IGL_INLINE void igl::circulation(
const int e,
const bool ccw,
const Eigen::MatrixXi & F,
const Eigen::MatrixXi & E,
const Eigen::VectorXi & EMAP,
const Eigen::MatrixXi & EF,
const Eigen::MatrixXi & EI,
Eigen::VectorXi & vN)
{
std::vector<int> N = circulation(e,ccw,F,E,EMAP,EF,EI);
igl::list_to_matrix(N,vN);
}
void
plP_plfclp(PLINT *x, PLINT *y, PLINT npts,
PLINT xmin, PLINT xmax, PLINT ymin, PLINT ymax,
void (*draw) (short *, short *, PLINT))
{
PLINT i, xx1, xx2, yy1, yy2;
int iclp = 0, iout = 2;
short _xclp[2*PL_MAXPOLY+2], _yclp[2*PL_MAXPOLY+2];
short *xclp, *yclp;
int drawable;
int crossed_xmin1 = 0, crossed_xmax1 = 0;
int crossed_ymin1 = 0, crossed_ymax1 = 0;
int crossed_xmin2 = 0, crossed_xmax2 = 0;
int crossed_ymin2 = 0, crossed_ymax2 = 0;
int crossed_up = 0, crossed_down = 0;
int crossed_left = 0, crossed_right = 0;
int inside_lb ;
int inside_lu ;
int inside_rb ;
int inside_ru ;
/* Must have at least 3 points and draw() specified */
if (npts < 3 || !draw) return;
if ( npts < PL_MAXPOLY ) {
xclp = _xclp;
yclp = _yclp;
} else {
xclp = (short *) malloc( (2*npts+2)*sizeof(short) ) ;
yclp = (short *) malloc( (2*npts+2)*sizeof(short) ) ;
}
inside_lb = pointinpolygon(npts,x,y,xmin,ymin) ;
inside_lu = pointinpolygon(npts,x,y,xmin,ymax) ;
inside_rb = pointinpolygon(npts,x,y,xmax,ymin) ;
inside_ru = pointinpolygon(npts,x,y,xmax,ymax) ;
for (i = 0; i < npts - 1; i++) {
xx1 = x[i]; xx2 = x[i+1];
yy1 = y[i]; yy2 = y[i+1];
drawable = (INSIDE(xx1, yy1) && INSIDE(xx2, yy2));
if ( ! drawable)
drawable = ! clipline(&xx1, &yy1, &xx2, &yy2,
xmin, xmax, ymin, ymax);
if (drawable) {
/* Boundary crossing condition -- coming in. */
crossed_xmin2 = (xx1 == xmin); crossed_xmax2 = (xx1 == xmax);
crossed_ymin2 = (yy1 == ymin); crossed_ymax2 = (yy1 == ymax);
crossed_left = (crossed_left || crossed_xmin2);
crossed_right = (crossed_right || crossed_xmax2);
crossed_down = (crossed_down || crossed_ymin2);
crossed_up = (crossed_up || crossed_ymax2);
iout = iclp+2;
/* If the first segment, just add it. */
if (iclp == 0) {
xclp[iclp] = xx1; yclp[iclp] = yy1; iclp++;
xclp[iclp] = xx2; yclp[iclp] = yy2; iclp++;
}
/* Not first point. If first point of this segment matches up to the
previous point, just add it. */
else if (xx1 == xclp[iclp-1] && yy1 == yclp[iclp-1]) {
xclp[iclp] = xx2; yclp[iclp] = yy2; iclp++;
}
/* Otherwise, we need to add both points, to connect the points in the
* polygon along the clip boundary. If we encircled a corner, we have
* to add that first.
*/
else {
/* Treat the case where we encircled two corners:
Construct a polygon out of the subset of vertices
Note that the direction is important too when adding
the extra points */
xclp[iclp+1] = xx2; yclp[iclp+1] = yy2;
xclp[iclp+2] = xx1; yclp[iclp+2] = yy1;
iout = iout - iclp + 1;
/* Upper two */
if ( ((crossed_xmin1 && crossed_xmax2) ||
(crossed_xmin2 && crossed_xmax1)) &&
inside_lu )
{
if ( crossed_xmin1 )
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
} else {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
}
/* Lower two */
else if ( ((crossed_xmin1 && crossed_xmax2) ||
(crossed_xmin2 && crossed_xmax1)) &&
inside_lb )
{
if ( crossed_xmin1 )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
} else {
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
/* Left two */
else if ( ((crossed_ymin1 && crossed_ymax2) ||
(crossed_ymin2 && crossed_ymax1)) &&
inside_lb )
{
if ( crossed_ymin1 )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
} else {
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
/* Right two */
else if ( ((crossed_ymin1 && crossed_ymax2) ||
(crossed_ymin2 && crossed_ymax1)) &&
inside_rb )
{
if ( crossed_ymin1 )
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
} else {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
}
/* Now the case where we encircled one corner */
/* Lower left */
else if ( (crossed_xmin1 && crossed_ymin2) ||
(crossed_ymin1 && crossed_xmin2) )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
/* Lower right */
else if ( (crossed_xmax1 && crossed_ymin2) ||
(crossed_ymin1 && crossed_xmax2) )
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* Upper left */
else if ( (crossed_xmin1 && crossed_ymax2) ||
(crossed_ymax1 && crossed_xmin2) )
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* Upper right */
else if ( (crossed_xmax1 && crossed_ymax2) ||
(crossed_ymax1 && crossed_xmax2) )
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* Now add current segment. */
xclp[iclp] = xx1; yclp[iclp] = yy1; iclp++;
xclp[iclp] = xx2; yclp[iclp] = yy2; iclp++;
}
/* Boundary crossing condition -- going out. */
crossed_xmin1 = (xx2 == xmin); crossed_xmax1 = (xx2 == xmax);
crossed_ymin1 = (yy2 == ymin); crossed_ymax1 = (yy2 == ymax);
}
}
/* Limit case - all vertices are outside of bounding box. So just fill entire
box, *if* the bounding box is completely encircled.
*/
if (iclp == 0) {
PLINT xmin1, xmax1, ymin1, ymax1;
xmin1 = xmax1 = x[0];
ymin1 = ymax1 = y[0];
for (i = 1; i < npts; i++) {
if (x[i] < xmin1) xmin1 = x[i];
if (x[i] > xmax1) xmax1 = x[i];
if (y[i] < ymin1) ymin1 = y[i];
if (y[i] > ymax1) ymax1 = y[i];
}
if (xmin1 <= xmin && xmax1 >= xmax && ymin1 <= ymin && ymax1 >= ymax ) {
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
(*draw)(xclp, yclp, iclp);
if ( xclp != _xclp ) {
free( xclp );
free( yclp );
}
return;
}
}
/* Now handle cases where fill polygon intersects two sides of the box */
if (iclp >= 2) {
int debug=0;
int dir = circulation(x, y, npts);
if (debug) {
if ( (xclp[0] == xmin && xclp[iclp-1] == xmax) ||
(xclp[0] == xmax && xclp[iclp-1] == xmin) ||
(yclp[0] == ymin && yclp[iclp-1] == ymax) ||
(yclp[0] == ymax && yclp[iclp-1] == ymin) ||
(xclp[0] == xmin && yclp[iclp-1] == ymin) ||
(yclp[0] == ymin && xclp[iclp-1] == xmin) ||
(xclp[0] == xmax && yclp[iclp-1] == ymin) ||
(yclp[0] == ymin && xclp[iclp-1] == xmax) ||
(xclp[0] == xmax && yclp[iclp-1] == ymax) ||
(yclp[0] == ymax && xclp[iclp-1] == xmax) ||
(xclp[0] == xmin && yclp[iclp-1] == ymax) ||
(yclp[0] == ymax && xclp[iclp-1] == xmin) ) {
printf("dir=%d, clipped points:\n", dir);
for (i=0; i < iclp; i++)
printf(" x[%d]=%d y[%d]=%d", i, xclp[i], i, yclp[i]);
printf("\n");
printf("pre-clipped points:\n");
for (i=0; i < npts; i++)
printf(" x[%d]=%d y[%d]=%d", i, x[i], i, y[i]);
printf("\n");
}
}
/* The cases where the fill region is divided 2/2 */
/* Divided horizontally */
if (xclp[0] == xmin && xclp[iclp-1] == xmax)
{
if (dir > 0) {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
else {
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
else if (xclp[0] == xmax && xclp[iclp-1] == xmin)
{
if (dir > 0) {
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
else {
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
}
/* Divided vertically */
else if (yclp[0] == ymin && yclp[iclp-1] == ymax)
{
if (dir > 0) {
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
else {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
}
else if (yclp[0] == ymax && yclp[iclp-1] == ymin)
{
if (dir > 0) {
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
else {
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
}
/* The cases where the fill region is divided 3/1 --
LL LR UR UL
+-----+ +-----+ +-----+ +-----+
| | | | | \| |/ |
| | | | | | | |
|\ | | /| | | | |
+-----+ +-----+ +-----+ +-----+
Note when we go the long way around, if the direction is reversed the
three vertices must be visited in the opposite order.
*/
/* LL, short way around */
else if ((xclp[0] == xmin && yclp[iclp-1] == ymin && dir < 0) ||
(yclp[0] == ymin && xclp[iclp-1] == xmin && dir > 0) )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
/* LL, long way around, counterclockwise */
else if ((xclp[0] == xmin && yclp[iclp-1] == ymin && dir > 0))
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* LL, long way around, clockwise */
else if ((yclp[0] == ymin && xclp[iclp-1] == xmin && dir < 0))
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* LR, short way around */
else if ((xclp[0] == xmax && yclp[iclp-1] == ymin && dir > 0) ||
(yclp[0] == ymin && xclp[iclp-1] == xmax && dir < 0) )
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* LR, long way around, counterclockwise */
else if (yclp[0] == ymin && xclp[iclp-1] == xmax && dir > 0)
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
/* LR, long way around, clockwise */
else if (xclp[0] == xmax && yclp[iclp-1] == ymin && dir < 0)
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* UR, short way around */
else if ((xclp[0] == xmax && yclp[iclp-1] == ymax && dir < 0) ||
(yclp[0] == ymax && xclp[iclp-1] == xmax && dir > 0) )
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* UR, long way around, counterclockwise */
else if (xclp[0] == xmax && yclp[iclp-1] == ymax && dir > 0)
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* UR, long way around, clockwise */
else if (yclp[0] == ymax && xclp[iclp-1] == xmax && dir < 0)
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* UL, short way around */
else if ((xclp[0] == xmin && yclp[iclp-1] == ymax && dir > 0) ||
(yclp[0] == ymax && xclp[iclp-1] == xmin && dir < 0) )
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* UL, long way around, counterclockwise */
else if (yclp[0] == ymax && xclp[iclp-1] == xmin && dir > 0)
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* UL, long way around, clockwise */
else if (xclp[0] == xmin && yclp[iclp-1] == ymax && dir < 0)
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
/* Check for the case that only one side has been crossed
(AM) Just checking a single point turns out not to be
enough, apparently the crossed_*1 and crossed_*2 variables
are not quite what I expected.
*/
if ( crossed_left+crossed_right+crossed_down+crossed_up == 1 &&
inside_lb+inside_rb+inside_lu+inside_ru == 4 ) {
int dir = circulation(x, y, npts);
PLINT xlim[4], ylim[4];
int insert;
int incr;
xlim[0] = xmin ; ylim[0] = ymin ;
xlim[1] = xmax ; ylim[1] = ymin ;
xlim[2] = xmax ; ylim[2] = ymax ;
xlim[3] = xmin ; ylim[3] = ymax ;
if ( dir > 0 ) {
incr = 1;
insert = 0*crossed_left + 1*crossed_down + 2*crossed_right +
3*crossed_up ;
} else {
incr = -1;
insert = 3*crossed_left + 2*crossed_up + 1*crossed_right +
0*crossed_down ;
}
for ( i=0; i < 4; i ++ ) {
xclp[iclp] = xlim[insert] ;
yclp[iclp] = ylim[insert] ;
iclp ++ ;
insert += incr ;
if ( insert > 3 ) insert = 0 ;
if ( insert < 0 ) insert = 3 ;
}
}
/* Draw the sucker */
if (iclp >= 3)
(*draw)(xclp, yclp, iclp);
if ( xclp != _xclp ) {
free( xclp );
free( yclp );
}
}
void
plP_plfclp(PLINT *x, PLINT *y, PLINT npts,
PLINT xmin, PLINT xmax, PLINT ymin, PLINT ymax,
void (*draw) (short *, short *, PLINT))
{
PLINT i, x1, x2, y1, y2;
int iclp = 0, iout = 2;
short xclp[2*PL_MAXPOLY+2], yclp[2*PL_MAXPOLY+2];
int drawable;
int crossed_xmin1 = 0, crossed_xmax1 = 0;
int crossed_ymin1 = 0, crossed_ymax1 = 0;
int crossed_xmin2 = 0, crossed_xmax2 = 0;
int crossed_ymin2 = 0, crossed_ymax2 = 0;
/* Must have at least 3 points and draw() specified */
if (npts < 3 || !draw) return;
for (i = 0; i < npts - 1; i++) {
x1 = x[i]; x2 = x[i+1];
y1 = y[i]; y2 = y[i+1];
drawable = (INSIDE(x1, y1) && INSIDE(x2, y2));
if ( ! drawable)
drawable = ! clipline(&x1, &y1, &x2, &y2, xmin, xmax, ymin, ymax);
if (!drawable) {
/* Store the edges outside the viewport */
xclp[iout] = x2;
yclp[iout] = y2;
iout ++;
} else {
/* Boundary crossing condition -- coming in. */
crossed_xmin2 = (x1 == xmin); crossed_xmax2 = (x1 == xmax);
crossed_ymin2 = (y1 == ymin); crossed_ymax2 = (y1 == ymax);
iout = iclp+2;
/* If the first segment, just add it. */
if (iclp == 0) {
xclp[iclp] = x1; yclp[iclp] = y1; iclp++;
xclp[iclp] = x2; yclp[iclp] = y2; iclp++;
}
/* Not first point. If first point of this segment matches up to the
previous point, just add it. */
else if (x1 == xclp[iclp-1] && y1 == yclp[iclp-1]) {
xclp[iclp] = x2; yclp[iclp] = y2; iclp++;
}
/* Otherwise, we need to add both points, to connect the points in the
* polygon along the clip boundary. If we encircled a corner, we have
* to add that first.
*/
else {
/* Treat the case where we encircled two corners:
Construct a polygon out of the subset of vertices
Note that the direction is important too when adding
the extra points */
xclp[iclp+1] = x2; yclp[iclp+1] = y2;
xclp[iclp+2] = x1; yclp[iclp+2] = y1;
iout = iout - iclp;
/* Upper two */
if ( ((crossed_xmin1 && crossed_xmax2) ||
(crossed_xmin2 && crossed_xmax1)) &&
pointinpolygon(iout,&xclp[iclp+1],&yclp[iclp+1],xmin,ymax) )
{
if ( crossed_xmin1 )
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
} else {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
}
/* Lower two */
else if ( ((crossed_xmin1 && crossed_xmax2) ||
(crossed_xmin2 && crossed_xmax1)) &&
pointinpolygon(iout,&xclp[iclp+1],&yclp[iclp+1],xmin,ymin) )
{
if ( crossed_xmin1 )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
} else {
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
/* Left two */
else if ( ((crossed_ymin1 && crossed_ymax2) ||
(crossed_ymin2 && crossed_ymax1)) &&
pointinpolygon(iout,&xclp[iclp+1],&yclp[iclp+1],xmin,ymin) )
{
if ( crossed_ymin1 )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
} else {
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
/* Right two */
else if ( ((crossed_ymin1 && crossed_ymax2) ||
(crossed_ymin2 && crossed_ymax1)) &&
pointinpolygon(iout,&xclp[iclp+1],&yclp[iclp+1],xmax,ymin) )
{
if ( crossed_ymin1 )
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
} else {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
}
/* Now the case where we encircled one corner */
/* Lower left */
else if ( (crossed_xmin1 && crossed_ymin2) ||
(crossed_ymin1 && crossed_xmin2) )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
/* Lower right */
else if ( (crossed_xmax1 && crossed_ymin2) ||
(crossed_ymin1 && crossed_xmax2) )
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* Upper left */
else if ( (crossed_xmin1 && crossed_ymax2) ||
(crossed_ymax1 && crossed_xmin2) )
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* Upper right */
else if ( (crossed_xmax1 && crossed_ymax2) ||
(crossed_ymax1 && crossed_xmax2) )
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* Now add current segment. */
xclp[iclp] = x1; yclp[iclp] = y1; iclp++;
xclp[iclp] = x2; yclp[iclp] = y2; iclp++;
}
/* Boundary crossing condition -- going out. */
crossed_xmin1 = (x2 == xmin); crossed_xmax1 = (x2 == xmax);
crossed_ymin1 = (y2 == ymin); crossed_ymax1 = (y2 == ymax);
}
}
/* Limit case - all vertices are outside of bounding box. So just fill entire
box, *if* the bounding box is completely encircled.
*/
if (iclp == 0) {
PLINT xmin1, xmax1, ymin1, ymax1;
xmin1 = xmax1 = x[0];
ymin1 = ymax1 = y[0];
for (i = 1; i < npts; i++) {
if (x[i] < xmin1) xmin1 = x[i];
if (x[i] > xmax1) xmax1 = x[i];
if (y[i] < ymin1) ymin1 = y[i];
if (y[i] > ymax1) ymax1 = y[i];
}
if (xmin1 <= xmin && xmax1 >= xmax && ymin1 <= ymin && ymax1 >= ymax ) {
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
(*draw)(xclp, yclp, iclp);
return;
}
}
/* Now handle cases where fill polygon intersects two sides of the box */
if (iclp >= 2) {
int debug=0;
int dir = circulation(x, y, npts);
if (debug) {
if ( (xclp[0] == xmin && xclp[iclp-1] == xmax) ||
(xclp[0] == xmax && xclp[iclp-1] == xmin) ||
(yclp[0] == ymin && yclp[iclp-1] == ymax) ||
(yclp[0] == ymax && yclp[iclp-1] == ymin) ||
(xclp[0] == xmin && yclp[iclp-1] == ymin) ||
(yclp[0] == ymin && xclp[iclp-1] == xmin) ||
(xclp[0] == xmax && yclp[iclp-1] == ymin) ||
(yclp[0] == ymin && xclp[iclp-1] == xmax) ||
(xclp[0] == xmax && yclp[iclp-1] == ymax) ||
(yclp[0] == ymax && xclp[iclp-1] == xmax) ||
(xclp[0] == xmin && yclp[iclp-1] == ymax) ||
(yclp[0] == ymax && xclp[iclp-1] == xmin) ) {
printf("dir=%d, clipped points:\n", dir);
for (i=0; i < iclp; i++)
printf(" x[%d]=%d y[%d]=%d", i, xclp[i], i, yclp[i]);
printf("\n");
printf("pre-clipped points:\n");
for (i=0; i < npts; i++)
printf(" x[%d]=%d y[%d]=%d", i, x[i], i, y[i]);
printf("\n");
}
}
/* The cases where the fill region is divided 2/2 */
/* Divided horizontally */
if (xclp[0] == xmin && xclp[iclp-1] == xmax)
{
if (dir > 0) {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
else {
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
else if (xclp[0] == xmax && xclp[iclp-1] == xmin)
{
if (dir > 0) {
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
else {
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
}
/* Divided vertically */
else if (yclp[0] == ymin && yclp[iclp-1] == ymax)
{
if (dir > 0) {
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
else {
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
}
else if (yclp[0] == ymax && yclp[iclp-1] == ymin)
{
if (dir > 0) {
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
else {
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
}
/* The cases where the fill region is divided 3/1 --
LL LR UR UL
+-----+ +-----+ +-----+ +-----+
| | | | | \| |/ |
| | | | | | | |
|\ | | /| | | | |
+-----+ +-----+ +-----+ +-----+
Note when we go the long way around, if the direction is reversed the
three vertices must be visited in the opposite order.
*/
/* LL, short way around */
else if ((xclp[0] == xmin && yclp[iclp-1] == ymin && dir < 0) ||
(yclp[0] == ymin && xclp[iclp-1] == xmin && dir > 0) )
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
/* LL, long way around, counterclockwise */
else if ((xclp[0] == xmin && yclp[iclp-1] == ymin && dir > 0))
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* LL, long way around, clockwise */
else if ((yclp[0] == ymin && xclp[iclp-1] == xmin && dir < 0))
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* LR, short way around */
else if ((xclp[0] == xmax && yclp[iclp-1] == ymin && dir > 0) ||
(yclp[0] == ymin && xclp[iclp-1] == xmax && dir < 0) )
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* LR, long way around, counterclockwise */
else if (yclp[0] == ymin && xclp[iclp-1] == xmax && dir > 0)
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
/* LR, long way around, clockwise */
else if (xclp[0] == xmax && yclp[iclp-1] == ymin && dir < 0)
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* UR, short way around */
else if ((xclp[0] == xmax && yclp[iclp-1] == ymax && dir < 0) ||
(yclp[0] == ymax && xclp[iclp-1] == xmax && dir > 0) )
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* UR, long way around, counterclockwise */
else if (xclp[0] == xmax && yclp[iclp-1] == ymax && dir > 0)
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
}
/* UR, long way around, clockwise */
else if (yclp[0] == ymax && xclp[iclp-1] == xmax && dir < 0)
{
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* UL, short way around */
else if ((xclp[0] == xmin && yclp[iclp-1] == ymax && dir > 0) ||
(yclp[0] == ymax && xclp[iclp-1] == xmin && dir < 0) )
{
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
}
/* UL, long way around, counterclockwise */
else if (yclp[0] == ymax && xclp[iclp-1] == xmin && dir > 0)
{
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymin; iclp++;
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
}
/* UL, long way around, clockwise */
else if (xclp[0] == xmin && yclp[iclp-1] == ymax && dir < 0)
{
xclp[iclp] = xmax; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymax; iclp++;
xclp[iclp] = xmin; yclp[iclp] = ymin; iclp++;
}
}
/* Draw the sucker */
if (iclp >= 3)
(*draw)(xclp, yclp, iclp);
}