beginning c binding

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 292 insertions, 0 deletions

diff --git a/src/blueshift_randr_c.c b/src/blueshift_randr_c.c
new file mode 100644
index 0000000..bf2656e
--- /dev/null
+++ b/src/blueshift_randr_c.c
@@ -0,0 +1,292 @@
+/**
+ * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, 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 Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#include <xcb/xcb.h>
+#include <xcb/randr.h>
+
+
+
+/**
+ * The major version of RANDR the program expects
+ */
+#define RANDR_VERSION_MAJOR  1U
+
+/**
+ * The minor version of RANDR the program expects
+ */
+#define RANDR_VERSION_MINOR  3U
+
+
+
+/**
+ * Data structure for CRTC caches
+ */
+typedef struct blueshift_randr_crtc
+{
+  /**
+   * Size of colour curves on the X-axis
+   */
+  unsigned int curve_size;
+  
+  /**
+   * CRT controller
+   */
+  xcb_randr_crtc_t* crtc;
+  
+} blueshift_randr_crtc_t;
+
+
+
+/**
+ * Connection to the X server
+ */
+static xcb_connection_t* connection;
+
+/**
+ * Used to store errors in
+ */
+static xcb_generic_error_t* error;
+
+/**
+ * Screen resources
+ */
+static xcb_randr_get_screen_resources_current_reply_t* res_reply;
+
+/**
+ * The first CRTC
+ */
+static blueshift_randr_crtc_t* crtcs;
+
+/**
+ * The CRTC after the last CRTC
+ */
+static blueshift_randr_crtc_t* crtcs_end;
+
+/**
+ * The red colour curve
+ */
+static uint16_t* r_curve;
+
+/**
+ * The green colour curve
+ */
+static uint16_t* g_curve;
+
+/**
+ * The blue colour curve
+ */
+static uint16_t* b_curve;
+
+
+
+/**
+ * Start stage of colour curve control
+ * 
+ * @param   use_screen  The screen to use
+ * @return              Zero on success
+ */
+int blueshift_randr_open(int use_screen)
+{
+  blueshift_randr_crtc_t* crtcs_;
+  
+  xcb_randr_query_version_cookie_t version_cookie;
+  xcb_randr_query_version_reply_t* randr_version;
+  const xcb_setup_t* setup;
+  xcb_screen_iterator_t iter;
+  xcb_screen_t* screen;
+  xcb_randr_get_screen_resources_current_cookie_t res_cookie;
+  unsigned int crtc_count;
+  xcb_randr_get_crtc_gamma_size_cookie_t gamma_size_cookie;
+  xcb_randr_get_crtc_gamma_size_reply_t* gamma_size_reply;
+  xcb_randr_get_crtc_gamma_cookie_t gamma_get_cookie;
+  xcb_randr_get_crtc_gamma_reply_t* gamma_get_reply;
+  
+  
+  
+  /* Get X connection */
+  
+  connection = xcb_connect(NULL, &use_screen);
+  
+  
+  /* Check RANDR protocol version */
+  
+  version_cookie = xcb_randr_query_version(connection, RANDR_VERSION_MAJOR, RANDR_VERSION_MINOR);
+  randr_version = xcb_randr_query_version_reply(connection, version_cookie, &error);
+  
+  if (error || (randr_version == NULL))
+    {
+      fprintf(stderr, "RANDR version query returned %i", error ? error->error_code : -1);
+      xcb_disconnect(connection);
+      return 1;
+    }
+  
+  if (randr_version->major_version != RANDR_VERSION_MAJOR || randr_version->minor_version < RANDR_VERSION_MINOR)
+    {
+      fprintf(stderr, "Unsupported RANDR version, got %u.%u, expected %u.%u\n",
+	      randr_version->major_version, randr_version->minor_version,
+	      RANDR_VERSION_MAJOR, RANDR_VERSION_MINOR);
+      free(randr_version);
+      xcb_disconnect(connection);
+      return 1;
+    }
+  
+  free(randr_version);
+  
+  
+  /* Get X resources */
+  
+  setup = xcb_get_setup(connection);
+  iter = xcb_setup_roots_iterator(setup);
+  screen = iter.data;
+  
+  res_cookie = xcb_randr_get_screen_resources_current(connection, screen->root);
+  res_reply = xcb_randr_get_screen_resources_current_reply(connection, res_cookie, &error);
+  
+  if (error)
+    {
+      fprintf(stderr, "RANDR screen resource query returned %i\n", error->error_code);
+      xcb_disconnect(connection);
+      return 1;
+    }
+  
+  
+  /* Get CRTC:s */
+  
+  crtc_count = res_reply->num_crtcs;
+  crtcs = malloc(crtc_count * sizeof(blueshift_randr_crtc_t));
+  crtcs->crtc = xcb_randr_get_screen_resources_current_crtcs(res_reply);
+  crtcs_end = crtcs + crtc_count;
+  
+  
+  /* Prepare CRTC:s */
+  
+  for (crtcs_ = crtcs; crtcs_ != crtcs_end; crtcs_++)
+    {
+      /* Set CRTC */
+      
+      if (crtcs_ != crtcs)
+	crtcs_->crtc = (crtcs_ - 1)->crtc + 1;
+      
+      
+      /* Get curve X-axis size */
+      
+      gamma_size_cookie = xcb_randr_get_crtc_gamma_size(connection, *(crtcs_->crtc));
+      gamma_size_reply = xcb_randr_get_crtc_gamma_size_reply(connection, gamma_size_cookie, &error);
+      
+      if (error)
+	{
+	  fprintf(stderr, "RANDR CRTC gamma size query returned %i\n", error->error_code);
+	  xcb_disconnect(connection);
+	  return 1;
+	}
+      
+      crtcs_->curve_size = gamma_size_reply->size;
+      free(gamma_size_reply);
+      
+      
+      /* Acquire curve control */
+      
+      gamma_get_cookie = xcb_randr_get_crtc_gamma(connection, *(crtcs_->crtc));
+      gamma_get_reply = xcb_randr_get_crtc_gamma_reply(connection, gamma_get_cookie, &error);
+      
+      if (error)
+	{
+	  fprintf(stderr, "RANDR CRTC gamma query returned %i\n", error->error_code);
+	  xcb_disconnect(connection);
+	  return 1;
+	}
+      
+      free(gamma_get_reply);
+    }
+  
+  
+  /* Allocate curves */
+  
+  r_curve = malloc(3 * 256 * sizeof(uint16_t));
+  g_curve = r_curve + 256;
+  b_curve = g_curve + 256;
+  
+  return 0;
+}
+
+
+/**
+ * Apply stage of colour curve control
+ * 
+ * @param   use_crtcs  Mask of CRTC:s to use
+ * @param   r_curve    The red colour curve
+ * @param   g_curve    The green colour curve
+ * @param   b_curve    The blue colour curve
+ * @return             Zero on success
+ */
+int blueshift_randr_apply(uint64_t use_crtcs, uint16_t* r_curve, uint16_t* g_curve, uint16_t* b_curve)
+{
+  blueshift_randr_crtc_t* crtcs_ = crtcs;
+  
+  xcb_void_cookie_t gamma_set_cookie;
+  
+  
+  /* Use CRTC:s */
+  
+  while (crtcs_ != crtcs_end)
+    {
+      /* Check whether we should use the CRTC */
+
+      if ((use_crtcs & 1) == 0)
+	goto next_crtc;
+      
+      
+      /* Apply curves */
+      
+      gamma_set_cookie = xcb_randr_set_crtc_gamma_checked(connection, *(crtcs_->crtc), crtcs_->curve_size,
+							  r_curve, g_curve, b_curve);
+      error = xcb_request_check(connection, gamma_set_cookie);
+      
+      if (error)
+	{
+	  fprintf(stderr, "RANDR CRTC control returned %i\n", error->error_code);
+	  return 1;
+	}
+      
+      
+      /* Next CRTC */
+      
+    next_crtc:
+      crtcs_++;
+      use_crtcs >>= 1;
+    }
+  
+  return 0;
+}
+
+
+/**
+ * Resource freeing stage of colour curve control
+ */
+void blueshift_randr_close(void)
+{
+  /* Free remaining resources */
+  
+  free(r_curve);
+  free(crtcs);
+  free(res_reply);
+  xcb_disconnect(connection);
+}
+