1 files changed, 143 insertions, 0 deletions
diff --git a/v4l2-apps/libv4l/libv4lconvert/processing/whitebalance.c b/v4l2-apps/libv4l/libv4lconvert/processing/whitebalance.c
new file mode 100644
index 000000000..f5bfd961c
--- /dev/null
+++ b/v4l2-apps/libv4l/libv4lconvert/processing/whitebalance.c
@@ -0,0 +1,143 @@
+/*
+#             (C) 2008-2009 Elmar Kleijn <elmar_kleijn@hotmail.com>
+#             (C) 2008-2009 Sjoerd Piepenbrink <need4weed@gmail.com>
+#             (C) 2008-2009 Hans de Goede <hdegoede@redhat.com>
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser 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 <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <syscall.h>
+#include <unistd.h>
+#include "libv4lprocessing.h"
+#include "libv4lprocessing-priv.h"
+#include "../libv4lconvert-priv.h" /* for PIX_FMT defines */
+
+#define CLIP(color) (unsigned char)(((color)>0xff)?0xff:(((color)<0)?0:(color)))
+
+static int whitebalance_active(struct v4lprocessing_data *data) {
+  return v4lcontrol_get_ctrl(data->control, V4LCONTROL_WHITEBALANCE);
+}
+
+static int whitebalance_calculate_lookup_tables_bayer(
+  struct v4lprocessing_data *data, unsigned char *buf,
+  const struct v4l2_format *fmt, int starts_with_green)
+{
+  int x, y, a1 = 0, a2 = 0, b1 = 0, b2 = 0;
+  int green_avg, comp1_avg, comp2_avg, avg_avg;
+
+  for (y = 0; y < fmt->fmt.pix.height; y += 2) {
+    for (x = 0; x < fmt->fmt.pix.width; x += 2) {
+      a1 += *buf++;
+      a2 += *buf++;
+    }
+    buf += fmt->fmt.pix.bytesperline - fmt->fmt.pix.width;
+    for (x = 0; x < fmt->fmt.pix.width; x += 2) {
+      b1 += *buf++;
+      b2 += *buf++;
+    }
+    buf += fmt->fmt.pix.bytesperline - fmt->fmt.pix.width;
+  }
+
+  if (starts_with_green) {
+    green_avg = (a1 + b2) / 512;
+    comp1_avg = a2 / 256;
+    comp2_avg = b1 / 256;
+  } else {
+    green_avg = (a2 + b1) / 512;
+    comp1_avg = a1 / 256;
+    comp2_avg = b2 / 256;
+  }
+
+  x = fmt->fmt.pix.width * fmt->fmt.pix.height / 64;
+  if (abs(green_avg - comp1_avg) < x &&
+      abs(green_avg - comp2_avg) < x &&
+      abs(comp1_avg - comp2_avg) < x)
+    return 0;
+
+  avg_avg = (green_avg + comp1_avg + comp2_avg) / 3;
+
+  for (x = 0; x < 256; x++) {
+    data->comp1[x] = CLIP(data->comp1[x] * avg_avg / comp1_avg);
+    data->green[x] = CLIP(data->green[x] * avg_avg / green_avg);
+    data->comp2[x] = CLIP(data->comp2[x] * avg_avg / comp2_avg);
+  }
+
+  return 1;
+}
+
+static int whitebalance_calculate_lookup_tables_rgb(
+  struct v4lprocessing_data *data, unsigned char *buf,
+  const struct v4l2_format *fmt)
+{
+  int x, y, green_avg = 0, comp1_avg = 0, comp2_avg = 0, avg_avg;
+
+  for (y = 0; y < fmt->fmt.pix.height; y++) {
+    for (x = 0; x < fmt->fmt.pix.width; x++) {
+      comp1_avg += *buf++;
+      green_avg += *buf++;
+      comp2_avg += *buf++;
+    }
+    buf += fmt->fmt.pix.bytesperline - fmt->fmt.pix.width * 3;
+  }
+
+  x = fmt->fmt.pix.width * fmt->fmt.pix.height * 4;
+  if (abs(green_avg - comp1_avg) < x &&
+      abs(green_avg - comp2_avg) < x &&
+      abs(comp1_avg - comp2_avg) < x)
+    return 0;
+
+  /* scale to avoid integer overflows */
+  green_avg /= 256;
+  comp1_avg /= 256;
+  comp2_avg /= 256;
+  avg_avg = (green_avg + comp1_avg + comp2_avg) / 3;
+
+  for (x = 0; x < 256; x++) {
+    data->comp1[x] = CLIP(data->comp1[x] * avg_avg / comp1_avg);
+    data->green[x] = CLIP(data->green[x] * avg_avg / green_avg);
+    data->comp2[x] = CLIP(data->comp2[x] * avg_avg / comp2_avg);
+  }
+
+  return 1;
+}
+
+
+static int whitebalance_calculate_lookup_tables(
+  struct v4lprocessing_data *data,
+  unsigned char *buf, const struct v4l2_format *fmt)
+{
+  switch (fmt->fmt.pix.pixelformat) {
+    case V4L2_PIX_FMT_SGBRG8:
+    case V4L2_PIX_FMT_SGRBG8: /* Bayer patterns starting with green */
+      return whitebalance_calculate_lookup_tables_bayer(data, buf, fmt, 1);
+
+    case V4L2_PIX_FMT_SBGGR8:
+    case V4L2_PIX_FMT_SRGGB8: /* Bayer patterns *NOT* starting with green */
+      return whitebalance_calculate_lookup_tables_bayer(data, buf, fmt, 0);
+
+    case V4L2_PIX_FMT_RGB24:
+    case V4L2_PIX_FMT_BGR24:
+      return whitebalance_calculate_lookup_tables_rgb(data, buf, fmt);
+  }
+
+  return 0; /* Should never happen */
+}
+
+struct v4lprocessing_filter whitebalance_filter = {
+  whitebalance_active, whitebalance_calculate_lookup_tables };