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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 
X11_SetGammaNoLock(_THIS,float red,float green,float blue)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 }
X11_SetVidModeGamma(_THIS,float red,float green,float blue)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 
X11_GetGammaNoLock(_THIS,float * red,float * green,float * blue)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 }
X11_GetVidModeGamma(_THIS,float * red,float * green,float * blue)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 
X11_SaveVidModeGamma(_THIS)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 }
X11_SwapVidModeGamma(_THIS)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 }
143