UIImage collision effect...??? Iphone

I 开发者_开发知识库need a way to create a collide effect, without the actual collision between the two images. Let me explain in more detail... If I have one fixed image and one image that is moving both images are on the same x coordinate at different positions. Basically I want the images appear to be colliding.I would want to run a check on the moving image like this...

If (front of moving image is clear)

{[move forward];}

else {[stop];}

How would I implement this in code??? So that right before the moving image collides into the fixed image it stops, so that they appear to have collided.This check would also be running on a 1/60 NSTimer.

Any advice is welcome. Thank you.

Assuming the object is moving from the left

#define PIXELS_PER_FRAME 1

-(CGFloat) getCurrentX:(UIImage*)image
{
    return image.frame.origin.x + image.frame.size.width;
}

-(void) moveImageToStableImage
{
    CGFloat xTarget = stableImage.frame.origin.x;
    if([self getCurrentX:movingImage] < xTarget)
    {
        movingImage.frame.origin.x += PIXELS_PER_FRAME;
        [self performSelector:@selector(moveImageToStableImage) withObject:nil afterDelay:1.0/60];
    }
}

But truth be told in this situation you would probably just be better off using an animation