GLUSCALEIMAGE(3G)

NAME
gluScaleImage - scale an image to an arbitrary size

C SPECIFICATION

GLint gluScaleImage(GLenum format, GLsizei wIn, GLsizei hIn, GLenum typeIn, const void * dataIn, GLsizei wOut, GLsizei hOut, GLenum typeOut, GLvoid* dataOut);

PARAMETERS

format
    Specifies the format of the pixel data. The following symbolic values are valid: GLU_COLOR_INDEX, GLU_STENCIL_INDEX, GLU_DEPTH_COMPONENT, GLU_RED, GLU_GREEN, GLU_BLUE, GLU_ALPHA, GLU_RGB, GLU_RGBA, GLU_BGR, GLU_BGRA, GLU_LUMINANCE, and GLU_LUMINANCE_ALPHA.

wIn, hIn
    Specify in pixels the width and height, respectively, of the source image.

typeIn
    Specifies the data type for dataIn. Must be one of GLU_UNSIGNED_BYTE, GLU_BYTE, GLU_BITMAP, GLU_UNSIGNED_SHORT, GLU_SHORT, GLU_UNSIGNED_INT, GLU_INT, GLU_FLOAT, GLU_UNSIGNED_BYTE_3_3_2, GLU_UNSIGNED_BYTE_2_3_3_REV, GLU_UNSIGNED_SHORT_5_6_5, GLU_UNSIGNED_SHORT_5_6_5_REV, GLU_UNSIGNED_SHORT_4_4_4_4, GLU_UNSIGNED_SHORT_4_4_4_4_REV, GLU_UNSIGNED_SHORT_5_5_5_1, GLU_UNSIGNED_SHORT_1_5_5_5_REV, GLU_UNSIGNED_INT_8_8_8_8, GLU_UNSIGNED_INT_8_8_8_8_REV, GLU_UNSIGNED_INT_10_10_10_2, or GLU_UNSIGNED_INT_2_10_10_10_REV.

dataIn
    Specifies a pointer to the source image.

wOut, hOut
    Specify the width and height, respectively, in pixels of the destination image.

typeOut
    Specifies the data type for dataOut. Must be one of GLU_UNSIGNED_BYTE, GLU_BYTE, GLU_BITMAP, GLU_UNSIGNED_SHORT, GLU_SHORT, GLU_UNSIGNED_INT, GLU_INT, GLU_FLOAT, GLU_UNSIGNED_BYTE_3_3_2, GLU_UNSIGNED_BYTE_2_3_3_REV, GLU_UNSIGNED_SHORT_5_6_5, GLU_UNSIGNED_SHORT_5_6_5_REV, GLU_UNSIGNED_SHORT_4_4_4_4, GLU_UNSIGNED_SHORT_4_4_4_4_REV, GLU_UNSIGNED_SHORT_5_5_5_1, GLU_UNSIGNED_SHORT_1_5_5_5_REV, GLU_UNSIGNED_INT_8_8_8_8, GLU_UNSIGNED_INT_8_8_8_8_REV, GLU_UNSIGNED_INT_10_10_10_2, or GLU_UNSIGNED_INT_2_10_10_10_REV.

dataOut
    Specifies a pointer to the destination image.

DESCRIPTION

gluScaleImage scales a pixel image using the appropriate pixel store modes to unpack data from the source image and pack data into the destination image.

When shrinking an image, gluScaleImage uses a box filter to sample the source image and create pixels for the destination image. When magnifying an image, the pixels from the source image are linearly interpolated to create the destination image.

A return value of zero indicates success, otherwise a GLU error code is returned (see gluErrorString()).

See the glReadPixels() reference page for a description of the acceptable values for the format, typeIn, and typeOut parameters.

NOTES

Formats GLU_BGR, and GLU_BGRA, and types GLU_UNSIGNED_BYTE_3_3_2, GLU_UNSIGNED_BYTE_2_3_3_REV, GLU_UNSIGNED_SHORT_5_6_5, GLU_UNSIGNED_SHORT_5_6_5_REV, GLU_UNSIGNED_SHORT_4_4_4_4, GLU_UNSIGNED_SHORT_4_4_4_4_REV, GLU_UNSIGNED_SHORT_5_5_5_1, GLU_UNSIGNED_SHORT_1_5_5_5_REV, GLU_UNSIGNED_INT_8_8_8_8, GLU_UNSIGNED_INT_8_8_8_8_REV, GLU_UNSIGNED_INT_10_10_10_2, and GLU_UNSIGNED_INT_2_10_10_10_REV are only available if the GL version is 1.2 or greater.

ERRORS

GLU_INVALID_VALUE is returned if wIn, hIn, wOut, or hOut is negative.

GLU_INVALID_ENUM is returned if format, typeIn, or typeOut is not legal.

GLU_INVALID_OPERATION is returned if typeIn or typeOut is GLU_UNSIGNED_BYTE_3_3_2 or GLU_UNSIGNED_BYTE_2_3_3_REV and format is not GLU_RGB.

GLU_INVALID_OPERATION is returned if typeIn or typeOut is GLU_UNSIGNED_SHORT_5_6_5 or GLU_UNSIGNED_SHORT_5_6_5_REV and format is not GLU_RGB.

GLU_INVALID_OPERATION is returned if typeIn or typeOut is GLU_UNSIGNED_SHORT_4_4_4_4 or GLU_UNSIGNED_SHORT_4_4_4_4_REV and format is neither GLU_RGBA nor GLU_BGRA.

GLU_INVALID_OPERATION is returned if typeIn or typeOut is GLU_UNSIGNED_SHORT_5_5_5_1 or GLU_UNSIGNED_SHORT_1_5_5_5_REV and format is neither GLU_RGBA nor GLU_BGRA.

GLU_INVALID_OPERATION is returned if typeIn or typeOut is GLU_UNSIGNED_INT_8_8_8_8 or GLU_UNSIGNED_INT_8_8_8_8_REV and format is neither GLU_RGBA nor GLU_BGRA.

GLU_INVALID_OPERATION is returned if typeIn or typeOut is GLU_UNSIGNED_INT_10_10_10_2 or GLU_UNSIGNED_INT_2_10_10_10_REV and format is neither GLU_RGBA nor GLU_BGRA.

SEE ALSO

gluBuild1DMipmaps(), gluBuild2DMipmaps(), gluBuild3DMipmaps(), gluErrorString(), glDrawPixels(), glReadPixels()

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/.