Detect CCSprite touch in small distance between them - cocos2d-iphone

Question

I have some small sprites (width/height) in a CCLayer and i want to detect which of them is touched. I use the following code.
- (BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
CGPoint touchLocation = [self convertTouchToNodeSpace:touch];
CGRect rect = sprite.boundingBox;
// i am doing this because of the small size of the sprites,
// so it would be more easy to detect if a sprite is taped and then move it.
if (rect.size.width > rect.size.height) {
rect.size.width *= 2.5;
rect.size.height *= 5;
rect.origin.y -= rect.size.height / 2;
} else {
rect.size.width *= 5;
rect.size.height *= 2.5;
rect.origin.x -= rect.size.width / 2;
}
CCSprite *s = nil;
for (CCSprite *sprite in [self children]) {
if (CGRectContainsPoint(rect, touchPoint)) {
s = sprite;
break;
}
}
if (s != nil) {
// do something here
}
return YES;
}
All works fine except when two sprites is very close (not overlap) to each other. Then because of the small distance between them, the wrong sprite is detected.
Any idea how could i correct it?

Answer 1

If you are trying to enlarge the rects keeping their center where it originally is, you should use:
rect.origin.y -= (rectFinalHeight - rectOriginalHeight) / 2;
and
rect.origin.y -= (rectFinalWidth - rectOriginalWidth) / 2;
which would be:
if (rect.size.width > rect.size.height) {
rect.size.width *= 2.5;
rect.size.height *= 5;
rect.origin.y -= rect.size.height * 4 / 2;
} else {
rect.size.width *= 5;
rect.size.height *= 2.5;
rect.origin.x -= rect.size.width * 4 / 2;
}
IMO, you should adjust the rect origin along both axis in both cases (and not only in one case along the x axis and in the other along the y axis), otherwise your rect will not be centered. But you understand better what you are trying to do, here...