1 /* gamma-w32gdi.c -- Windows GDI gamma adjustment source
2 This file is part of Redshift.
3
4 Redshift is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
8
9 Redshift is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with Redshift. If not, see <http://www.gnu.org/licenses/>.
16
17 Copyright (c) 2010-2017 Jon Lund Steffensen <jonlst@gmail.com>
18 */
19
20 #include <stdio.h>
21 #include <stdlib.h>
22
23 #ifndef WINVER
24 # define WINVER 0x0500
25 #endif
26 #include <windows.h>
27 #include <wingdi.h>
28
29 #ifdef ENABLE_NLS
30 # include <libintl.h>
31 # define _(s) gettext(s)
32 #else
33 # define _(s) s
34 #endif
35
36 #include "gamma-w32gdi.h"
37 #include "colorramp.h"
38
39 #define GAMMA_RAMP_SIZE 256
40 #define MAX_ATTEMPTS 10
41
42
43 typedef struct {
44 WORD *saved_ramps;
45 } w32gdi_state_t;
46
47
48 static int
w32gdi_init(w32gdi_state_t ** state)49 w32gdi_init(w32gdi_state_t **state)
50 {
51 *state = malloc(sizeof(w32gdi_state_t));
52 if (state == NULL) return -1;
53
54 w32gdi_state_t *s = *state;
55 s->saved_ramps = NULL;
56
57 return 0;
58 }
59
60 static int
w32gdi_start(w32gdi_state_t * state)61 w32gdi_start(w32gdi_state_t *state)
62 {
63 BOOL r;
64
65 /* Open device context */
66 HDC hDC = GetDC(NULL);
67 if (hDC == NULL) {
68 fputs(_("Unable to open device context.\n"), stderr);
69 return -1;
70 }
71
72 /* Check support for gamma ramps */
73 int cmcap = GetDeviceCaps(hDC, COLORMGMTCAPS);
74 if (cmcap != CM_GAMMA_RAMP) {
75 fputs(_("Display device does not support gamma ramps.\n"),
76 stderr);
77 return -1;
78 }
79
80 /* Allocate space for saved gamma ramps */
81 state->saved_ramps = malloc(3*GAMMA_RAMP_SIZE*sizeof(WORD));
82 if (state->saved_ramps == NULL) {
83 perror("malloc");
84 ReleaseDC(NULL, hDC);
85 return -1;
86 }
87
88 /* Save current gamma ramps so we can restore them at program exit */
89 r = GetDeviceGammaRamp(hDC, state->saved_ramps);
90 if (!r) {
91 fputs(_("Unable to save current gamma ramp.\n"), stderr);
92 ReleaseDC(NULL, hDC);
93 return -1;
94 }
95
96 /* Release device context */
97 ReleaseDC(NULL, hDC);
98
99 return 0;
100 }
101
102 static void
w32gdi_free(w32gdi_state_t * state)103 w32gdi_free(w32gdi_state_t *state)
104 {
105 /* Free saved ramps */
106 free(state->saved_ramps);
107
108 free(state);
109 }
110
111
112 static void
w32gdi_print_help(FILE * f)113 w32gdi_print_help(FILE *f)
114 {
115 fputs(_("Adjust gamma ramps with the Windows GDI.\n"), f);
116 fputs("\n", f);
117 }
118
119 static int
w32gdi_set_option(w32gdi_state_t * state,const char * key,const char * value)120 w32gdi_set_option(w32gdi_state_t *state, const char *key, const char *value)
121 {
122 if (strcasecmp(key, "preserve") == 0) {
123 fprintf(stderr, _("Parameter `%s` is now always on; "
124 " Use the `%s` command-line option"
125 " to disable.\n"),
126 key, "-P");
127 } else {
128 fprintf(stderr, _("Unknown method parameter: `%s'.\n"), key);
129 return -1;
130 }
131
132 return 0;
133 }
134
135 static void
w32gdi_restore(w32gdi_state_t * state)136 w32gdi_restore(w32gdi_state_t *state)
137 {
138 /* Open device context */
139 HDC hDC = GetDC(NULL);
140 if (hDC == NULL) {
141 fputs(_("Unable to open device context.\n"), stderr);
142 return;
143 }
144
145 /* Restore gamma ramps */
146 BOOL r = FALSE;
147 for (int i = 0; i < MAX_ATTEMPTS && !r; i++) {
148 /* We retry a few times before giving up because some
149 buggy drivers fail on the first invocation of
150 SetDeviceGammaRamp just to succeed on the second. */
151 r = SetDeviceGammaRamp(hDC, state->saved_ramps);
152 }
153 if (!r) fputs(_("Unable to restore gamma ramps.\n"), stderr);
154
155 /* Release device context */
156 ReleaseDC(NULL, hDC);
157 }
158
159 static int
w32gdi_set_temperature(w32gdi_state_t * state,const color_setting_t * setting,int preserve)160 w32gdi_set_temperature(
161 w32gdi_state_t *state, const color_setting_t *setting, int preserve)
162 {
163 BOOL r;
164
165 /* Open device context */
166 HDC hDC = GetDC(NULL);
167 if (hDC == NULL) {
168 fputs(_("Unable to open device context.\n"), stderr);
169 return -1;
170 }
171
172 /* Create new gamma ramps */
173 WORD *gamma_ramps = malloc(3*GAMMA_RAMP_SIZE*sizeof(WORD));
174 if (gamma_ramps == NULL) {
175 perror("malloc");
176 ReleaseDC(NULL, hDC);
177 return -1;
178 }
179
180 WORD *gamma_r = &gamma_ramps[0*GAMMA_RAMP_SIZE];
181 WORD *gamma_g = &gamma_ramps[1*GAMMA_RAMP_SIZE];
182 WORD *gamma_b = &gamma_ramps[2*GAMMA_RAMP_SIZE];
183
184 if (preserve) {
185 /* Initialize gamma ramps from saved state */
186 memcpy(gamma_ramps, state->saved_ramps,
187 3*GAMMA_RAMP_SIZE*sizeof(WORD));
188 } else {
189 /* Initialize gamma ramps to pure state */
190 for (int i = 0; i < GAMMA_RAMP_SIZE; i++) {
191 WORD value = (double)i/GAMMA_RAMP_SIZE *
192 (UINT16_MAX+1);
193 gamma_r[i] = value;
194 gamma_g[i] = value;
195 gamma_b[i] = value;
196 }
197 }
198
199 colorramp_fill(gamma_r, gamma_g, gamma_b, GAMMA_RAMP_SIZE,
200 setting);
201
202 /* Set new gamma ramps */
203 r = FALSE;
204 for (int i = 0; i < MAX_ATTEMPTS && !r; i++) {
205 /* We retry a few times before giving up because some
206 buggy drivers fail on the first invocation of
207 SetDeviceGammaRamp just to succeed on the second. */
208 r = SetDeviceGammaRamp(hDC, gamma_ramps);
209 }
210 if (!r) {
211 fputs(_("Unable to set gamma ramps.\n"), stderr);
212 free(gamma_ramps);
213 ReleaseDC(NULL, hDC);
214 return -1;
215 }
216
217 free(gamma_ramps);
218
219 /* Release device context */
220 ReleaseDC(NULL, hDC);
221
222 return 0;
223 }
224
225
226 const gamma_method_t w32gdi_gamma_method = {
227 "wingdi", 1,
228 (gamma_method_init_func *)w32gdi_init,
229 (gamma_method_start_func *)w32gdi_start,
230 (gamma_method_free_func *)w32gdi_free,
231 (gamma_method_print_help_func *)w32gdi_print_help,
232 (gamma_method_set_option_func *)w32gdi_set_option,
233 (gamma_method_restore_func *)w32gdi_restore,
234 (gamma_method_set_temperature_func *)w32gdi_set_temperature
235 };
236