XSGIvcSetOutputGain(3)

     NAME
          XSGIvcSetOutputGain, XSGIvcQueryOutputGain - Video Gain
          Operations

     SYNOPSIS
          #include <X11/extensions/XSGIvc.h>

          void XSGIvcSetOutputGain(Display *display,
              int screen,
              int channel,
              int componentID,
              float gain)

          Status XSGIvcQueryOutputGain(Display *display,
              int screen,
              int channel,
              int componentID,
              float *gainReturn)

     PARAMETERS
          display     Specifies the connection to the X server.

          screen      Specifies the screen of the X server.

          channel     Specifies the channel number.

          componentID Specifies the color component which is the
                      subject of the call.  This can be one of
                      XSGIVC_COMPONENT_RED, XSGIVC_COMPONENT_GREEN,
                      XSGIVC_COMPONENT_BLUE, XSGIVC_COMPONENT_ALPHA,
                      or XSGIVC_COMPONENT_ALL.

          gain        The value to which the gain should be set.

          gainReturn  Pass a pointer to the location which is to
                      receive the value to which the color component
                      gain is set.



     DESCRIPTION
          These functions allow alteration and query of video gain
          values and is intended for use by color correction and gamma
          management tools.  Arbitrary use of this control may
          conflict with these tools.

          The gain value is specified in arbitrary units, where the
          following are points of interest:

          0.0    Lowest useful value

          1.0    Nominal value
          10.0   Highest possible value


          Precision depends upon server implementation and although is
          monotonically increasing is not guaranteed to be uniform
          across the full range.  You should use XSGIvcQueryOutputGain
          to retrieve the current setting from the server after a set
          operation to determine the value to which the server is set.
          XSGIvcSetOutputGain() sets the video output gain of the
          components of a channel.

          XSGIvcQueryOutputGain() returns the current settings for
          each of the components of a channel.


        Component Specification
          A server may support independent adjustment of each
          component, or may support only a global change; refer to
          hardware documentation for information on server support or
          reference the XSGIVC_CIFPerComponentGain mask bit in the
          field channelFlag as returned in the XSGIVCQueryChannelInfo
          function.  This mask bit is True when the server supports
          independent gain adjustment of each component on the
          channel.  Applications written for use on more than one type
          of hardware should query all color component values after
          setting one.

          For servers that permit independent adjustment, any
          component of XSGIVC_COMPONENT_RED, XSGIVC_COMPONENT_GREEN,
          XSGIVC_COMPONENT_BLUE, or XSGIVC_COMPONENT_ALPHA may be
          specified.  For servers that support only simultaneous,
          ganged change of the gain for all components, use
          XSGIVC_COMPONENT_ALL.


     EVENTS
          When this control is altered, the server generates a
          OutputGainNotify event.


     RETURNED VALUE
          XSGIvcQueryOutputGain returns TRUE if successful, FALSE upon
          failure.

          Parameter errors are reported via BadValue or BadMatch.


     SEE ALSO
          XSGIvc