XSGIvcSetOutputGain(3)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
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XSGIvcSetOutputGain(3)XSGIvcSetOutputGain(3)
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
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