iOS -> 将 2 UIImageView 保存到 cameraRoll

Question

i have two layers of UIImageView, upper one is partly transparent, second in is 'background'. I want to save them both like user see them from front into cameraRoll for user's use. The problem is writing it in way:

if(gridUpperLayer == transparent) {drawGridLowerLayer} 
else {drawGridUpperLayer} 

will be very slow (and i dont know how to implement it). Anybody has idea how to do it in faster way..? Best would be with example but i would be grateful for anything ^^ Cheers and thank you in advance!

Answer 1

You can do this by rendering the CALayer into an image for the UIView that contains both of the images. The following code would look like:

UIGraphicsBeginImageContext(containerView.frame.size);
[containerView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *anImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

//save anImage to disk