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How do I create/render a UIImage from a 3D transformed UIImageView?

Asked 2009-12-22T20:39:34.363
15

After applying a 3d transform to an UIImageView.layer, I need to save the resulting "view" as a new UIImage... Seemed like a simple task at first :-) but no luck so far, and searching hasn't turned up any clues :-( so I'm hoping someone will be kind enough to point me in the right direction.

A very simple iPhone project is available here.

Thanks.

- (void)transformImage {
    float degrees = 12.0;
    float zDistance = 250;
    CATransform3D transform3D = CATransform3DIdentity;
    transform3D.m34 = 1.0 / zDistance; // the m34 cell of the matrix controls perspective, and zDistance affects the "sharpness" of the transform
    transform3D = CATransform3DRotate(transform3D, DEGREES_TO_RADIANS(degrees), 1, 0, 0); // perspective transform on y-axis
    imageView.layer.transform = transform3D;
}

/* FAIL : capturing layer contents doesn't get the transformed image -- just the original

CGImageRef newImageRef = (CGImageRef)imageView.layer.contents;

UIImage *image = [UIImage imageWithCGImage:newImageRef];

*/


/* FAIL : docs for renderInContext states that it does not render 3D transforms

UIGraphicsBeginImageContext(imageView.image.size);

[imageView.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

*/
//
// header
//
#import <QuartzCore/QuartzCore.h>
#define DEGREES_TO_RADIANS(x) x * M_PI / 180
UIImageView *imageView;
@property (nonatomic, retain) IBOutlet UIImageView *imageView;

//
// code
//
@synthesize imageView;

- (void)transformImage {
    float degrees = 12.0;
    float zDistance = 250;
    CATransform3D transform3D = CATransform3DIdentity;
    transform3D.m34 = 1.0 / zDistance; // the m34 cell of the matrix controls perspective, and zDistance affects the "sharpness" of the transform
    transform3D = CATransform3DRotate(transform3D, DEG
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1 Answer

1

Have you had a look at this? UIImage from UIView

answered 2010-01-05T17:31:59.387

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