Home/ Questions/Q 8591495
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-11T23:32:29+00:00

I’m trying to get the cropped version of an image that’s pulled using ALAsset.

  • 0

I’m trying to get the cropped version of an image that’s pulled using ALAsset. Specifically, I’m selecting items from the user’s Photo Library and then uploading them. The issue is that in the library thumbnail view, iOS is showing us the cropped version. When you select that thumbnail and pull that image’s asset using ALAsset, I get the full resolution version.
I did some research and couldn’t find anything that helps in getting a second coordinate system of where the cropping happens.

To test it, you need iOS5 to edit the image in your library. Select an image in your image library, select “Edit”, and crop the image. When you get the ALAsset you’ll get the full image, and if you sync using iPhoto, iPhoto also pulls the full image. Also, you can re-edit the image and undo your crop.

This is how I’m getting the image:

UIImage *tmpImage = [UIImage imageWithCGImage:[[asset defaultRepresentation] fullResolutionImage]];

That gives me the full resolution image, obviously. There’s a fullScreenImage flag which scales the full resolution image to the size of the screen. That’s not what I want.

The ALAssetRepresenation class has a scale field, but that’s a float value, which is also what I don’t want.

If anyone can tell me where this cropped coordinate system can be found, I’d appreciate it.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    When a photo has been cropped with the iOS Photos App, the cropping coordinates can be found in the ALAssetRepresentation’s metadata dictionary. fullResolutionImage will give you the uncropped photo, you have to perform the cropping yourself.

    The AdjustmentXMP metadata contains not only the cropping coordinates but also indicates if auto-enhance or remove-red-eyes has been applied.

    As of iOS 6.0 CIFilter provides filterArrayFromSerializedXMP:inputImageExtent:error: Probably you can use the ALAssetRepresentation’s AdjustmentXMP metadata here and apply the CIFilter onto the ALAssetRepresentation’s fullResolutionImage to recreate the modified image.

    Be aware that the iOS Photos App handles JPG and RAW images differently. For JPG images a new ALAsset with the XMP metadata is stored in the Camera Roll. For RAW images an ALAssetRepresentation is added to the original ALAsset. I’m not sure if this additional ALAssetRepresentation is the modified image and if it has the AdjustmentXMP metadata. In addition to JPG and RAW images you should also test the behaviour for RAW+JPG images.

    • 0