sdl_setgammaramp(3) [suse man page]

SDL_SetGammaRamp(3)						 SDL API Reference					       SDL_SetGammaRamp(3)

NAME

       SDL_SetGammaRamp - Sets the color gamma lookup tables for the display

SYNOPSIS

       #include "SDL.h"

       int SDL_SetGammaRamp(Uint16 *redtable, Uint16 *greentable, Uint16 *bluetable);

DESCRIPTION

       Sets  the gamma lookup tables for the display for each color component. Each table is an array of 256 Uint16 values, representing a mapping
       between the input and output for that channel. The input is the index into the array, and the output is the  16-bit  gamma  value  at  that
       index, scaled to the output color precision. You may pass NULL to any of the channels to leave them unchanged.

       This  function  adjusts the gamma based on lookup tables, you can also have the gamma calculated based on a "gamma function" parameter with
       SDL_SetGamma.

       Not all display hardware is able to change gamma.

RETURN VALUE

       Returns -1 on error (or if gamma adjustment is not supported).

SEE ALSO

       SDL_SetGamma SDL_GetGammaRamp

SDL
							      Tue 11 Sep 2001, 23:01					       SDL_SetGammaRamp(3)

pfsgamma(1)						      General Commands Manual						       pfsgamma(1)

NAME

       pfsgamma - Apply gamma correction to color or gray-scale images

SYNOPSIS

       pfsgamma [--gamma <gamma> | --inverse-gamma <inv-gamma>] [--mul <multiplier>]

DESCRIPTION

       Use  this  command  to  gamma correct a stream of pfs images. Gamma correction is equivalent to raising value of R, G and B (or Y for gray-
       scale images) channels to 1/gamma power. More information on gamma correction can be found at:

       http://www.poynton.com/notes/colour_and_gamma/GammaFAQ.html

       This command can work on color images, in which case XYZ channels are transformed to RGB space, then they are gamma corrected  before  they
       are converted back to XYZ. For gray-scale images (only Y channel and XZ missing) gamma correction is applied only to Y channel.

       Data can be multiplied by an optional multiplier before gamma correction.

       Note:  gamma  correction  will set the 'LUMINANCE' tag to 'DISPLAY' thus cancelling any sRGB correction when saving to LDR files (like PPM,
       TIFF). This will also cause a warning message when saving to HDR files, because the intensities after gamma  correction	are  not  linearly
       related to luminance any more.

OPTIONS

       --gamma <gamma>, -g <gamma>
	      Perform  gamma correction (input^(1/gamma)). This can be used to convert images from relative luminance or radiance to pixel values.
	      Default value: 1.0

       --inverse-gamma <inv-gamma>, -i <inv-gamma>
	      Perform inverse gamma correction (input^(gamma)). This can be used to convert images from pixel values to relative radiance or lumi-
	      nance.

       --mul <mul>, -m <mul>
	      Multiply data by this value before gamma correction. Default value: 1

EXAMPLES

       pfsin memorial.hdr | pfsgamma -g 1.8 -m 10 | pfsout memorial_gc.ppm

	      Multiply memorial image by 10, gamma correct it and save to memorial_gc.ppm.

SEE ALSO

       pfsin(1) pfsout(1) pfsdisplayfunction(1)

BUGS

       Please report bugs and comments to the pfstools discussion group (http://groups.google.com/group/pfstools).

																       pfsgamma(1)