Crop UIView Snapshot












0















I'm implementing a custom UINavigationViewController transition, and as part of the animation I want to snapshot and transform the destination UIViewController. However, I want to slice the snapshot and transform the parts independently.



There is a comment in UIView.h that seems to indicate that this is possible and even recommended:




Creating snapshots from existing snapshots (as a method to duplicate, crop or create a resizable variant) is supported. In cases where many snapshots are needed, creating a snapshot from a common superview and making subsequent snapshots from it can be more performant.




However, I cannot figure out how to actually do the cropping or create multiple snapshots from the common superview snapshot.



Is this possible?




Note: I did investigate using UIView.drawHierarchy(in:afterScreenUpdates:) to create an image that I can later crop, however this fails during a UINavigationController transition with the following error:




[Snapshotting] View (0x140853600, MTKView) drawing with afterScreenUpdates:YES inside CoreAnimation commit is not supported.







ios uiview







share|improve this question





























    0















    I'm implementing a custom UINavigationViewController transition, and as part of the animation I want to snapshot and transform the destination UIViewController. However, I want to slice the snapshot and transform the parts independently.



    There is a comment in UIView.h that seems to indicate that this is possible and even recommended:




    Creating snapshots from existing snapshots (as a method to duplicate, crop or create a resizable variant) is supported. In cases where many snapshots are needed, creating a snapshot from a common superview and making subsequent snapshots from it can be more performant.




    However, I cannot figure out how to actually do the cropping or create multiple snapshots from the common superview snapshot.



    Is this possible?




    Note: I did investigate using UIView.drawHierarchy(in:afterScreenUpdates:) to create an image that I can later crop, however this fails during a UINavigationController transition with the following error:




    [Snapshotting] View (0x140853600, MTKView) drawing with afterScreenUpdates:YES inside CoreAnimation commit is not supported.







    ios uiview







    share|improve this question



























      0












      0








      0








      I'm implementing a custom UINavigationViewController transition, and as part of the animation I want to snapshot and transform the destination UIViewController. However, I want to slice the snapshot and transform the parts independently.



      There is a comment in UIView.h that seems to indicate that this is possible and even recommended:




      Creating snapshots from existing snapshots (as a method to duplicate, crop or create a resizable variant) is supported. In cases where many snapshots are needed, creating a snapshot from a common superview and making subsequent snapshots from it can be more performant.




      However, I cannot figure out how to actually do the cropping or create multiple snapshots from the common superview snapshot.



      Is this possible?




      Note: I did investigate using UIView.drawHierarchy(in:afterScreenUpdates:) to create an image that I can later crop, however this fails during a UINavigationController transition with the following error:




      [Snapshotting] View (0x140853600, MTKView) drawing with afterScreenUpdates:YES inside CoreAnimation commit is not supported.







      ios uiview







      share|improve this question
















      I'm implementing a custom UINavigationViewController transition, and as part of the animation I want to snapshot and transform the destination UIViewController. However, I want to slice the snapshot and transform the parts independently.



      There is a comment in UIView.h that seems to indicate that this is possible and even recommended:




      Creating snapshots from existing snapshots (as a method to duplicate, crop or create a resizable variant) is supported. In cases where many snapshots are needed, creating a snapshot from a common superview and making subsequent snapshots from it can be more performant.




      However, I cannot figure out how to actually do the cropping or create multiple snapshots from the common superview snapshot.



      Is this possible?




      Note: I did investigate using UIView.drawHierarchy(in:afterScreenUpdates:) to create an image that I can later crop, however this fails during a UINavigationController transition with the following error:




      [Snapshotting] View (0x140853600, MTKView) drawing with afterScreenUpdates:YES inside CoreAnimation commit is not supported.







      ios uiview




      ios uiview






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 13 '18 at 20:45







      Jayson

















      asked Nov 13 '18 at 20:39









      JaysonJayson

      757620




      757620
























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          Thanks to KMT over at the Apple forums, I found the solution:



          UIView.resizableSnapshotView(from:afterScreenUpdates:withCapInsets:)



          Passing in the desired cropping rect and UIEdgeInsets.zero for the cap insets correctly creates a cropped snapshot.






          share|improve this answer























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            1 Answer
            1






            active

            oldest

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            active

            oldest

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            active

            oldest

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            0














            Thanks to KMT over at the Apple forums, I found the solution:



            UIView.resizableSnapshotView(from:afterScreenUpdates:withCapInsets:)



            Passing in the desired cropping rect and UIEdgeInsets.zero for the cap insets correctly creates a cropped snapshot.






            share|improve this answer




























              0














              Thanks to KMT over at the Apple forums, I found the solution:



              UIView.resizableSnapshotView(from:afterScreenUpdates:withCapInsets:)



              Passing in the desired cropping rect and UIEdgeInsets.zero for the cap insets correctly creates a cropped snapshot.






              share|improve this answer


























                0












                0








                0







                Thanks to KMT over at the Apple forums, I found the solution:



                UIView.resizableSnapshotView(from:afterScreenUpdates:withCapInsets:)



                Passing in the desired cropping rect and UIEdgeInsets.zero for the cap insets correctly creates a cropped snapshot.






                share|improve this answer













                Thanks to KMT over at the Apple forums, I found the solution:



                UIView.resizableSnapshotView(from:afterScreenUpdates:withCapInsets:)



                Passing in the desired cropping rect and UIEdgeInsets.zero for the cap insets correctly creates a cropped snapshot.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 14 '18 at 19:07









                JaysonJayson

                757620




                757620






























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