1 /*

     2     SDL - Simple DirectMedia Layer

     3     Copyright (C) 1997-2006 Sam Lantinga

     4 

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

     6     modify it under the terms of the GNU Lesser General Public

     7     License as published by the Free Software Foundation; either

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

     9 

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

    11     but WITHOUT ANY WARRANTY; without even the implied warranty of

    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    13     Lesser General Public License for more details.

    14 

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

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

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

    18 

    19     Sam Lantinga

    20     slouken@libsdl.org

    21 */

    22 #include "SDL_config.h"

    23 

    24 #include "SDL.h"

    25 #include "SDL_events.h"

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

    27 #include "SDL_x11video.h"

    28 

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

    30 #define MAX_GAMMA 10.0

    31 #define MIN_GAMMA (1.0/MAX_GAMMA)

    32 

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

    34 {

    35 #if SDL_VIDEO_DRIVER_X11_VIDMODE

    36     if (use_vidmode >= 200) {

    37         SDL_NAME(XF86VidModeGamma) gamma;

    38         Bool succeeded;

    39 

    40 	/* Clamp the gamma values */

    41 	if ( red < MIN_GAMMA ) {

    42 		gamma.red = MIN_GAMMA;

    43 	} else

    44 	if ( red > MAX_GAMMA ) {

    45 		gamma.red = MAX_GAMMA;

    46 	} else {

    47         	gamma.red = red;

    48 	}

    49 	if ( green < MIN_GAMMA ) {

    50 		gamma.green = MIN_GAMMA;

    51 	} else

    52 	if ( green > MAX_GAMMA ) {

    53 		gamma.green = MAX_GAMMA;

    54 	} else {

    55         	gamma.green = green;

    56 	}

    57 	if ( blue < MIN_GAMMA ) {

    58 		gamma.blue = MIN_GAMMA;

    59 	} else

    60 	if ( blue > MAX_GAMMA ) {

    61 		gamma.blue = MAX_GAMMA;

    62 	} else {

    63         	gamma.blue = blue;

    64 	}

    65         if ( SDL_GetAppState() & SDL_APPACTIVE ) {

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

    67             XSync(SDL_Display, False);

    68         } else {

    69             gamma_saved[0] = gamma.red;

    70             gamma_saved[1] = gamma.green;

    71             gamma_saved[2] = gamma.blue;

    72             succeeded = True;

    73         }

    74         if ( succeeded ) {

    75             ++gamma_changed;

    76         }

    77         return succeeded ? 0 : -1;

    78     }

    79 #endif

    80     SDL_SetError("Gamma correction not supported");

    81     return -1;

    82 }

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

    84 {

    85     int result;

    86 

    87     SDL_Lock_EventThread();

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

    89     SDL_Unlock_EventThread();

    90 

    91     return(result);

    92 }

    93 

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

    95 {

    96 #if SDL_VIDEO_DRIVER_X11_VIDMODE

    97     if (use_vidmode >= 200) {

    98         SDL_NAME(XF86VidModeGamma) gamma;

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

   100             *red   = gamma.red;

   101             *green = gamma.green;

   102             *blue  = gamma.blue;

   103             return 0;

   104         }

   105         return -1;

   106     }

   107 #endif

   108     return -1;

   109 }

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

   111 {

   112     int result;

   113 

   114     SDL_Lock_EventThread();

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

   116     SDL_Unlock_EventThread();

   117 

   118     return(result);

   119 }

   120 

   121 void X11_SaveVidModeGamma(_THIS)

   122 {

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

   124     if ( X11_GetGammaNoLock(this,

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

   126         this->SetGamma = 0;

   127         this->GetGamma = 0;

   128     }

   129     gamma_changed = 0;

   130 }

   131 void X11_SwapVidModeGamma(_THIS)

   132 {

   133     float new_gamma[3];

   134 

   135     if ( gamma_changed ) {

   136         new_gamma[0] = gamma_saved[0];

   137         new_gamma[1] = gamma_saved[1];

   138         new_gamma[2] = gamma_saved[2];

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

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

   141     }

   142 }