/**
* Process value for brightness/contrast filter.
*
* @param double *f - Filter, double of 4
* @param uint32_r value - Value to process
* @return double
**/
static double brcn_filter_process(double *f, uint32_t value)
{
double result;
#define RANGE(i) i[0]
#define SCALE(i) i[1]
#define SLOPE(i) i[2]
#define INTERCEPT(i) i[3]
result = ((SLOPE(f) * SCALE(f)) * value + INTERCEPT(f)) * RANGE(f);
if (result > RANGE(f)) {
result = RANGE(f);
} else if (result < 0.0) {
result = 0.0;
}
#undef RANGE
#undef SCALE
#undef SLOPE
#undef INTERCEPT
return result;
}
/* determine point of detected intersections */
static int intpoint(struct vertex *l, struct vertex *m, float *x, float *y, int cond)
{
struct position ls, le, ms, me, pt1, pt2;
float m1, m2, c1, c2;
if (cond <= 0)
return (0);
ls = l->pos;
le = after(l)->pos;
ms = m->pos;
me = after(m)->pos;
switch (cond) {
case 3: /* a simple intersection */
if (ls.x == le.x) {
*x = ls.x;
*y = me.y + SLOPE(ms, me) * (*x - me.x);
} else if (ms.x == me.x) {
*x = ms.x;
*y = le.y + SLOPE(ls, le) * (*x - le.x);
} else {
m1 = SLOPE(ms, me);
m2 = SLOPE(ls, le);
c1 = ms.y - (m1 * ms.x);
c2 = ls.y - (m2 * ls.x);
*x = (c2 - c1) / (m1 - m2);
*y = ((m1 * c2) - (c1 * m2)) / (m1 - m2);
}
break;
case 2: /* the two lines have a common segment */
if (online(l, m, 0) == -1) { /* ms between ls and le */
pt1 = ms;
pt2 =
(online(m, l, 1) ==
-1) ? ((online(m, l, 0) == -1) ? le : ls) : me;
} else if (online(l, m, 1) == -1) { /* me between ls and le */
pt1 = me;
pt2 =
(online(l, m, 0) ==
-1) ? ((online(m, l, 0) == -1) ? le : ls) : ms;
} else {
/* may be degenerate? */
if (online(m, l, 0) != -1)
return 0;
pt1 = ls;
pt2 = le;
}
*x = (pt1.x + pt2.x) / 2;
*y = (pt1.y + pt2.y) / 2;
break;
case 1: /* a vertex of line m is on line l */
if ((ls.x - le.x) * (ms.y - ls.y) == (ls.y - le.y) * (ms.x - ls.x)) {
*x = ms.x;
*y = ms.y;
} else {
*x = me.x;
*y = me.y;
}
} /* end switch */
return (1);
}
