UIImageView Rotation Issue

Question

Right now I'm blending two images and one of the UIImages has the rotation gesture. but when I save the images the one with the rotation gesture doesn't save correctly it just stays the same and not rotated to the way the user placed it.

Here is my code.

- (void)handleRotate:(UIRotationGestureRecognizer *)recognizer {



    recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);
    recognizer.rotation = 0;


}

- (UIImage *) blendImages {
    UIImage *photoImage = self.photoView.image ;
    UIImage *toeImage = self.stacheView.image;


    CGSize photoSize = CGSizeMake(photoImage.size.width, photoImage.size.height);


    UIGraphicsBeginImageContext( photoSize );


    [photoImage drawInRect:CGRectMake(0,0,photoSize.width,photoSize.height)];

    CGPoint origin = self.stacheView.frame.origin;
    CGSize size = self.stacheView.frame.size;

    CGFloat xScale = photoImage.size.width / self.view.bounds.size.width;
    CGFloat yScale = photoImage.size.height / (self.view.bounds.size.height-44);


    [toeImage drawInRect:CGRectMake((origin.x * xScale), (origin.y * yScale),
                                       size.width * xScale, size.height * yScale)
                  blendMode:kCGBlendModeNormal alpha:1.0];


    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return newImage;
}

Answer 1 · 2014-01-04T01:15:51Z

January 4, 2014 1:15am

That's because your affine transform was applied to the view, which only serves as a container of the image you drew to your context. When you save it out, the image is read from your UIImageView (a container) without the transformation since the transform was applied to the view and not the image.

To save the rotation as well, you need to draw with the rotation. Check out the CGContextRotateCTM function.

https://developer.apple.com/library/ios/documentation/graphicsimaging/Reference/CGContext/Reference/reference.html#//apple_ref/c/func/CGContextRotateCTM

Answer 2 · 2014-01-10T21:33:22Z

January 10, 2014 9:33pm

Am I implementing the CGContextRotateCTM function in the rotation gesture or my image blending code? because I've been trying to put it in my blending code and it keeps rotating my photoView and distorting it.

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Alex Puray

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UIImageView Rotation Issue

2 Answers

John W

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Alex Puray

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