Add gamma support to ply-image.

src/ply-gamma.c

+/* ply-gamma.c - plymouth gamma setup via KMS
+ *
+ * Copyright (C) 2011, The Chromium OS Authors.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#include "ply-gamma.h"
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+static const int kInternalPanel = 1;
+
+typedef struct {
+  uint16_t *red;
+  uint16_t *green;
+  uint16_t *blue;
+} GammaRamp;
+
+static GammaRamp* load_gamma_ramp(const char* file) {
+  const int kGammaSize = 256;
+  int i, r = 0;
+
+  FILE* f = fopen(file, "rb");
+  if (!f)
+    return NULL;
+
+  unsigned char red[kGammaSize], green[kGammaSize], blue[kGammaSize];
+
+  r += fread(red, sizeof(red), 1, f);
+  r += fread(green, sizeof(green), 1, f);
+  r += fread(blue, sizeof(blue), 1, f);
+  fclose(f);
+
+  if (r != 3)
+    return NULL;
+
+  GammaRamp* ramp = (GammaRamp*)malloc(sizeof(GammaRamp));
+  ramp->red = (uint16_t*)malloc(sizeof(uint16_t) * kGammaSize);
+  ramp->green = (uint16_t*)malloc(sizeof(uint16_t) * kGammaSize);
+  ramp->blue = (uint16_t*)malloc(sizeof(uint16_t) * kGammaSize);
+
+  for(i = 0; i < kGammaSize; ++i) {
+    ramp->red[i]   = (uint16_t)red[i] * 257;
+    ramp->green[i] = (uint16_t)green[i] * 257;
+    ramp->blue[i]  = (uint16_t)blue[i] * 257;
+  }
+
+  return ramp;
+}
+
+static void free_gamma_ramp(GammaRamp* ramp) {
+  free(ramp->red);
+  free(ramp->green);
+  free(ramp->blue);
+  free(ramp);
+}
+
+bool ply_gamma_set(const char* file) {
+  int r;
+  drmModeCrtcPtr mode;
+  GammaRamp* ramp;
+
+  ramp = load_gamma_ramp(file);
+
+  if (!ramp) {
+    fprintf(stderr, "Unable to load gamma ramp\n");
+    return false;
+  }
+
+  int fd = drmOpen("i915", NULL);
+  if (fd < 0) {
+    fprintf(stderr, "Unable to open i915 drm\n");
+    return false;
+  }
+
+  drmModeRes *resources = drmModeGetResources(fd);
+  if (!resources) {
+    fprintf(stderr, "Unable to get mode resources\n");
+    drmClose(fd);
+    return false;
+  }
+
+  mode = drmModeGetCrtc(fd, resources->crtcs[kInternalPanel]);
+  r = drmModeCrtcSetGamma(fd,
+                           mode->crtc_id,
+                           mode->gamma_size,
+                           ramp->red,
+                           ramp->green,
+                           ramp->blue);
+
+  drmModeFreeResources(resources);
+  drmClose(fd);
+  free_gamma_ramp(ramp);
+  return r >= 0;
+}