Files
veejay/veejay-current/veejay-server/libvje/effects/gamma.c
2015-11-05 23:39:05 +01:00

76 lines
2.2 KiB
C

/*
* Linux VeeJay
*
* Copyright(C)2002 Niels Elburg <elburg@hio.hen.nl>
*
* 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
* 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 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 <stdint.h>
#include <stdio.h>
#include <libvjmem/vjmem.h>
#include "gamma.h"
#include <math.h>
static int gamma_flag = 0;
static uint8_t table[256];
vj_effect *gamma_init(int w, int h)
{
vj_effect *ve = (vj_effect *) vj_calloc(sizeof(vj_effect));
ve->num_params = 1;
ve->defaults = (int *) vj_calloc(sizeof(int) * ve->num_params); /* default values */
ve->limits[0] = (int *) vj_calloc(sizeof(int) * ve->num_params); /* min */
ve->limits[1] = (int *) vj_calloc(sizeof(int) * ve->num_params); /* max */
ve->defaults[0] = 124;
ve->limits[0][0] = 0;
ve->limits[1][0] = 500;
ve->description = "Gamma Correction";
ve->extra_frame = 0;
ve->sub_format = -1;
ve->has_user = 0;
ve->param_description = vje_build_param_list(ve->num_params, "Gamma");
ve->parallel = 1;
return ve;
}
static void gamma_setup(int width, int height,
double gamma_value)
{
int i;
double val;
for (i = 0; i < 256; i++) {
val = i / 256.0;
val = pow(val, gamma_value);
val = 256.0 * val;
table[i] = val;
}
}
void gamma_apply(VJFrame *frame, int width,
int height, int gamma_value)
{
unsigned int i, len = frame->len;
uint8_t *Y = frame->data[0];
/* gamma correction YCbCr, only on luminance not on chroma */
if (gamma_value != gamma_flag)
gamma_setup(width, height, (double) (gamma_value / 100.0));
for (i = 0; i < len; i++) {
Y[i] = (uint8_t) table[Y[i]];
}
}
void gamma_free(){}