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Name

glGetHistogramParameter — get histogram parameters

C Specification

void glGetHistogramParameterfv(GLenum  target,
 GLenum  pname,
 GLfloat *  params);
void glGetHistogramParameteriv(GLenum  target,
 GLenum  pname,
 GLint *  params);

Parameters

target

Must be one of GL_HISTOGRAM or GL_PROXY_HISTOGRAM.

pname

The name of the parameter to be retrieved. Must be one of GL_HISTOGRAM_WIDTH, GL_HISTOGRAM_FORMAT, GL_HISTOGRAM_RED_SIZE, GL_HISTOGRAM_GREEN_SIZE, GL_HISTOGRAM_BLUE_SIZE, GL_HISTOGRAM_ALPHA_SIZE, GL_HISTOGRAM_LUMINANCE_SIZE, or GL_HISTOGRAM_SINK.

params

Pointer to storage for the returned values.

Description

glGetHistogramParameter is used to query parameter values for the current histogram or for a proxy. The histogram state information may be queried by calling glGetHistogramParameter with a target of GL_HISTOGRAM (to obtain information for the current histogram table) or GL_PROXY_HISTOGRAM (to obtain information from the most recent proxy request) and one of the following values for the pname argument:

Parameter Description
GL_HISTOGRAM_WIDTH Histogram table width
GL_HISTOGRAM_FORMAT Internal format
GL_HISTOGRAM_RED_SIZE Red component counter size, in bits
GL_HISTOGRAM_GREEN_SIZE Green component counter size, in bits
GL_HISTOGRAM_BLUE_SIZE Blue component counter size, in bits
GL_HISTOGRAM_ALPHA_SIZE Alpha component counter size, in bits
GL_HISTOGRAM_LUMINANCE_SIZE Luminance component counter size, in bits
GL_HISTOGRAM_SINK Value of the sink parameter

Notes

glGetHistogramParameter is present only if ARB_imaging is returned when glGetString is called with an argument of GL_EXTENSIONS.

Errors

GL_INVALID_ENUM is generated if target is not one of the allowable values.

GL_INVALID_ENUM is generated if pname is not one of the allowable values.

GL_INVALID_OPERATION is generated if glGetHistogramParameter is executed between the execution of glBegin and the corresponding execution of glEnd.

See Also

glGetHistogram, glHistogram

Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.