an instance of this class.
 */
public OverlayComposite(ImageData background) {
	backgroundImage = background;
}
/**
 *	Add the passed image to this descriptor's collection of images to 
 * be composed together to create an image.
 */
public void addForegroundImage(ImageData image) {
	foregroundImages.add(image);
}
/**
 *Superimpose self's images within the given bounds by means of #drawImage
 *
 *@see CompositeImage#drawImage(ImageData src,int ox,int oy)
 */
protected void drawCompositeImage(int width, int height) {
	//draw background
	drawImage(backgroundImage, getLeftBound(), getTopBound());

	//draw foreground images
	Iterator e = foregroundImages.iterator();
	while (e.hasNext())
		drawImage(((ImageData) e.next()), getLeftBound(), getTopBound());

	//draw extensions
	if (topImage != null)
		drawImage(topImage, getLeftBound(), 0);
	if (bottomImage != null)
		drawImage(bottomImage, getLeftBound(), height - bottomImage.height);
	if (leftImage != null)
		drawImage(leftImage, 0, getTopBound());
	if (rightImage != null)
		drawImage(rightImage, width - rightImage.width, getTopBound());

}
/**
 * @see Object#equals
 */
public boolean equals(Object o) {
	if (!(o instanceof OverlayComposite)) {
		return false;
	}
	OverlayComposite other = (OverlayComposite) o;

	return equals(backgroundImage, other.backgroundImage)
		&& equals(leftImage, other.leftImage)
		&& equals(rightImage, other.rightImage)
		&& equals(topImage, other.topImage)
		&& equals(bottomImage, other.bottomImage)
		&& equals(foregroundImages, other.foregroundImages);
}
/**
 * Private utility for comparing two possibly-null objects.
 */
private boolean equals(Object o1, Object o2) {
	return o1 == null ? o2 == null : o1.equals(o2);
}
/**
 *	Answer the left-most coordinate that the main image can draw to
 *
 *	@return int
 */
protected int getLeftBound() {
	if (leftImage == null)
		return 0;
		
	return leftImage.width;
}
/**
 *	Answer self's size, as determined by the size of the initially-
 *	provided base-level image
 */
protected Point getSize() {
	//start with basic size
	Point size = new Point(backgroundImage.width,backgroundImage.height);

	//overlays may increase size.
	if (topImage != null)
		size.y += topImage.height;

	if (bottomImage != null)
		size.y += bottomImage.height;

	if (leftImage != null)
		size.x += leftImage.width;

	if (rightImage != null)
		size.x += rightImage.width;

	return size;	
}
/**
 *	Answer the top-most coordinate that the main image can draw to
 *
 *	@return int
 */
protected int getTopBound() {
	if (topImage == null)
		return 0;
		
	return topImage.height;
}
/**
 * @see Object#hashCode
 */
public int hashCode() {
	return hashCode(backgroundImage)
		+ hashCode(leftImage)
		+ hashCode(rightImage)
		+ hashCode(topImage)
		+ hashCode(bottomImage)
		+ hashCode(foregroundImages);
}
/**
 * Private utility for getting the hashCode for an
 * object that may be null.
 */
private int hashCode(Object o) {
	return o == null ? 0 : o.hashCode();
}
/**
 *  Set the image to be drawn below the primary overlay region.
 */
public void setBottomExtension(ImageData value) {
	bottomImage = value;
}
/**
 *  Set the image to be drawn to the left of the primary overlay region.
 */
public void setLeftExtension(ImageData value) {
	leftImage = value;
}
/**
 *  Set the image to be drawn to the right of the primary overlay region.
 */
public void setRightExtension(ImageData value) {
	rightImage = value;
}
/**
 *  Set the image to be drawn above the primary overlay region.
 */
public void setTopExtension(ImageData value) {
	topImage = value;
}
}