It's a bit tricky th create a CATextLayer in iOS:

Firstly, remember to explicitly set the frame size of the layer:

CATextLayer *textLayer = [CATextLayer layer];
// set the string
textLayer.string = @"Hello world";
textLayer.foregroundColor = [UIColor blackColor].CGColor;
textLayer.frame = CGRectMake(0, 0, 100, 20);

Then you may wonder how to set the CFTypeRef type for font. Actually simply cast the font name will do:

textLayer.font = (__bridge CFTypeRef)@"AmericanTypewriter-CondensedLight";
textLayer.fontSize = 18;
textLayer.alignmentMode = kCAAlignmentCenter;

Lastly, remember to set the contentsScale to match the scale of the screen of the device, otherwise the output will be very ugly on retina display device:

textLayer.contentsScale = [[UIScreen mainScreen] scale];