Computing the "full bounding box" of a CCNode in Cocos2D. (Put this code in a CCNode subclass.)

gistfile1.m

/*!
 Return the -boundingBox of another node, converted into this node's local
 coordinate space.
 */
-(CGRect) boundingBoxConvertedToNodeSpace:(CCNode *)other
{
    // Get the bottomLeft and topRight corners of the other node's bounding box
    // in the other node's coordinate space.
    CGRect boundingBox = [other boundingBox];
    CGPoint bottomLeft = CGPointMake(boundingBox.origin.x, boundingBox.origin.y);
    CGPoint topRight = CGPointMake(boundingBox.origin.x + boundingBox.size.width, boundingBox.origin.y + boundingBox.size.height);
    
    // Convert bottomLeft and topRight to the global coordinate space.
    CGPoint worldSpaceBottomLeft = [other.parent convertToWorldSpace:bottomLeft];
    CGPoint worldSpaceTopRight = [other.parent convertToWorldSpace:topRight];
    
    // Convert worldSpaceBottomLeft and worldSpaceTopRight into this node's
    // local coordinate space.
    CGPoint nodeSpaceBottomLeft = [self.parent convertToNodeSpace:worldSpaceBottomLeft];
    CGPoint nodeSpaceTopRight = [self.parent convertToNodeSpace:worldSpaceTopRight];

    // Finally, construct the bounding box in this node's local coordinate space
    // and return it.
    float width = nodeSpaceTopRight.x - nodeSpaceBottomLeft.x;
    float height = nodeSpaceTopRight.y - nodeSpaceBottomLeft.y;
    return CGRectMake(nodeSpaceBottomLeft.x, nodeSpaceBottomLeft.y, width, height);
}

/*!
 Return a CGRect computed as the union of this node's -boundingBox and those of
 this node's descendant nodes.
 */
-(CGRect) fullBoundingBox
{
    NSMutableArray *stack = [[NSMutableArray new] autorelease];
    float leftmost = [self boundingBox].origin.x;
    float rightmost = leftmost + [self boundingBox].size.width;
    float lowest = [self boundingBox].origin.y;
    float highest = lowest + [self boundingBox].size.height;
    for (CCNode *child in self.children) { [stack addObject:child]; }
    while ([stack count] > 0)
    {
        CCNode *node = [[stack lastObject] retain];
        [stack removeLastObject];
        CGRect bb = [self boundingBoxConvertedToNodeSpace:node];
        float nodeleftmost = bb.origin.x;
        float noderightmost = bb.origin.x + bb.size.width;
        float nodelowest = bb.origin.y;
        float nodehighest = bb.origin.y + bb.size.height;
        leftmost = fmin(leftmost,nodeleftmost);
        rightmost = fmax(rightmost,noderightmost);
        lowest = fmin(lowest,nodelowest);
        highest = fmax(highest,nodehighest);
        for (CCNode *child in node.children)
        {
            [stack addObject:child];
        }
        [node release];
    }
    float width = rightmost - leftmost;
    float height = highest - lowest;
    return CGRectMake(leftmost,lowest,width,height);
}