Encapsulate drawRect gradients in CAGradientLayer - ios

Question

There are dozens of excellent examples on here and elsewhere of how to use gradients by
-(void)drawRect:(CGRect)rect
However, I'm new to Quartz and it's likely I'm missing something. When I found this, it seems more intelligent to create a CAGradientLayer and then add it to my view with something like:
-(void)viewWillAppear
{
CAGradientLayer *bgLayer = [BackgroundLayer blueGradient];
bgLayer.frame = self.view.bounds;
[self.view.layer insertSublayer:bgLayer atIndex:0];
}
Where the blueGradient is a separate class method (within BackgroundLayer.m) which creates the gradient, as follows:
+ (CAGradientLayer*) blueGradient {
UIColor *colorOne = [UIColor colorWithRed:(120/255.0) green:(135/255.0) blue:(150/255.0) alpha:1.0];
UIColor *colorTwo = [UIColor colorWithRed:(57/255.0) green:(79/255.0) blue:(96/255.0) alpha:1.0];
NSArray *colors = [NSArray arrayWithObjects:(id)colorOne.CGColor, colorTwo.CGColor, nil];
NSNumber *stopOne = [NSNumber numberWithFloat:0.0];
NSNumber *stopTwo = [NSNumber numberWithFloat:1.0];
NSArray *locations = [NSArray arrayWithObjects:stopOne, stopTwo, nil];
CAGradientLayer *headerLayer = [CAGradientLayer layer];
headerLayer.colors = colors;
headerLayer.locations = locations;
return headerLayer;
}
So here's my question. What if instead of this simple linear gradient, I want to create a radial one? How can I extend blueGradient so that it can handle two dimensional gradients? Or what if I want to add gradients on top of gradients? the drawRect function seems so limiting.
Or maybe that's just the wrong approach... then what's the wiring that I'm missing? How do I add gradients to my view(s) using drawRect? I want to be sure I'm doing it in a modular way so I can add gradient overlays, etc, as additional layers as necessary.

Answer 1

As of iOS 7, CAGradientLayer can only draw a linear gradient. It cannot draw a radial gradient.
You can either use the drawRect: approach, or you can draw your gradient into an image and display the image in a view or layer. You can draw it into a UIImage and display it in a UIImageView, or you can draw it into a CGImage and set it as the contents of a CALayer.