UIImageView: get transformed UIImage

Question

I\'m rotating UIImageView using this:

[UIView beginAnimations:nil context:nil];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationCurve:UI         


        

Answer 1

OK, I'm answering my own question again, hopefully it will be useful for somebody in future... Coming back to CGImageRotatedByAngle as I previously said it gives almost required effect but coordinate system translation sequence must be slighly altered. And here is the way I got the desired result:

- (CGImageRef)CGImageRotatedByAngle:(CGImageRef)imgRef angle:(CGFloat)angle {

    CGFloat angleInRadians = angle * (M_PI / 180);
    CGFloat width = CGImageGetWidth(imgRef);
    CGFloat height = CGImageGetHeight(imgRef);

    CGRect imgRect = CGRectMake(0, 0, width, height);
    CGAffineTransform transform = CGAffineTransformMakeRotation(angleInRadians);
    CGRect rotatedRect = CGRectApplyAffineTransform(imgRect, transform);
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef bmContext = CGBitmapContextCreate(NULL,
                                                   rotatedRect.size.width,
                                                   rotatedRect.size.height,
                                                   8,
                                                   0,
                                                   colorSpace,
                                                   kCGImageAlphaPremultipliedFirst);
    CGContextSetAllowsAntialiasing(bmContext, YES);
    CGContextSetShouldAntialias(bmContext, YES);
    CGContextSetInterpolationQuality(bmContext, kCGInterpolationHigh);
    CGColorSpaceRelease(colorSpace);
    CGContextTranslateCTM( bmContext, 0.5f * rotatedRect.size.width, 0.5f * rotatedRect.size.height ) ;
    CGContextRotateCTM(bmContext, angleInRadians);
    CGContextDrawImage(bmContext, CGRectMake(-imgRect.size.width* 0.5f, -imgRect.size.height * 0.5f,
                                             imgRect.size.width,
                                             imgRect.size.height),
                       imgRef);
    CGImageRef rotatedImage = CGBitmapContextCreateImage(bmContext);
    CFRelease(bmContext);
    [(id)rotatedImage autorelease];

    return rotatedImage;
}