void strmar (gadouble xx1, gadouble yy1, gadouble xx2, gadouble yy2) {
gadouble dir;
dir = atan2(yy2-yy1,xx2-xx1);
gxplot (xx2,yy2,3);
gxplot (xx2+0.05*cos(dir+a150),yy2+0.05*sin(dir+a150),2);
gxplot (xx2,yy2,3);
gxplot (xx2+0.05*cos(dir-a150),yy2+0.05*sin(dir-a150),2);
gxplot (xx2,yy2,3);
}
void chksid (void) {
gaint *f1,*f4;
gaint i,j;
gadouble x,y;
f1 = flgh;
f4 = flgv;
for (j=1; j<=jmax; j++) {
for (i=1; i<=imax; i++) {
if (i<imax) {
if (*f1==1) gxcolr(1);
else if (*f1==7) gxcolr(3);
else if (*f1==8) gxcolr(8);
else if (*f1==9) gxcolr(4);
else if (*f1==0) gxcolr(15);
else gxcolr(2);
gxconv((gadouble)i,(gadouble)j,&x,&y,3);
gxplot(x,y,3);
gxconv((gadouble)(i+1),(gadouble)j,&x,&y,3);
gxplot(x,y,2);
}
if (j<jmax) {
if (*f4==1) gxcolr(1);
else if (*f4==7) gxcolr(3);
else if (*f4==8) gxcolr(8);
else if (*f4==9) gxcolr(4);
else if (*f4==0) gxcolr(15);
else gxcolr(2);
gxconv((gadouble)i,(gadouble)j,&x,&y,3);
gxplot(x,y,3);
gxconv((gadouble)i,(gadouble)(j+1),&x,&y,3);
gxplot(x,y,2);
}
f1++; f4++;
}
}
gxfrme (0);
}
void gxstrm (gadouble *u, gadouble *v, gadouble *c, gaint is, gaint js,
char *umask, char *vmask, char *cmask, gaint flag, gadouble *shdlvs,
gaint *shdcls, gaint shdcnt, gaint den) {
gadouble x,y,xx,yy;
gadouble *up, *vp, *cp, cv1,cv2,cv;
gadouble uv1,uv2,uv,vv1,vv2,vv,auv,avv,xsav,ysav,xold=0.0,yold=0.0;
gadouble fact,rscl,xxsv,yysv;
gaint i,ii,jj,ii1,ij1,i2,j2,ipt,acnt,icol,scol,dis;
gaint *it,siz,iacc,iisav,iscl,imn,imx,jmn,jmx,iz,jz,iss,jss,bflg;
char *upmask,*vpmask,*cpmask;
scol = -9;
icol = 1;
/* Figure out the interval for the flag grid */
i = is;
if (js>i) i = js;
iscl = 200/i;
iscl = iscl + den - 5;
if (iscl<1) iscl=1;
if (iscl>10) iscl=10;
fact = 0.5/((gadouble)iscl);
rscl = (gadouble)iscl;
/* Allocate memory for the flag grid */
iss = is*iscl;
jss = js*iscl;
siz = iss*jss;
it = (gaint *)malloc(sizeof(gaint) * siz);
if (it==NULL) {
printf ("Cannot allocate memory for streamline function\n");
return;
}
for (i=0; i<siz; i++) *(it+i) = 0;
/* Loop through flag grid to look for start of streamlines.
To start requires no streams drawn within surrounding
flag boxes. */
i2 = 0;
j2 = 0;
for (i=0; i<siz; i++) {
dis = 2;
if (den<5) dis = 3;
if (den>5) dis = 1;
imn = i2-dis;
imx = i2+dis+1;
jmn = j2-dis;
jmx = j2+dis+1;
if (imn<0) imn = 0;
if (imx>iss) imx = iss;
if (jmn<0) jmn = 0;
if (jmx>jss) jmx = jss;
iacc = 0;
for (jz=jmn; jz<jmx; jz++) {
ipt = jz*iss+imn;
for (iz=imn; iz<imx; iz++) {
iacc = iacc + *(it+ipt);
ipt++;
}
}
if (iacc==0) {
x = ((gadouble)i2)/rscl;
y = ((gadouble)j2)/rscl;
xsav = x;
ysav = y;
gxconv (x+1.0,y+1.0,&xx,&yy,3);
gxplot (xx,yy,3);
xxsv = xx;
yysv = yy;
iisav = -999;
iacc = 0;
acnt = 0;
bflg = 0;
while (x>=0.0 && x<(gadouble)(is-1) && y>=0.0 && y<(gadouble)(js-1)) {
ii = (gaint)x;
jj = (gaint)y;
xx = x - (gadouble)ii;
yy = y - (gadouble)jj;
up = u + jj*is+ii;
upmask = umask + jj*is+ii;
vp = v + jj*is+ii;
vpmask = vmask + jj*is+ii;
if (*upmask==0 ||
*(upmask+1)==0 ||
*(upmask+is)==0 ||
*(upmask+is+1)==0) break;
if (*vpmask==0 ||
*(vpmask+1)==0 ||
*(vpmask+is)==0 ||
*(vpmask+is+1)==0) break;
if (flag) {
cp = c + jj*is+ii;
cpmask = cmask + jj*is+ii;
if (*cpmask==0 ||
*(cpmask+1)==0 ||
*(cpmask+is)==0 ||
*(cpmask+is+1)==0) icol = 15;
else {
cv1 = *cp + (*(cp+1)-*cp)*xx;
cv2 = *(cp+is) + (*(cp+is+1)-*(cp+is))*xx;
cv = cv1 + (cv2-cv1)*yy;
icol = gxshdc(shdlvs,shdcls,shdcnt,cv);
}
if (icol!=scol && icol>-1) gxcolr(icol);
scol = icol;
}
uv1 = *up + (*(up+1)-*up)*xx;
uv2 = *(up+is) + (*(up+is+1)-*(up+is))*xx;
uv = uv1 + (uv2-uv1)*yy;
vv1 = *vp + (*(vp+1)-*vp)*xx;
vv2 = *(vp+is) + (*(vp+is+1)-*(vp+is))*xx;
vv = vv1 + (vv2-vv1)*yy;
auv = fabs(uv);
avv=fabs(vv);
if (auv<0.1 && avv<0.1) break;
if (auv>avv) {
vv = vv*fact/auv;
uv = uv*fact/auv;
} else {
uv = uv*fact/avv;
vv = vv*fact/avv;
}
x = x + uv;
y = y + vv;
ii1 = (gaint)(x*rscl);
ij1 = (gaint)(y*rscl);
ii1 = ij1*iss + ii1;
if (ii1<0 || ii1>=siz) break;
if (*(it+ii1)==1) break;
if (ii1!=iisav && iisav>-1) *(it+iisav) = 1;
if (ii1==iisav) iacc++;
else iacc = 0;
if (iacc>10) break;
iisav = ii1;
gxconv (x+1.0,y+1.0,&xx,&yy,3);
if (icol>-1) {
if (bflg) {
gxplot(xold,yold,3);
bflg=0;
}
gxplot (xx,yy,2);
} else bflg = 1;
xold = xx;
yold = yy;
acnt++;
if (acnt>20) {
if (icol>-1) strmar (xxsv,yysv,xx,yy);
acnt = 0;
}
xxsv = xx;
yysv = yy;
}
bflg = 0;
x = xsav;
y = ysav;
gxconv (x+1.0,y+1.0,&xx,&yy,3);
gxplot (xx,yy,3);
xxsv = xx;
yysv = yy;
iisav = -999;
iacc = 0;
acnt = 19;
while (x>=0.0 && x<(gadouble)(is-1) && y>=0.0 && y<(gadouble)(js-1)) {
ii = (gaint)x;
jj = (gaint)y;
xx = x - (gadouble)ii;
yy = y - (gadouble)jj;
up = u + jj*is+ii;
upmask = umask + jj*is+ii;
vp = v + jj*is+ii;
vpmask = vmask + jj*is+ii;
if (*upmask==0 ||
*(upmask+1)==0 ||
*(upmask+is)==0 ||
*(upmask+is+1)==0) break;
if (*vpmask==0 ||
*(vpmask+1)==0 ||
*(vpmask+is)==0 ||
*(vpmask+is+1)==0) break;
if (flag) {
cp = c + jj*is+ii;
cpmask = cmask + jj*is+ii;
if (*cpmask==0 ||
*(cpmask+1)==0 ||
*(cpmask+is)==0 ||
*(cpmask+is+1)==0) icol = 15;
else {
cv1 = *cp + (*(cp+1)-*cp)*xx;
cv2 = *(cp+is) + (*(cp+is+1)-*(cp+is))*xx;
cv = cv1 + (cv2-cv1)*yy;
icol = gxshdc(shdlvs,shdcls,shdcnt,cv);
}
if (icol!=scol && icol>-1) gxcolr(icol);
scol = icol;
}
uv1 = *up + (*(up+1)-*up)*xx;
uv2 = *(up+is) + (*(up+is+1)-*(up+is))*xx;
uv = uv1 + (uv2-uv1)*yy;
vv1 = *vp + (*(vp+1)-*vp)*xx;
vv2 = *(vp+is) + (*(vp+is+1)-*(vp+is))*xx;
vv = vv1 + (vv2-vv1)*yy;
auv = fabs(uv);
avv=fabs(vv);
if (auv<0.1 && avv<0.1) break;
if (auv>avv) {
vv = vv*fact/auv;
uv = uv*fact/auv;
} else {
uv = uv*fact/avv;
vv = vv*fact/avv;
}
x = x - uv;
y = y - vv;
ii1 = (gaint)(x*rscl);
ij1 = (gaint)(y*rscl);
ii1 = ij1*iss + ii1;
if (ii1<0 || ii1>=siz) break;
if (*(it+ii1)==1) break;
if (ii1!=iisav && iisav>-1) *(it+iisav) = 1;
if (ii1==iisav) iacc++;
else iacc = 0;
if (iacc>10) break;
iisav = ii1;
gxconv (x+1.0,y+1.0,&xx,&yy,3);
if (icol>-1) {
if (bflg) {
gxplot(xold,yold,3);
bflg=0;
}
gxplot (xx,yy,2);
} else bflg = 1;
xold = xx;
yold = yy;
acnt++;
if (acnt>20) {
if (icol>-1) strmar(xx,yy,xxsv,yysv);
acnt = 0;
}
xxsv = xx;
yysv = yy;
}
}
i2++;
if (i2==iss) {
i2 = 0;
j2++;
}
}
free (it);
}
