/***************************************************************************
*
*N intersect_polygon_edge
*
*::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* Purpose:
*P
* Count the number of intersections between a plum line from the
* test point and infinity and the vertices of the given edge.
*E
*:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* Parameters:
*A
* x <input> == (float) test point x coordinate.
* y <input> == (float) test point y coordinate.
* edge_rec <input> == (edge_rec_type) given edge.
* intersect_polygon_edge <output> == (int) number of intersection points.
*E
**************************************************************************/
int intersect_polygon_edge( float x, float y, edge_rec_type edge_rec )
{
register rspf_int32 i;
line_segment_type lseg, pseg;
int n;
float xint,yint;
coordinate_type coord1,coord2;
lseg.x1 = x;
lseg.y1 = y;
lseg.x2 = MAXFLOAT/2.0;
lseg.y2 = y;
n = 0;
coord1 = first_edge_coordinate(&edge_rec);
for (i=1;i<edge_rec.npts;i++) {
coord2 = next_edge_coordinate(&edge_rec);
pseg.x1 = coord1.x;
pseg.y1 = coord1.y;
pseg.x2 = coord2.x;
pseg.y2 = coord2.y;
if (intersect(lseg,pseg,&xint,&yint)) {
n++;
}
coord1 = coord2;
}
return n;
}
/**************************************************************************
*
*N distance_to_edge_rec
*
*:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* Purpose:
*P
* This function computes the minimum distance from the given point
* to the given edge record by looking at each segment in the line.
*E
*:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* Parameters:
*A
* x <input> == (float) given point x coordinate.
* y <input> == (float) given point y coordinate
* edge_rec <input> == (edge_rec_type) given edge record.
* dec_degrees <inout> == (int) flag to indicate if coordinates are
* in decimal degrees.
* distance_to_edge_rec <output> == (float) minimum distance to the
* edge record.
*E
*:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* History:
*H
* Barry Michaels, DOS Turbo C 1991
*E
*************************************************************************/
float distance_to_edge_rec( float x, float y, edge_rec_type edge_rec,
int dec_degrees )
{
register long int i;
line_segment_type lseg;
float xint,yint, d, dseg, d1, d2;
coordinate_type coord1, coord2;
d = MAXFLOAT;
coord1 = first_edge_coordinate(&edge_rec);
for (i=1;i<edge_rec.npts;i++) {
coord2 = next_edge_coordinate(&edge_rec);
lseg.x1 = coord1.x;
lseg.y1 = coord1.y;
lseg.x2 = coord2.x;
lseg.y2 = coord2.y;
if (perpendicular_intersection(lseg,x,y,&xint,&yint)) {
if (dec_degrees)
dseg = distance( y, x, yint, xint, 0 );
else
dseg = (float)(sqrt( (xint-x)*(xint-x) + (yint-y)*(yint-y) ));
} else {
if (dec_degrees) {
dseg = (float)min( distance( y, x, lseg.y1, lseg.x1, 0 ),
distance( y, x, lseg.y2, lseg.x2, 0 ) );
} else {
d1 = (float)(sqrt( (lseg.x1-x)*(lseg.x1-x) + (lseg.y1-y)*(lseg.y1-y) ));
d2 = (float)(sqrt( (lseg.x2-x)*(lseg.x2-x) + (lseg.y2-y)*(lseg.y2-y) ));
dseg = (float)min(d1,d2);
}
}
d = (float)min(d,dseg);
coord1 = coord2;
}
return d;
}
/*************************************************************************
*
*N draw_edge_coordinates
*
*::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* Purpose:
*P
* This function draws the coordinates of an edge record.
* It tries its darndest to detect and get rid of projection
* "zingers" - lines that dart across the screen because of
* lines projected onto the map that wrap around behind the
* globe or change hemispheres. The ability to handle these
* projection artifacts is what turns what should be a very
* simple function into a very ugly piece of code.
*E
*::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* Parameters:
*A
* edge_rec <input>==(edge_rec_type *) pointer to an edge record.
* return <output>==(int) 0 if the user escapes, 1 upon successful
* completion.
*E
*::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*
* History:
*H
* Barry Michaels Feb 1992 DOS Turbo C
*E
*************************************************************************/
int draw_edge_coordinates( edge_rec_type *edge_rec )
{
int xscr,yscr, xprev,yprev, x1,y1,x2,y2, mbrx2, wrap;
register ossim_int32 i;
extent_type mbr;
coordinate_type coord;
/* First compute the MBR from the coordinates. */
coord = first_edge_coordinate(edge_rec);
mbr.x1 = coord.x;
mbr.y1 = coord.y;
mbr.x2 = coord.x;
mbr.y2 = coord.y;
for (i=1;i<edge_rec->npts;i++) {
coord = next_edge_coordinate(edge_rec);
if (coord.x < mbr.x1) mbr.x1 = coord.x;
if (coord.y < mbr.y1) mbr.y1 = coord.y;
if (coord.x > mbr.x2) mbr.x2 = coord.x;
if (coord.y > mbr.y2) mbr.y2 = coord.y;
}
screen_bounds(mbr.x1,mbr.y1,mbr.x2,mbr.y2,&x1,&y1,&x2,&y2);
if ( (x1 < 0 && x2 < 0) || (x1 > gpgetmaxx() && x2 > gpgetmaxx()) ||
(y1 < 0 && y2 < 0) || (y1 > gpgetmaxy() && y2 > gpgetmaxy()) )
return 1;
if (x1 > gpgetmaxx() && x2 < 0) return 1;
wrap = 0;
mbrx2 = x2;
if (x2 < x1) {
/* The box wraps around the screen */
/* (or at least wraps off the edge of the screen) */
wrap = gpgetmaxx();
if (x2 < 0) wrap -= x2;
/* Adjust the maximum screen value */
x2 += wrap;
}
coord = first_edge_coordinate(edge_rec);
screenxy(coord.x,coord.y,&xscr,&yscr);
if (wrap && xscr < x1) xscr += wrap;
gpmoveto(xscr,yscr);
xprev = xscr;
yprev = yscr;
for (i=1;i<edge_rec->npts;i++) {
coord = next_edge_coordinate(edge_rec);
screenxy(coord.x,coord.y,&xscr,&yscr);
if (xscr == MAXINT || yscr == MAXINT) {
xprev = xscr;
yprev = yscr;
continue;
}
if (wrap && xscr < x1) xscr += wrap;
if (xscr==xprev && yscr==yprev) continue;
if (xprev == MAXINT || yprev == MAXINT) gpmoveto(xscr,yscr);
hidemousecursor();
gplineto( xscr, yscr );
showmousecursor();
xprev = xscr;
yprev = yscr;
while (kbhit()) {
if (getch()==27) {
return 0;
}
}
}
if (wrap && mbrx2 > 0) {
/* The edge wraps around and is displayed on the other */
/* edge of the screen. */
x2 -= wrap;
coord = first_edge_coordinate(edge_rec);
screenxy(coord.x,coord.y,&xscr,&yscr);
if (xscr > x2) xscr -= wrap;
gpmoveto(xscr,yscr);
xprev = xscr;
yprev = yscr;
for (i=1;i<edge_rec->npts;i++) {
coord = next_edge_coordinate(edge_rec);
screenxy(coord.x,coord.y,&xscr,&yscr);
if (xscr == MAXINT || yscr == MAXINT) {
xprev = xscr;
yprev = yscr;
continue;
}
if (xscr > x2) xscr -= wrap;
if (xscr==xprev && yscr==yprev) continue;
if (xprev == MAXINT || yprev == MAXINT) gpmoveto(xscr,yscr);
hidemousecursor();
gplineto( xscr, yscr );
showmousecursor();
xprev = xscr;
yprev = yscr;
while (kbhit()) {
if (getch()==27) {
return 0;
}
}
}
}
return 1;
}
