gluScaleImage.3gl

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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Last Edited: Mon, May 22, 1995

AFV