Copyright © 2015 Giulio camuffo
    Copyright © 2018 Simon Ser
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    This protocol allows a privileged client to set the gamma tables for
    outputs.
    Warning! The protocol described in this file is experimental and
    backward incompatible changes may be made. Backward compatible changes
    may be added together with the corresponding interface version bump.
    Backward incompatible changes are done by bumping the version number in
    the protocol and interface names and resetting the interface version.
    Once the protocol is to be declared stable, the 'z' prefix and the
    version number in the protocol and interface names are removed and the
    interface version number is reset.
  
  
    
      This interface is a manager that allows creating per-output gamma
      controls.
    
    
      
        Create a gamma control that can be used to adjust gamma tables for the
        provided output.
      
      
      
    
    
      
        All objects created by the manager will still remain valid, until their
        appropriate destroy request has been called.
      
    
  
  
    
      This interface allows a client to adjust gamma tables for a particular
      output.
      The client will receive the gamma size, and will then be able to set gamma
      tables. At any time the compositor can send a failed event indicating that
      this object is no longer valid.
      There must always be at most one gamma control object per output, which
      has exclusive access to this particular output. When the gamma control
      object is destroyed, the gamma table is restored to its original value.
    
    
      
        Advertise the size of each gamma ramp.
        This event is sent immediately when the gamma control object is created.
      
      
    
    
      
    
    
      
        Set the gamma table. The file descriptor can be memory-mapped to provide
        the raw gamma table, which contains successive gamma ramps for the red,
        green and blue channels. Each gamma ramp is an array of 16-byte unsigned
        integers which has the same length as the gamma size.
        The file descriptor data must have the same length as three times the
        gamma size.
      
      
    
    
      
        This event indicates that the gamma control is no longer valid. This
        can happen for a number of reasons, including:
        - The output doesn't support gamma tables
        - Setting the gamma tables failed
        - Another client already has exclusive gamma control for this output
        - The compositor has transferred gamma control to another client
        Upon receiving this event, the client should destroy this object.
      
    
    
      
        Destroys the gamma control object. If the object is still valid, this
        restores the original gamma tables.