hello,i want to caculate the time it takes get the image from io util render to UIImageView ,my code like this:
NSDate *ad = [NSDate date];
NSData *data = [NSData dataWithContentsOfFile:downloadURL.relativePath];
CFDataRef dataRef = (__bridge CFDataRef)data;
CGImageSourceRef source =CGImageSourceCreateWithData(dataRef, nil);
CGImageRef cgImage =CGImageSourceCreateImageAtIndex(source, 0, nil);
CFDataRef rawData =CGDataProviderCopyData(CGImageGetDataProvider(cgImage));
NSDate *bd = [NSDate date];
NSLog(@"time dis :%f",[bd timeIntervalSinceDate:ad]);
but i find that large image always take longer than small image,i can't understand ,can you give me some advice