1991-2006
Silicon Graphics, Inc.
glGetColorTableParameter
3G

# glGetColorTableParameter

get color lookup table parameters

## C Specification

                    void glGetColorTableParameterfv
                    GLenum target
                    GLenum pname
                    GLfloat * params

                    void glGetColorTableParameteriv
                    GLenum target
                    GLenum pname
                    GLint * params

## Parameters

`target`

  The target color table. Must be `GL_COLOR_TABLE`, `GL_POST_CONVOLUTION_COLOR_TABLE`, `GL_POST_COLOR_MATRIX_COLOR_TABLE`, `GL_PROXY_COLOR_TABLE`, `GL_PROXY_POST_CONVOLUTION_COLOR_TABLE`, or `GL_PROXY_POST_COLOR_MATRIX_COLOR_TABLE`.

`pname`

  The symbolic name of a color lookup table parameter. Must be one of `GL_COLOR_TABLE_BIAS`, `GL_COLOR_TABLE_SCALE`, `GL_COLOR_TABLE_FORMAT`, `GL_COLOR_TABLE_WIDTH`, `GL_COLOR_TABLE_RED_SIZE`, `GL_COLOR_TABLE_GREEN_SIZE`, `GL_COLOR_TABLE_BLUE_SIZE`, `GL_COLOR_TABLE_ALPHA_SIZE`, `GL_COLOR_TABLE_LUMINANCE_SIZE`, or `GL_COLOR_TABLE_INTENSITY_SIZE`.

`params`

  A pointer to an array where the values of the parameter will be stored.

## Description

Returns parameters specific to color table `target`.

When `pname` is set to `GL_COLOR_TABLE_SCALE` or `GL_COLOR_TABLE_BIAS`, `glGetColorTableParameter` returns the color table scale or bias parameters for the table specified by `target`. For these queries, `target` must be set to `GL_COLOR_TABLE`, `GL_POST_CONVOLUTION_COLOR_TABLE`, or `GL_POST_COLOR_MATRIX_COLOR_TABLE` and `params` points to an array of four elements, which receive the scale or bias factors for red, green, blue, and alpha, in that order.

`glGetColorTableParameter` can also be used to retrieve the format and size parameters for a color table. For these queries, set `target` to either the color table target or the proxy color table target. The format and size parameters are set by glColorTable.

The following table lists the format and size parameters that may be queried. For each symbolic constant listed below for `pname`, `params` must point to an array of the given length and receive the values indicated.

Parameter | N | Meaning
--- | --- | ---
`GL_COLOR_TABLE_FORMAT` | 1 | Internal format (e.g., `GL_RGBA`)
`GL_COLOR_TABLE_WIDTH` | 1 | Number of elements in table
`GL_COLOR_TABLE_RED_SIZE` | 1 | Size of red component, in bits
`GL_COLOR_TABLE_GREEN_SIZE` | 1 | Size of green component
`GL_COLOR_TABLE_BLUE_SIZE` | 1 | Size of blue component
`GL_COLOR_TABLE_ALPHA_SIZE` | 1 | Size of alpha component
`GL_COLOR_TABLE_LUMINANCE_SIZE` | 1 | Size of luminance component
`GL_COLOR_TABLE_INTENSITY_SIZE` | 1 | Size of intensity component

## Notes

`glGetColorTableParameter` 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` or `pname` is not an acceptable value.

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

## See Also

glColorTable, glTexParameter, glColorTableParameter

## 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/.