gluScaleImage Subroutine

OpenGL 1.2 for AIX: Reference Manual

gluScaleImage Subroutine

Purpose

Scales an image to an arbitrary size.

Library

OpenGL C bindings library: libGL.a

C Syntax

GLint gluScaleImage( GLenum format, 
   GLsizei wIn, 
   GLsizei hIn, 
   GLenum typeIn, 
   const void *dataIn, 
   GLsizei wOut, 
   GLsizei hOut, 
   GLenum typeOut, 
   void* dataOut)

Description

The gluScaleImage subroutine 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, the gluScaleImage subroutine 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 interpolated linearly to create the destination image.

A return value of zero indicates success; otherwise, a GLU error code is returned. (See the gluErrorString subroutine for standard GLU error codes.)

See the glReadPixels subroutine for a description of valid values for the format, typeIn, and typeOut parameters.

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_BGRA GL_LUMINANCE GL_LUMINANCE_ALPHA
wIn, hIn	Specify the width and height, respectively, of the source image that is scaled. Values are listed in map pixels.
typeIn	Specifies the data type for the dataIn parameter. The following symbolic values are valid: 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 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 the dataOut parameter. The following symbolic values are valid: 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 GL_UNSIGNED_INT_2_10_10_10_REV
dataOut	Specifies a pointer to the destination image.

See the glReadPixels subroutine for a description of valid values for the Format, TypeIn, and TypeOut parameters.

Return Values

0	Indicates the scaling succeeded. If the subroutine fails, a GLU error code is returned. (See the gluErrorString subroutine for standard GLU error codes.)

Error Codes

GLU_INVALID_VALUE is returned if wIn, hIn, wOut or hOut is Negative.
GLU_INVALID_ENUM is returned if format, typeIn or typeOut are 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.
GLU_INVALID_OPERATION is returned if typeIn or typeOut is GL_UNSIGNED_INT_8_8_8_8 or GL_UNSIGNED_INT_8_8_8_8_REV and format is neither GL_RGBA nor GL_BGRA.
GLU_INVALID_OPERATION is returned if typeIn or typeOut is GL_UNSIGNED_INT_10_10_10_2 or GL_UNSIGNED_INT_2_10_10_10_REV and format is neither GL_RGBA nor GL_BGRA.

Files

/usr/include/GL/gl.h

Contains C language constraints, variable type definitions, and ANSI function prototypes for OpenGL.

Related Information

The glDrawPixels subroutine, glReadPixels subroutine, gluBuild1DMipmaps subroutine, gluBuild2DMipmaps subroutine, gluBuild3DMipmaps subroutine, gluErrorString subroutine.

OpenGL Overview.