gluScaleImage - scale an image to an arbitrary size
GLint gluScaleImage( | GLenum | format, |
| GLsizei | wIn, | |
| GLsizei | hIn, | |
| GLenum | typeIn, | |
| const void* | dataIn, | |
| GLsizei | wOut, | |
| GLsizei | hOut, | |
| GLenum | typeOut, | |
| GLvoid* | dataOut); |
format
Specifies the format of the pixel data.
The following symbolic values are valid:
GL_RGB,
GL_RGBA,
GL_LUMINANCE, and
GL_LUMINANCE_ALPHA.
wIn, hInSpecify in pixels the width and height, respectively, of the source image.
typeIn
Specifies the data type for dataIn. Must be one of
GL_UNSIGNED_BYTE,
GL_UNSIGNED_SHORT_5_6_5,
GL_UNSIGNED_SHORT_4_4_4_4, or
GL_UNSIGNED_SHORT_5_5_5_1.
dataInSpecifies a pointer to the source image.
wOut, hOutSpecify the width and height, respectively, in pixels of the destination image.
typeOut
Specifies the data type for dataOut. Must be one of
GL_UNSIGNED_BYTE,
GL_UNSIGNED_SHORT_5_6_5,
GL_UNSIGNED_SHORT_4_4_4_4, or
GL_UNSIGNED_SHORT_5_5_5_1.
dataOutSpecifies a pointer to the destination image.
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.
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
GL_UNSIGNED_SHORT_5_6_5
and format is not GL_RGB.
GLU_INVALID_OPERATION is returned if typeIn or typeOut is
GL_UNSIGNED_SHORT_4_4_4_4
and format is not GL_RGBA.
GLU_INVALID_OPERATION is returned if typeIn or typeOut is
GL_UNSIGNED_SHORT_5_5_5_1
and format is not GL_RGBA.
Copyright c 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/.