/* if cross is not NULL, it will be incremented for each ray crossing */
static real
bez_point_distance_and_ray_crosses(const Point *b1,
const Point *b2, const Point *b3,
const Point *b4,
real line_width, const Point *point,
guint *cross)
{
static gboolean calculated_coeff = FALSE;
static real coeff[NBEZ_SEGS+1][4];
int i;
real line_dist = G_MAXFLOAT;
Point prev, pt;
if (!calculated_coeff) {
for (i = 0; i <= NBEZ_SEGS; i++) {
real t1 = ((real)i)/NBEZ_SEGS, t2 = t1*t1, t3 = t1*t2;
real it1 = 1-t1, it2 = it1*it1, it3 = it1*it2;
coeff[i][0] = it3;
coeff[i][1] = 3 * t1 * it2;
coeff[i][2] = 3 * t2 * it1;
coeff[i][3] = t3;
}
}
calculated_coeff = TRUE;
prev.x = coeff[0][0] * b1->x + coeff[0][1] * b2->x +
coeff[0][2] * b3->x + coeff[0][3] * b4->x;
prev.y = coeff[0][0] * b1->y + coeff[0][1] * b2->y +
coeff[0][2] * b3->y + coeff[0][3] * b4->y;
for (i = 1; i <= NBEZ_SEGS; i++) {
real dist;
pt.x = coeff[i][0] * b1->x + coeff[i][1] * b2->x +
coeff[i][2] * b3->x + coeff[i][3] * b4->x;
pt.y = coeff[i][0] * b1->y + coeff[i][1] * b2->y +
coeff[i][2] * b3->y + coeff[i][3] * b4->y;
dist = distance_line_point(&prev, &pt, line_width, point);
line_dist = MIN(line_dist, dist);
if (cross)
*cross += line_crosses_ray(&prev, &pt, point);
prev = pt;
}
return line_dist;
}
real
distance_bez_shape_point(const BezPoint *b, guint npoints,
real line_width, const Point *point)
{
Point last;
guint i;
real line_dist = G_MAXFLOAT;
guint crossings = 0;
g_return_val_if_fail(b[0].type == BEZ_MOVE_TO, -1);
last = b[0].p1;
for (i = 1; i < npoints; i++) {
real dist;
switch (b[i].type) {
case BEZ_MOVE_TO:
/* no complains, there are renderers capable to handle this */
last = b[i].p1;
break;
case BEZ_LINE_TO:
dist = distance_line_point(&last, &b[i].p1, line_width, point);
crossings += line_crosses_ray(&last, &b[i].p1, point);
line_dist = MIN(line_dist, dist);
last = b[i].p1;
break;
case BEZ_CURVE_TO:
dist = bez_point_distance_and_ray_crosses(&last, &b[i].p1, &b[i].p2,
&b[i].p3, line_width, point,
&crossings);
line_dist = MIN(line_dist, dist);
last = b[i].p3;
break;
}
}
/* If there is an odd number of ray crossings, we are inside the polygon.
* Otherwise, return the minium distance from a line segment */
if (crossings % 2 == 1)
return 0.0;
else
return line_dist;
}
real
distance_polygon_point(const Point *poly, guint npoints, real line_width,
const Point *point)
{
guint i, last = npoints - 1;
real line_dist = G_MAXFLOAT;
guint crossings = 0;
/* calculate ray crossings and line distances */
for (i = 0; i < npoints; i++) {
real dist;
crossings += line_crosses_ray(&poly[last], &poly[i], point);
dist = distance_line_point(&poly[last], &poly[i], line_width, point);
line_dist = MIN(line_dist, dist);
last = i;
}
/* If there is an odd number of ray crossings, we are inside the polygon.
* Otherwise, return the minium distance from a line segment */
if (crossings % 2 == 1)
return 0.0;
else
return line_dist;
}
double distance_polygon_point(const Point *poly,
int npoints,
double lineWidth,
const Point *point)
{
int i, last = npoints - 1;
// double line_dist = G_MAXFLOAT;
double line_dist = 1.0;
int crossings = 0;
for (i = 0; i < npoints; i++) {
double dist;
crossings += line_crosses_ray(&poly[last], &poly[i], point);
dist = distance_line_point(&poly[last], &poly[i], lineWidth, point);
line_dist = qMin(line_dist, dist);
last = i;
}
if (crossings % 2 == 1)
return 0.0;
else
return line_dist;
}
