Checking if UIGraphicsBeginImageContextWithOptions is supported

Question

I\'m working on an iOS app. It currently only works on iOS 4 since I use the following method on several occasions: \"UIGraphicsBeginImageContextWithOptions\". This method i

Answer 1

I know this is an old question, but with new Xcode and iOS versions (upper than 9) any of this methods work for me.

I always check the system version in this way:

NSString *sysver = [[UIDevice currentDevice] systemVersion];
NSArray *versionNums = [sysver componentsSeparatedByString:@"."];
int majorVersion = [versionNums[0] intValue];
if (majorVersion > 3){
    UIGraphicsBeginImageContextWithOptions(...);
}
else{
    UIGraphicsBeginImageContext(...);
}

I hope this could help anyone.

Answer 2

I have the same problem. You could try testing the system version. This seems to work for me on the devices I tested.

char majorVersion = [[[UIDevice currentDevice] systemVersion] characterAtIndex: 0];
if (majorVersion == '2' || majorVersion == '3')
     UIGraphicsBeginImageContext(...);
else
     UIGraphicsBeginImageContextWithOptions(...);

Answer 3

UIGraphicsBeginImageContextWithOptions is a C function, so you can't use Objective-C methods like -respondsToSelector: to test its existence.

You could, however, weak link the UIKit framework, and then check if UIGraphicsBeginImageContextWithOptions is NULL:

if (UIGraphicsBeginImageContextWithOptions != NULL) {
   UIGraphicsBeginImageContextWithOptions(...);
} else {
   UIGraphicsBeginImageContext(...);
}