Draw rotated and scaled UILabel text inside UIImage - ios

Question

I have one UIScrollView with a UIImageView inside from where I obtain a cropped UIImage (considering scale, offset, bounds,...). On the other hand, I have a UILabel which I can rotate, pinch and pan anywhere over the UIScrollView. The problem comes when I try to generate the final image with the label text inside (with it's original/equivalent position, rotation,...) on the cropped UIImage (bigger than screen size).
I've tried everything. This is my last attempt trying to position the text, but it's always misplaced.
// Compute rect to draw the text inside
CGSize imageSize = inImage.size;
NSDictionary *attr = #{NSForegroundColorAttributeName: fontColor, NSFontAttributeName: textFont};
CGSize textSize = [text sizeWithAttributes:attr];
CGRect textRect = CGRectMake(labelCenterPoint.x, labelCenterPoint.y, textSize.width, textSize.height);
// Create the image
UIGraphicsBeginImageContext(imageSize);
[inImage drawInRect:CGRectMake(0, 0, imageSize.width, imageSize.height)];
// Rotate text from center
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM( context, 0.5f * textSize.width, 0.5f * textSize.height ) ;
CGContextRotateCTM(context, rotation);
[text drawInRect:CGRectIntegral(textRect) withAttributes:attr];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
I think the problem is the textRect origin. Do I have to make the UILabel a subView of the UIScrollView too and make the textRect origin relative to the UIScrollView parameters? or am I missing something?. Is there a better way?.
Thanks in advance!.
Edit:
I have finally found an acceptable solution (although is not too much precise). I think the problem was about the two existing coordinate systems, so I tried a different approach:
// Calculate the relative position of the UILabel with respect
// to the ScrollView that contains the image
float xPosition = label.frame.origin.x - scrollView.frame.origin.x;
float yPosition = label.frame.origin.y - scrollView.frame.origin.y;
// Calculate the proportion to apply to the position
// (the image is bigger than screen)
float xProportion = image.frame.size.width / scrollView.frame.size.width;
float yProportion = image.frame.size.height / scrollView.frame.size.height;
UIImageView *testView = [[UIImageView alloc] initWithImage:image];
UILabel *tempLabel = [[UILabel alloc] initWithFrame:
CGRectMake((xPosition*xProportion),
(yPosition*yProportion),
label.frame.size.width*xProportion,
label.frame.size.height*yProportion)];
tempLabel.text = label.text;
tempLabel.font = [UIFont fontWithName:label.font.fontName
size:label.font.pointSize*3];
tempLabel.textColor = label.textColor;
tempLabel.textAlignment = NSTextAlignmentCenter;
tempLabel.transform = CGAffineTransformMakeRotation(rotation);
tempLabel.adjustsFontSizeToFitWidth = YES;
tempLabel.minimumScaleFactor = 0.05;
[testView addSubview:tempLabel];
UIGraphicsBeginImageContext(testView.image.size);
[testView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *imageWithText = UIGraphicsGetImageFromCurrentImageContext();
I hope this may help someone. All suggestions are welcome of course.