public static extern int HeifContextGetListOfTopLevelImageIDs(HeifContextPointer ctx, UIntPtr idArray, int count);
public static extern IntPtr HeifContextGetImageHandle(HeifContextPointer ctx, HeifItemId id, ref HeifImageHandlePointer imgHdl);
public static extern int HeifContextGetNumberOfTopLevelImages(HeifContextPointer ctx);
public static extern IntPtr HeifContextGetPrimaryImageHandle(HeifContextPointer ctx, ref HeifImageHandlePointer imgHdl);
public static extern IntPtr HeifContextGetPrimaryImageID(HeifContextPointer ctx, ref HeifItemId id);
public static extern IntPtr HeifContextReadFromMemoryWithoutCopy(HeifContextPointer ctx, [In] IntPtr mem, UIntPtr size, [In] UIntPtr unused);
public static extern void HeifContextFree(HeifContextPointer ctx);