[Objective C] (UIImage*)rotate 이미지 회전 코드

Objective C 에서 이미지를 회전 시키는 코드 입니다.

-(UIImage*)rotate:(UIImageOrientation)orient
{
    CGRect             bnds = CGRectZero;
    UIImage*           copy = nil;
    CGContextRef       ctxt = nil;
    CGRect             rect = CGRectZero;
    CGAffineTransform  tran = CGAffineTransformIdentity;

    bnds.size = self.size;
    rect.size = self.size;

    switch (orient)
    {
        case UIImageOrientationUp:
        return self;

        case UIImageOrientationUpMirrored:
        tran = CGAffineTransformMakeTranslation(rect.size.width, 0.0);
        tran = CGAffineTransformScale(tran, -1.0, 1.0);
        break;

        case UIImageOrientationDown:
        tran = CGAffineTransformMakeTranslation(rect.size.width,
         rect.size.height);
        tran = CGAffineTransformRotate(tran, degreesToRadians(180.0));
        break;

        case UIImageOrientationDownMirrored:
        tran = CGAffineTransformMakeTranslation(0.0, rect.size.height);
        tran = CGAffineTransformScale(tran, 1.0, -1.0);
        break;

        case UIImageOrientationLeft:
        bnds.size = swapWidthAndHeight(bnds.size);
        tran = CGAffineTransformMakeTranslation(0.0, rect.size.width);
        tran = CGAffineTransformRotate(tran, degreesToRadians(-90.0));
        break;
        case UIImageOrientationLeftMirrored:
        bnds.size = swapWidthAndHeight(bnds.size);
        tran = CGAffineTransformMakeTranslation(rect.size.height,
         rect.size.width);
        tran = CGAffineTransformScale(tran, -1.0, 1.0);
        tran = CGAffineTransformRotate(tran, degreesToRadians(-90.0));
        break;

        case UIImageOrientationRight:
        bnds.size = swapWidthAndHeight(bnds.size);
        tran = CGAffineTransformMakeTranslation(rect.size.height, 0.0);
        tran = CGAffineTransformRotate(tran, degreesToRadians(90.0));
        break;

        case UIImageOrientationRightMirrored:
        bnds.size = swapWidthAndHeight(bnds.size);
        tran = CGAffineTransformMakeScale(-1.0, 1.0);
        tran = CGAffineTransformRotate(tran, degreesToRadians(90.0));
        break;

        default:
        // orientation value supplied is invalid
        assert(false);
        return nil;
    }

    UIGraphicsBeginImageContext(bnds.size);
    ctxt = UIGraphicsGetCurrentContext();

    switch (orient)
    {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
        CGContextScaleCTM(ctxt, -1.0, 1.0);
        CGContextTranslateCTM(ctxt, -rect.size.height, 0.0);
        break;

        default:
        CGContextScaleCTM(ctxt, 1.0, -1.0);
        CGContextTranslateCTM(ctxt, 0.0, -rect.size.height);
        break;
    }

    CGContextConcatCTM(ctxt, tran);
    CGContextDrawImage(ctxt, rect, self.CGImage);

    copy = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return copy;
}

여기저기 참고를 했는데 너무 오래되서 기억이 안나네요.