How to check if a uiimage is blank? (empty, transparent)

Question

which is the best way to check whether a UIImage is blank?
I have this painting editor which returns a UIImage; I don\'t want to save this imag

Answer 1

One idea would be to call UIImagePNGRepresentation to get an NSData object then compare it with a pre-defined 'empty' version - ie: call:

- (BOOL)isEqualToData:(NSData *)otherData

to test?

Not tried this on large data; might want to check performance, if your image data is quite large, otherwise if it's small it is probably just like calling memcmp() in C.