CATransform3D equivavelent to CGPointApplyAffineTransform and friends

Question

How can I write the CATransform3D equivalent to

CGPoint CGPointApplyAffineTransform(CGPoint point, CGAffineTransform t)
CGSize CGSizeApplyAffineTransform(CGSize size, CGAffineTransform t);
CGRect CGRectApplyAffineTransform(CGRect rect, CGAffineTransform t);

?

Answer 1

This works, but it would ofcourse be a lot better to know what happens inside -[CALayer convertPoint:toLayer:] !

CGPoint CGPointApplyCATransform3D(CGPoint point, CATransform3D transform, CGPoint anchorPoint, CATransform3D parentSublayerTransform)
{

    static pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;
    static CALayer *sublayer, *layer;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sublayer = [CALayer layer];
        layer = [CALayer layer];
        [layer addSublayer:sublayer];
    });

    if(pthread_mutex_lock(&mtx))
    {
        [NSException raise:NSInternalInconsistencyException format:@"pthread_mutex_lock failed"];
    }

    layer.sublayerTransform = parentSublayerTransform;
    sublayer.transform = transform;
    sublayer.anchorPoint = anchorPoint;
    CGPoint retval = [sublayer convertPoint:point toLayer:layer];

    if(pthread_mutex_unlock(&mtx) != 0)
    {
        [NSException raise:NSInternalInconsistencyException format:@"pthread_mutex_unlock failed"];
    } 

    return retval;
}

Simple unit tests https://gist.github.com/hfossli/5130975