CAGradientLayer with CAShapeLayer mask not showing - ios

Question

I have the following code:
- (void)setupLayer {
self.faucetShape = [CAShapeLayer layer];
self.faucetShape.strokeColor = [[UIColor blackColor] CGColor];
self.faucetShape.lineWidth = 2;
self.faucetShape.fillColor = nil;
self.faucetShape.path = [self faucetPath].CGPath; // faucetPath returns a 4 point diamond shaped UIBezierPath*
self.faucet = [CAGradientLayer layer];
self.faucet.mask = self.faucetShape;
self.faucet.colors = #[(id)[UIColor redColor].CGColor, (id)[UIColor redColor].CGColor];
[self.layer addSublayer: self.faucet];
}
But it shows nothing. Not sure what I'm missing (other than my graphic).
(faucet and faucetPath are both properties)
UPDATE
OK, I guess a CAGradientLayer has to have a meaningful frame. I assume a CAShapeLayer's frame isn't as meaningful, since the path can go outside the frame. Adding the following line made it show up:
self.faucet.frame = CGRectMake(0, 0, 64, 64);
So NOW my question is, is there a way to avoid having to do that? I'd just like the frame of the layer to implicitly be that of the containing View/Layer.

Answer 1

You need to set the frame of the layers. The following code will draw a red circle:
- (void)setupLayer
{
CAShapeLayer *faucetShape = [CAShapeLayer layer];
faucetShape.frame = CGRectMake(0, 0, 100, 100);
faucetShape.strokeColor = [[UIColor blackColor] CGColor];
faucetShape.lineWidth = 2;
faucetShape.fillColor = nil;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddEllipseInRect(path, nil, CGRectMake(0, 0, 100, 100));
faucetShape.path = path;
CGPathRelease(path);
CAGradientLayer *faucet = [CAGradientLayer layer];
faucet.frame = CGRectMake(10, 10, 100, 100);
faucet.mask = faucetShape;
faucet.colors = #[(id)[UIColor redColor].CGColor, (id)[UIColor redColor].CGColor];
[self.view.layer addSublayer: faucet];
}