GLUSCALEIMAGE() MachTen Programmer’s Manual GLUSCALEIMAGE()

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 )

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PARAMETERS
format Specifies the format of the pixel data. The fol-
lowing symbolic values are valid: GL_COLOR_INDEX,
GL_STENCIL_INDEX, GL_DEPTH_COMPONENT, GL_RED,
GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB, GL_RGBA,
GL_LUMINANCE, and GL_LUMINANCE_ALPHA.

wIn, hIn Specify the width and height, respectively, of
the source image that is scaled.

typeIn Specifies the data type for dataIn. Must be one
of GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT,
GL_INT, or GL_FLOAT.

dataIn Specifies a pointer to the source image.

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

typeOut Specifies the data type for dataOut. Must be one
of GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT,
GL_INT, or GL_FLOAT.

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 des-
tination image. When magnifying an image, the pixels from
the source image are linearly interpolated to create the
destination image.

A return value of 0 indicates success, otherwise a GLU
error code is returned (see gluErrorString).

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

ERRORS
GLU_INVALID_VALUE is returned if wIn, hIn, wOut, or hOut
are < 0.

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

SEE ALSO
glDrawPixels, glReadPixels, gluBuild1DMipmaps,
gluBuild2DMipmaps, gluErrorString

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