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/*
# (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 <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 };
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