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 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_BGR, GL_BGRA, GL_LUMINANCE, and
GL_LUMINANCE_ALPHA.
wIn, hIn Specify in pixels the width and height, respec-
tively, of the source image.
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, GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2,
GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5,
GL_UNSIGNED_SHORT_5_6_5_REV,
GL_UNSIGNED_SHORT_4_4_4_4,
GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1,
GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8,
GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, and
GL_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 GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT,
GL_INT, GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2,
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 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 GL_BGR, and GL_BGRA, and types
GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_5_6_5_REV,
GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, and
GL_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
GL_UNSIGNED_BYTE_3_3_2 or GL_UNSIGNED_BYTE_2_3_3_REV and
format is not GL_RGB.
GLU_INVALID_OPERATION is returned if typeIn or typeOut is
GL_UNSIGNED_SHORT_5_6_5 or GL_UNSIGNED_SHORT_5_6_5_REV and
format is not GL_RGB.
GLU_INVALID_OPERATION is returned if typeIn or typeOut is
GL_UNSIGNED_SHORT_4_4_4_4 or GL_UNSIGNED_SHORT_4_4_4_4_REV
and format is neither GL_RGBA nor GL_BGRA.
GLU_INVALID_OPERATION is returned if typeIn or typeOut is
GL_UNSIGNED_SHORT_5_5_5_1 or GL_UNSIGNED_SHORT_1_5_5_5_REV
and format is neither GL_RGBA nor GL_BGRA.
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