gluScaleImage

NAME

gluScaleImage -- scale an image to an arbitrary size

C SPECIFICATION

int gluScaleImage(GLenum format,
                  GLint widthin,
                  GLint heightin,
                  GLenum typein,
                  const void *datain,
                  GLint widthout,
                  GLint heightout,
                  GLenum typeout,
                  void *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.

widthin, heightin
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.

widthout, heightout
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 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 indicating what the problem was (see gluErrorString).

Please refer to the glReadPixels reference page for a description of the acceptable values for the format, typein, and typeout parameters.

SEE ALSO

glDrawPixels, glReadPixels, gluBuild1DMipmaps, gluBuild2DMipmaps, gluErrorString


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© 1995 Uwe Behrens All rights reserved