Rotated UIImage generator

Generator.m

- (void) run {
	UIImage *img = [UIImage imageNamed: @"SampleImage@2x"];

	for( int i = 0; i< 40; i++ ){
		CGFloat degree = i * 4.5f;
		NSString *dirName = @"/Users/john/Desktop";
		NSString *fileName = [NSString stringWithFormat: @"%@/IconAnim%[email protected]", dirName, i];

		NSData *data = [self rotate: img withDegree: degree];
		if( [data writeToFile: fileName atomically: YES] == YES ){
			NSLog(@"file %@ created.", fileName);
		}
		else{
			NSLog(@"file %@ failed to create !", fileName);
		}
	}
}

- (NSData *) rotate: (UIImage *) image withDegree: (CGFloat) degree {
	UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);

	CGRect frame = CGRectMake(0, 0, image.size.width, image.size.height);
	CGContextRef context = UIGraphicsGetCurrentContext();

	CGContextSaveGState(context);

	// move to center pos
	CGContextTranslateCTM(context, image.size.width / 2, image.size.height / 2);
	CGContextScaleCTM(context, 1, -1);
	CGContextRotateCTM(context, - M_PI_2 / 90 * degree);

	// move back
	CGContextTranslateCTM(context, - image.size.width / 2, - image.size.height / 2);

	CGContextDrawImage(context, frame, image.CGImage);

	CGContextRestoreGState(context);

	UIImage *screenImage = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();

	return UIImagePNGRepresentation( screenImage );
}