gluScaleImage

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: 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

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

A return value of 0 indicates success. Otherwise gluScaleImage returns a GLU error code that indicates what the problem is (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, r hOut is negative.
• GLU_INVALID_ENUM is returned if format, typeIn, or typeOut is not one of the accepted values.

See Also