static void
plcntr(PLFLT (*f2eval) (PLINT, PLINT, PLPointer),
PLPointer f2eval_data,
PLINT nx, PLINT ny, PLINT kx, PLINT lx,
PLINT ky, PLINT ly, PLFLT flev, PLINT **ipts,
void (*pltr) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer),
PLPointer pltr_data)
{
PLINT kcol, krow, lastindex;
PLFLT distance;
PLFLT save_def, save_scale;
char flabel[30];
plgchr(&save_def, &save_scale);
save_scale = save_scale/save_def;
cont_new_store(flev);
/* format contour label for plptex and define the font height of the labels */
plfloatlabel(flev, flabel);
plschr(0.0, contlabel_size);
/* Clear array for traversed squares */
for (kcol = kx; kcol < lx; kcol++) {
for (krow = ky; krow < ly; krow++) {
ipts[kcol][krow] = 0;
}
}
for (krow = ky; krow < ly; krow++) {
for (kcol = kx; kcol < lx; kcol++) {
if (ipts[kcol][krow] == 0) {
/* Follow and draw a contour */
pldrawcn(f2eval, f2eval_data,
nx, ny, kx, lx, ky, ly, flev, flabel, kcol, krow,
0.0, 0.0, -2, ipts, &distance, &lastindex,
pltr, pltr_data);
if (error)
return;
}
}
}
plschr(save_def, save_scale);
}
static void
pldrawcn(PLFLT (*f2eval) (PLINT, PLINT, PLPointer),
PLPointer f2eval_data,
PLINT nx, PLINT ny, PLINT kx, PLINT lx,
PLINT ky, PLINT ly, PLFLT flev, char *flabel, PLINT kcol, PLINT krow,
PLFLT lastx, PLFLT lasty, PLINT startedge, PLINT **ipts,
PLFLT *distance, PLINT *lastindex,
void (*pltr) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer),
PLPointer pltr_data)
{
PLFLT f[4];
PLFLT px[4], py[4], locx[4], locy[4];
PLINT iedge[4];
PLINT i, j, k, num, first, inext, kcolnext, krownext;
(*pltr) (kcol,krow+1,&px[0],&py[0],pltr_data);
(*pltr) (kcol,krow,&px[1],&py[1],pltr_data);
(*pltr) (kcol+1,krow,&px[2],&py[2],pltr_data);
(*pltr) (kcol+1,krow+1,&px[3],&py[3],pltr_data);
f[0] = f2eval(kcol, krow+1, f2eval_data)-flev;
f[1] = f2eval(kcol, krow, f2eval_data)-flev;
f[2] = f2eval(kcol+1, krow, f2eval_data)-flev;
f[3] = f2eval(kcol+1, krow+1, f2eval_data)-flev;
for (i=0,j=1;i<4;i++,j = (j+1)%4) {
iedge[i] = (f[i]*f[j]>0.0)?-1:((f[i]*f[j] < 0.0)?1:0);
}
/* Mark this square as done */
ipts[kcol][krow] = 1;
/* Check if no contour has been crossed i.e. iedge[i] = -1 */
if ((iedge[0] == -1) && (iedge[1] == -1) && (iedge[2] == -1)
&& (iedge[3] == -1)) return;
/* Check if this is a completely flat square - in which case
ignore it */
if ( (f[0] == 0.0) && (f[1] == 0.0) && (f[2] == 0.0) &&
(f[3] == 0.0) ) return;
/* Calculate intersection points */
num = 0;
if (startedge < 0) {
first = 1;
}
else {
locx[num] = lastx;
locy[num] = lasty;
num++;
first = 0;
}
for (k=0, i = (startedge<0?0:startedge);k<4;k++,i=(i+1)%4) {
if (i == startedge) continue;
/* If the contour is an edge check it hasn't already been done */
if (f[i] == 0.0 && f[(i+1)%4] == 0.0) {
kcolnext = kcol;
krownext = krow;
if (i == 0) kcolnext--;
if (i == 1) krownext--;
if (i == 2) kcolnext++;
if (i == 3) krownext++;
if ((kcolnext < kx) || (kcolnext >= lx) ||
(krownext < ky) || (krownext >= ly) ||
(ipts[kcolnext][krownext] == 1)) continue;
}
if ((iedge[i] == 1) || (f[i] == 0.0)) {
j = (i+1)%4;
if (f[i] != 0.0) {
locx[num] = (px[i]*fabs(f[j])+px[j]*fabs(f[i]))/fabs(f[j]-f[i]);
locy[num] = (py[i]*fabs(f[j])+py[j]*fabs(f[i]))/fabs(f[j]-f[i]);
}
else {
locx[num] = px[i];
locy[num] = py[i];
}
/* If this is the start of the contour then move to the point */
if (first == 1) {
cont_mv_store(locx[num],locy[num]);
first = 0;
*distance = 0;
*lastindex = 0;
}
else {
/* Link to the next point on the contour */
if (contlabel_active)
pl_drawcontlabel(locx[num], locy[num], flabel, distance, lastindex);
else
cont_xy_store(locx[num],locy[num]);
/* Need to follow contour into next grid box */
/* Easy case where contour does not pass through corner */
if (f[i] != 0.0) {
kcolnext = kcol;
krownext = krow;
inext = (i+2)%4;
if (i == 0) kcolnext--;
if (i == 1) krownext--;
if (i == 2) kcolnext++;
if (i == 3) krownext++;
if ((kcolnext >= kx) && (kcolnext < lx) &&
(krownext >= ky) && (krownext < ly) &&
(ipts[kcolnext][krownext] == 0)) {
pldrawcn(f2eval, f2eval_data,
nx, ny, kx, lx, ky, ly, flev, flabel,
kcolnext, krownext,
locx[num], locy[num], inext, ipts,
distance, lastindex,
pltr, pltr_data);
}
}
/* Hard case where contour passes through corner */
/* This is still not perfect - it may lose the contour
* which won't upset the contour itself (we can find it
* again later) but might upset the labelling */
else {
kcolnext = kcol;
krownext = krow;
inext = (i+2)%4;
if (i == 0) {kcolnext--; krownext++;}
if (i == 1) {krownext--; kcolnext--;}
if (i == 2) {kcolnext++; krownext--;}
if (i == 3) {krownext++; kcolnext++;}
if ((kcolnext >= kx) && (kcolnext < lx) &&
(krownext >= ky) && (krownext < ly) &&
(ipts[kcolnext][krownext] == 0)) {
pldrawcn(f2eval, f2eval_data,
nx, ny, kx, lx, ky, ly, flev, flabel,
kcolnext, krownext,
locx[num], locy[num], inext, ipts,
distance, lastindex,
pltr, pltr_data);
}
}
if (first == 1) {
/* Move back to first point */
cont_mv_store(locx[num],locy[num]);
first = 0;
*distance = 0;
*lastindex = 0;
first = 0;
}
else {
first = 1;
}
num++;
}
}
}
}
static void
plcntr(PLFLT (*f2eval) (PLINT, PLINT, PLPointer),
PLPointer f2eval_data,
PLINT nx, PLINT ny, PLINT kx, PLINT lx,
PLINT ky, PLINT ly, PLFLT flev, PLINT *iscan,
PLINT *ixstor, PLINT *iystor, PLINT nstor,
void (*pltr) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer),
PLPointer pltr_data)
{
PLINT kcol, krow, kstor, kscan, l, ixt, iyt, jstor, next;
char flabel[30];
cont_new_store(flev);
/* format contour label for plptex and define the font height of the labels */
plfloatlabel(flev, flabel);
plschr(0.0, contlabel_size);
/* Initialize memory pointers */
kstor = 0;
kscan = 0;
for (krow = ky; krow <= ly; krow++) {
for (kcol = kx + 1; kcol <= lx; kcol++) {
/* Follow and draw a contour */
pldrawcn(f2eval, f2eval_data,
nx, ny, kx, lx, ky, ly, flev, flabel, kcol, krow,
&kscan, &kstor, iscan, ixstor, iystor, nstor,
pltr, pltr_data);
if (error)
return;
}
/* Search of row complete */
/* Set up memory of next row in iscan and edit ixstor and iystor */
if (krow < ny-1) {
jstor = 0;
kscan = 0;
next = krow + 1;
for (l = 1; l <= kstor; l++) {
ixt = ixstor[l - 1];
iyt = iystor[l - 1];
/* Memory of next row into iscan */
if (iyt == next) {
kscan = kscan + 1;
iscan[kscan - 1] = ixt;
}
/* Retain memory of rows to come, and forget rest */
else if (iyt > next) {
jstor = jstor + 1;
ixstor[jstor - 1] = ixt;
iystor[jstor - 1] = iyt;
}
}
kstor = jstor;
}
}
plschr(0.0, 1.0);
}
