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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "readers.h"
#include "viewer.h"
#include "lut.h"
/* ----------------------------------------------------------------------- */
struct op_map_parm_ch op_map_nothing = {
gamma: 1,
bottom: 0,
top: 255,
left: 0,
right: 255
};
struct op_map_lut {
unsigned char red[256];
unsigned char green[256];
unsigned char blue[256];
};
/* ----------------------------------------------------------------------- */
/* functions */
static void build_lut(struct op_map_parm_ch *arg, unsigned char *lut)
{
int i,val;
int inrange,outrange;
float p;
inrange = arg->right - arg->left +1;
outrange = arg->top - arg->bottom +1;
p = 1/arg->gamma;
for (i = 0; i < arg->left; i++)
lut[i] = 0;
for (; i <= arg->right; i++) {
val = pow((float)(i-arg->left)/inrange,p) * outrange + 0.5;
val += arg->bottom;
if (val < 0) val = 0;
if (val > 255) val = 255;
lut[i] = val;
}
for (; i < 256; i++)
lut[i] = 255;
}
static void*
op_map_init(struct ida_image *src, struct ida_rect *rect,
struct ida_image_info *i, void *parm)
{
struct op_map_parm *args = parm;
struct op_map_lut *lut;
lut = malloc(sizeof(*lut));
build_lut(&args->red,lut->red);
build_lut(&args->green,lut->green);
build_lut(&args->blue,lut->blue);
*i = src->i;
return lut;
}
static void
op_map_work(struct ida_image *src, struct ida_rect *rect,
unsigned char *dst, int line, void *data)
{
struct op_map_lut *lut = data;
unsigned char *scanline;
int i;
scanline = src->data + line * src->i.width * 3;
memcpy(dst,scanline,src->i.width * 3);
if (line < rect->y1 || line >= rect->y2)
return;
dst += 3*rect->x1;
scanline += 3*rect->x1;
for (i = rect->x1; i < rect->x2; i++) {
dst[0] = lut->red[scanline[0]];
dst[1] = lut->green[scanline[1]];
dst[2] = lut->blue[scanline[2]];
scanline += 3;
dst += 3;
}
}
/* ----------------------------------------------------------------------- */
struct ida_op desc_map = {
name: "map",
init: op_map_init,
work: op_map_work,
done: op_free_done,
};
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