/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#include "SDL.h"

#include "SDL_events.h"

#include "../../events/SDL_events_c.h"

#include "SDL_x11video.h"

/* From the X server sources... */

#define MAX_GAMMA 10.0

#define MIN_GAMMA (1.0/MAX_GAMMA)

static int X11_SetGammaNoLock(_THIS, float red, float green, float blue)

{

#if SDL_VIDEO_DRIVER_X11_VIDMODE

    if (use_vidmode >= 200) {

        SDL_NAME(XF86VidModeGamma) gamma;

        Bool succeeded;

	/* Clamp the gamma values */

	if ( red < MIN_GAMMA ) {

		gamma.red = MIN_GAMMA;

	} else

	if ( red > MAX_GAMMA ) {

		gamma.red = MAX_GAMMA;

	} else {

        	gamma.red = red;

	}

	if ( green < MIN_GAMMA ) {

		gamma.green = MIN_GAMMA;

	} else

	if ( green > MAX_GAMMA ) {

		gamma.green = MAX_GAMMA;

	} else {

        	gamma.green = green;

	}

	if ( blue < MIN_GAMMA ) {

		gamma.blue = MIN_GAMMA;

	} else

	if ( blue > MAX_GAMMA ) {

		gamma.blue = MAX_GAMMA;

	} else {

        	gamma.blue = blue;

	}

        if ( SDL_GetAppState() & SDL_APPACTIVE ) {

            succeeded = SDL_NAME(XF86VidModeSetGamma)(SDL_Display, SDL_Screen, &gamma);

            XSync(SDL_Display, False);

        } else {

            gamma_saved[0] = gamma.red;

            gamma_saved[1] = gamma.green;

            gamma_saved[2] = gamma.blue;

            succeeded = True;

        }

        if ( succeeded ) {

            ++gamma_changed;

        }

        return succeeded ? 0 : -1;

    }

#endif

    SDL_SetError("Gamma correction not supported");

    return -1;

}

int X11_SetVidModeGamma(_THIS, float red, float green, float blue)

{

    int result;

    SDL_Lock_EventThread();

    result = X11_SetGammaNoLock(this, red, green, blue);

    SDL_Unlock_EventThread();

    return(result);

}

static int X11_GetGammaNoLock(_THIS, float *red, float *green, float *blue)

{

#if SDL_VIDEO_DRIVER_X11_VIDMODE

    if (use_vidmode >= 200) {

        SDL_NAME(XF86VidModeGamma) gamma;

        if (SDL_NAME(XF86VidModeGetGamma)(SDL_Display, SDL_Screen, &gamma)) {

            *red   = gamma.red;

            *green = gamma.green;

            *blue  = gamma.blue;

            return 0;

        }

        return -1;

    }

#endif

    return -1;

}

int X11_GetVidModeGamma(_THIS, float *red, float *green, float *blue)

{

    int result;

    SDL_Lock_EventThread();

    result = X11_GetGammaNoLock(this, red, green, blue);

    SDL_Unlock_EventThread();

    return(result);

}

void X11_SaveVidModeGamma(_THIS)

{

    /* Try to save the current gamma, otherwise disable gamma control */

    if ( X11_GetGammaNoLock(this,

              &gamma_saved[0], &gamma_saved[1], &gamma_saved[2]) < 0 ) {

        this->SetGamma = 0;

        this->GetGamma = 0;

    }

    gamma_changed = 0;

}

void X11_SwapVidModeGamma(_THIS)

{

    float new_gamma[3];

    if ( gamma_changed ) {

        new_gamma[0] = gamma_saved[0];

        new_gamma[1] = gamma_saved[1];

        new_gamma[2] = gamma_saved[2];

        X11_GetGammaNoLock(this, &gamma_saved[0], &gamma_saved[1], &gamma_saved[2]);

        X11_SetGammaNoLock(this, new_gamma[0], new_gamma[1], new_gamma[2]);

    }

}