#include <stdio.h>

#include <u.h>
#include <libc.h>
#include <stdio.h>
#include "map.h"
#include "iplot.h"

#define NVERT 20 /* max number of vertices in a -v polygon */
#define HALFWIDTH 8192 /* output scaled to fit in -HALFWIDTH,HALFWIDTH */
#define LONGLINES (HALFWIDTH*4) /* permissible segment lengths */
#define SHORTLINES (HALFWIDTH/8)
#define SCALERATIO 10 /* of abs to rel data (see map(5)) */
#define RESOL 2. /* coarsest resolution for tracing grid (degrees) */
#define TWO_THRD 0.66666666666666667

int normproj(double, double, double *, double *);
int posproj(double, double, double *, double *);
int picut(struct place *, struct place *, double *);
double reduce(double);
short getshort(FILE *);
char *mapindex(char *);
proj projection;

static char *mapdir = "/lib/map"; /* default map directory */
struct file {
char *name;
char *color;
char *style;
};
static struct file dfltfile = {
"world", BLACK, SOLID /* default map */
};
static struct file *file = &dfltfile; /* list of map files */
static int nfile = 1; /* length of list */
static char *currcolor = BLACK; /* current color */
static char *gridcolor = BLACK;
static char *bordcolor = BLACK;

extern struct index index[];
int halfwidth = HALFWIDTH;

static int (*cut)(struct place *, struct place *, double *);
static int (*limb)(double*, double*, double);
static void dolimb(void);
static int onlimb;
static int poles;
static double orientation[3] = { 90., 0., 0. }; /* -o option */
static oriented; /* nonzero if -o option occurred */
static upright; /* 1 if orientation[0]==90, -1 if -90, else 0*/
static int delta = 1; /* -d setting */
static double limits[4] = { /* -l parameters */
-90., 90., -180., 180.
};
static double klimits[4] = { /* -k parameters */
-90., 90., -180., 180.
};
static int limcase;
static double rlimits[4]; /* limits expressed in radians */
static double lolat, hilat, lolon, hilon;
static double window[4] = { /* option -w */
-90., 90., -180., 180.
};
static windowed; /* nozero if option -w */
static struct vert { double x, y; } v[NVERT+2]; /*clipping polygon*/
static struct edge { double a, b, c; } e[NVERT]; /* coeffs for linear inequality */
static int nvert; /* number of vertices in clipping polygon */

static double rwindow[4]; /* window, expressed in radians */
static double params[2]; /* projection params */
/* bounds on output values before scaling; found by coarse survey */
static double xmin = 100.;
static double xmax = -100.;
static double ymin = 100.;
static double ymax = -100.;
static double xcent, ycent;
static double xoff, yoff;
double xrange, yrange;
static int left = -HALFWIDTH;
static int right = HALFWIDTH;
static int bottom = -HALFWIDTH;
static int top = HALFWIDTH;
static int longlines = SHORTLINES; /* drop longer segments */
static int shortlines = SHORTLINES;
static int bflag = 1; /* 0 for option -b */
static int s1flag = 0; /* 1 for option -s1 */
static int s2flag = 0; /* 1 for option -s2 */
static int rflag = 0; /* 1 for option -r */
static int kflag = 0; /* 1 if option -k occurred */
static int xflag = 0; /* 1 for option -x */
int vflag = 1; /* -1 if option -v occurred */
static double position[3]; /* option -p */
static double center[3] = {0., 0., 0.}; /* option -c */
static struct coord crot; /* option -c */
static double grid[3] = { 10., 10., RESOL }; /* option -g */
static double dlat, dlon; /* resolution for tracing grid in lat and lon */
static double scaling; /* to compute final integer output */
static struct file *track; /* options -t and -u */
static int ntrack; /* number of tracks present */
static char *symbolfile; /* option -y */

void clamp(double *px, double v);
void clipinit(void);
double diddle(struct place *, double, double);
double diddle(struct place *, double, double);
void dobounds(double, double, double, double, int);
void dogrid(double, double, double, double);
int duple(struct place *, double);
double fmax(double, double);
double fmin(double, double);
void getdata(char *);
int gridpt(double, double, int);
int inpoly(double, double);
int inwindow(struct place *);
void pathnames(void);
int pnorm(double);
void radbds(double *w, double *rw);
void revlon(struct place *, double);
void satellite(struct file *);
int seeable(double, double);
void windlim(void);
void realcut(void);

int
option(char *s)
{

if(s[0]=='-' && (s[1]<'0'||s[1]>'9'))
return(s[1]!='.'&&s[1]!=0);
else
return(0);
}

void
conv(int k, struct coord *g)
{
g->l = (0.0001/SCALERATIO)*k;
sincos(g);
}

int
main(int argc, char *argv[])
{
int i,k;
char *s, *t, *style;
double x, y;
double lat, lon;
double *wlim;
double dd;
if(sizeof(short)!=2)
abort(); /* getshort() won't work */
s = getenv("MAP");
if(s)
file[0].name = s;
s = getenv("MAPDIR");
if(s)
mapdir = s;
if(argc<=1)
error("usage: map projection params options");
for(k=0;index[k].name;k++) {
s = index[k].name;
t = argv[1];
while(*s == *t){
if(*s==0) goto found;
s++;
t++;
}
}
fprintf(stderr,"projections:\n");
for(i=0;index[i].name;i++) {
fprintf(stderr,"%s",index[i].name);
for(k=0; k<index[i].npar; k++)
fprintf(stderr," p%d", k);
fprintf(stderr,"\n");
}
exits("error");
found:
argv += 2;
argc -= 2;
cut = index[k].cut;
limb = index[k].limb;
poles = index[k].poles;
for(i=0;i<index[k].npar;i++) {
if(i>=argc||option(argv[i])) {
fprintf(stderr,"%s needs %d params\n",index[k].name,index[k].npar);
exits("error");
}
params[i] = atof(argv[i]);
}
argv += i;
argc -= i;
while(argc>0&&option(argv[0])) {
argc--;
argv++;
switch(argv[-1][1]) {
case 'm':
if(file == &dfltfile) {
file = 0;
nfile = 0;
}
while(argc && !option(*argv)) {
file = realloc(file,(nfile+1)*sizeof(*file));
file[nfile].name = *argv;
file[nfile].color = currcolor;
file[nfile].style = SOLID;
nfile++;
argv++;
argc--;
}
break;
case 'b':
bflag = 0;
for(nvert=0;nvert<NVERT&&argc>=2;nvert++) {
if(option(*argv))
break;
v[nvert].x = atof(*argv++);
argc--;
if(option(*argv))
break;
v[nvert].y = atof(*argv++);
argc--;
}
if(nvert>=NVERT)
error("too many clipping vertices");
break;
case 'g':
gridcolor = currcolor;
for(i=0;i<3&&argc>i&&!option(argv[i]);i++)
grid[i] = atof(argv[i]);
switch(i) {
case 0:
grid[0] = grid[1] = 0.;
break;
case 1:
grid[1] = grid[0];
}
argc -= i;
argv += i;
break;
case 't':
style = SOLID;
goto casetu;
case 'u':
style = DOTDASH;
casetu:
while(argc && !option(*argv)) {
track = realloc(track,(ntrack+1)*sizeof(*track));
track[ntrack].name = *argv;
track[ntrack].color = currcolor;
track[ntrack].style = style;
ntrack++;
argv++;
argc--;
}
break;
case 'r':
rflag++;
break;
case 's':
switch(argv[-1][2]) {
case '1':
s1flag++;
break;
case 0: /* compatibility */
case '2':
s2flag++;
}
break;
case 'o':
for(i=0;i<3&&i<argc&&!option(argv[i]);i++)
orientation[i] = atof(argv[i]);
oriented++;
argv += i;
argc -= i;
break;
case 'l':
bordcolor = currcolor;
for(i=0;i<argc&&i<4&&!option(argv[i]);i++)
limits[i] = atof(argv[i]);
argv += i;
argc -= i;
break;
case 'k':
kflag++;
for(i=0;i<argc&&i<4&&!option(argv[i]);i++)
klimits[i] = atof(argv[i]);
argv += i;
argc -= i;
break;
case 'd':
if(argc>0&&!option(argv[0])) {
delta = atoi(argv[0]);
argv++;
argc--;
}
break;
case 'w':
bordcolor = currcolor;
windowed++;
for(i=0;i<argc&&i<4&&!option(argv[i]);i++)
window[i] = atof(argv[i]);
argv += i;
argc -= i;
break;
case 'c':
for(i=0;i<3&&argc>i&&!option(argv[i]);i++)
center[i] = atof(argv[i]);
argc -= i;
argv += i;
break;
case 'p':
for(i=0;i<3&&argc>i&&!option(argv[i]);i++)
position[i] = atof(argv[i]);
argc -= i;
argv += i;
if(i!=3||position[2]<=0)
error("incomplete positioning");
break;
case 'y':
if(argc>0&&!option(argv[0])) {
symbolfile = argv[0];
argc--;
argv++;
}
break;
case 'v':
if(index[k].limb == 0)
error("-v does not apply here");
vflag = -1;
break;
case 'x':
xflag = 1;
break;
case 'C':
if(argc && !option(*argv)) {
currcolor = colorcode(*argv);
argc--;
argv++;
}
break;
}
}
if(argc>0)
error("error in arguments");
pathnames();
clamp(&limits[0],-90.);
clamp(&limits[1],90.);
clamp(&klimits[0],-90.);
clamp(&klimits[1],90.);
clamp(&window[0],-90.);
clamp(&window[1],90.);
radbds(limits,rlimits);
limcase = limits[2]<-180.?0:
limits[3]>180.?2:
1;
if(
window[0]>=window[1]||
window[2]>=window[3]||
window[0]>90.||
window[1]<-90.||
window[2]>180.||
window[3]<-180.)
error("unreasonable window");
windlim();
radbds(window,rwindow);
upright = orientation[0]==90? 1: orientation[0]==-90? -1: 0;
if(index[k].spheroid && !upright)
error("can't tilt the spheroid");
if(limits[2]>limits[3])
limits[3] += 360;
if(!oriented)
orientation[2] = (limits[2]+limits[3])/2;
orient(orientation[0],orientation[1],orientation[2]);
projection = (*index[k].prog)(params[0],params[1]);
if(projection == 0)
error("unreasonable projection parameters");
clipinit();
grid[0] = fabs(grid[0]);
grid[1] = fabs(grid[1]);
if(!kflag)
for(i=0;i<4;i++)
klimits[i] = limits[i];
if(klimits[2]>klimits[3])
klimits[3] += 360;
lolat = limits[0];
hilat = limits[1];
lolon = limits[2];
hilon = limits[3];
if(lolon>=hilon||lolat>=hilat||lolat<-90.||hilat>90.)
error("unreasonable limits");
wlim = kflag? klimits: window;
dlat = fmin(hilat-lolat,wlim[1]-wlim[0])/16;
dlon = fmin(hilon-lolon,wlim[3]-wlim[2])/32;
dd = fmax(dlat,dlon);
while(grid[2]>fmin(dlat,dlon)/2)
grid[2] /= 2;
realcut();
if(nvert<=0) {
for(lat=klimits[0];lat<klimits[1]+dd-FUZZ;lat+=dd) {
if(lat>klimits[1])
lat = klimits[1];
for(lon=klimits[2];lon<klimits[3]+dd-FUZZ;lon+=dd) {
i = (kflag?posproj:normproj)
(lat,lon+(lon<klimits[3]?FUZZ:-FUZZ),
&x,&y);
if(i*vflag <= 0)
continue;
if(x<xmin) xmin = x;
if(x>xmax) xmax = x;
if(y<ymin) ymin = y;
if(y>ymax) ymax = y;
}
}
} else {
for(i=0; i<nvert; i++) {
x = v[i].x;
y = v[i].y;
if(x<xmin) xmin = x;
if(x>xmax) xmax = x;
if(y<ymin) ymin = y;
if(y>ymax) ymax = y;
}
}
xrange = xmax - xmin;
yrange = ymax - ymin;
if(xrange<=0||yrange<=0)
error("map seems to be empty");
scaling = 2; /*plotting area from -1 to 1*/
if(position[2]!=0) {
if(posproj(position[0]-.5,position[1],&xcent,&ycent)==0||
posproj(position[0]+.5,position[1],&x,&y)==0)
error("unreasonable position");
scaling /= (position[2]*hypot(x-xcent,y-ycent));
if(posproj(position[0],position[1],&xcent,&ycent)==0)
error("unreasonable position");
} else {
scaling /= (xrange>yrange?xrange:yrange);
xcent = (xmin+xmax)/2;
ycent = (ymin+ymax)/2;
}
xoff = center[0]/scaling;
yoff = center[1]/scaling;
crot.l = center[2]*RAD;
sincos(&crot);
scaling *= HALFWIDTH*0.9;
if(symbolfile)
getsyms(symbolfile);
if(!s2flag) {
openpl();
erase();
}
range(left,bottom,right,top);
comment("grid","");
colorx(gridcolor);
pen(DOTTED);
if(grid[0]>0.)
for(lat=ceil(lolat/grid[0])*grid[0];
lat<=hilat;lat+=grid[0])
dogrid(lat,lat,lolon,hilon);
if(grid[1]>0.)
for(lon=ceil(lolon/grid[1])*grid[1];
lon<=hilon;lon+=grid[1])
dogrid(lolat,hilat,lon,lon);
comment("border","");
colorx(bordcolor);
pen(SOLID);
if(bflag) {
dolimb();
dobounds(lolat,hilat,lolon,hilon,0);
dobounds(window[0],window[1],window[2],window[3],1);
}
lolat = floor(limits[0]/10)*10;
hilat = ceil(limits[1]/10)*10;
lolon = floor(limits[2]/10)*10;
hilon = ceil(limits[3]/10)*10;
if(lolon>hilon)
hilon += 360.;
/*do tracks first so as not to lose the standard input*/
for(i=0;i<ntrack;i++) {
longlines = LONGLINES;
satellite(&track[i]);
longlines = shortlines;
}
for(i=0;i<nfile;i++) {
comment("mapfile",file[i].name);
colorx(file[i].color);
pen(file[i].style);
getdata(file[i].name);
}
move(right,bottom);
if(!s1flag)
closepl();
return 0;
}

/* Out of perverseness (really to recover from a dubious,
but documented, convention) the returns from projection
functions (-1 unplottable, 0 wrong sheet, 1 good) are
recoded into -1 wrong sheet, 0 unplottable, 1 good. */

int
fixproj(struct place *g, double *x, double *y)
{
int i = (*projection)(g,x,y);
return i<0? 0: i==0? -1: 1;
}

int
normproj(double lat, double lon, double *x, double *y)
{
int i;
struct place geog;
latlon(lat,lon,&geog);
/*
printp(&geog);
*/
normalize(&geog);
if(!inwindow(&geog))
return(-1);
i = fixproj(&geog,x,y);
if(rflag)
*x = -*x;
/*
printp(&geog);
fprintf(stderr,"%d %.3f %.3f\n",i,*x,*y);
*/
return(i);
}

int
posproj(double lat, double lon, double *x, double *y)
{
int i;
struct place geog;
latlon(lat,lon,&geog);
normalize(&geog);
i = fixproj(&geog,x,y);
if(rflag)
*x = -*x;
return(i);
}

int
inwindow(struct place *geog)
{
if(geog->nlat.l<rwindow[0]-FUZZ||
geog->nlat.l>rwindow[1]+FUZZ||
geog->wlon.l<rwindow[2]-FUZZ||
geog->wlon.l>rwindow[3]+FUZZ)
return(0);
else return(1);
}

int
inlimits(struct place *g)
{
if(rlimits[0]-FUZZ>g->nlat.l||
rlimits[1]+FUZZ<g->nlat.l)
return(0);
switch(limcase) {
case 0:
if(rlimits[2]+TWOPI-FUZZ>g->wlon.l&&
rlimits[3]+FUZZ<g->wlon.l)
return(0);
break;
case 1:
if(rlimits[2]-FUZZ>g->wlon.l||
rlimits[3]+FUZZ<g->wlon.l)
return(0);
break;
case 2:
if(rlimits[2]>g->wlon.l&&
rlimits[3]-TWOPI+FUZZ<g->wlon.l)
return(0);
break;
}
return(1);
}

long patch[18][36];

void
getdata(char *mapfile)
{
char *indexfile;
int kx,ky,c;
int k;
long b;
long *p;
int ip, jp;
int n;
struct place g;
int i, j;
double lat, lon;
int conn;
FILE *ifile, *xfile;

indexfile = mapindex(mapfile);
xfile = fopen(indexfile,"r");
if(xfile==NULL)
filerror("can't find map index", indexfile);
free(indexfile);
for(i=0,p=patch[0];i<18*36;i++,p++)
*p = 1;
while(!feof(xfile) && fscanf(xfile,"%d%d%ld",&i,&j,&b)==3)
patch[i+9][j+18] = b;
fclose(xfile);
ifile = fopen(mapfile,"r");
if(ifile==NULL)
filerror("can't find map data", mapfile);
for(lat=lolat;lat<hilat;lat+=10.)
for(lon=lolon;lon<hilon;lon+=10.) {
if(!seeable(lat,lon))
continue;
i = pnorm(lat);
j = pnorm(lon);
if((b=patch[i+9][j+18])&1)
continue;
fseek(ifile,b,0);
while((ip=getc(ifile))>=0&&(jp=getc(ifile))>=0){
if(ip!=(i&0377)||jp!=(j&0377))
break;
n = getshort(ifile);
conn = 0;
if(n > 0) { /* absolute coordinates */
kx = ky = 0; /* set */
for(k=0;k<n;k++){
kx = SCALERATIO*getshort(ifile);
ky = SCALERATIO*getshort(ifile);
if (((k%delta) != 0) && (k != (n-1)))
continue;
conv(kx,&g.nlat);
conv(ky,&g.wlon);
conn = plotpt(&g,conn);
}
} else { /* differential, scaled by SCALERATI0 */
n = -n;
kx = SCALERATIO*getshort(ifile);
ky = SCALERATIO*getshort(ifile);
for(k=0; k<n; k++) {
c = getc(ifile);
if(c&0200) c|= ~0177;
kx += c;
c = getc(ifile);
if(c&0200) c|= ~0177;
ky += c;
if(k%delta!=0&&k!=n-1)
continue;
conv(kx,&g.nlat);
conv(ky,&g.wlon);
conn = plotpt(&g,conn);
}
}
if(k==1) {
conv(kx,&g.nlat);
conv(ky,&g.wlon);
plotpt(&g,conn);
}
}
}
fclose(ifile);
}

int
seeable(double lat0, double lon0)
{
double x, y;
double lat, lon;
for(lat=lat0;lat<=lat0+10;lat+=2*grid[2])
for(lon=lon0;lon<=lon0+10;lon+=2*grid[2])
if(normproj(lat,lon,&x,&y)*vflag>0)
return(1);
return(0);
}

void
satellite(struct file *t)
{
char sym[50];
char lbl[50];
double scale;
register conn;
double lat,lon;
struct place place;
static FILE *ifile = stdin;
if(t->name[0]!='-'||t->name[1]!=0) {
fclose(ifile);
if((ifile=fopen(t->name,"r"))==NULL)
filerror("can't find track", t->name);
}
comment("track",t->name);
colorx(t->color);
pen(t->style);
for(;;) {
conn = 0;
while(!feof(ifile) && fscanf(ifile,"%lf%lf",&lat,&lon)==2){
latlon(lat,lon,&place);
if(fscanf(ifile,"%1s",lbl) == 1) {
if(strchr("+-.0123456789",*lbl)==0)
break;
ungetc(*lbl,ifile);
}
conn = plotpt(&place,conn);
}
if(feof(ifile))
return;
fscanf(ifile,"%[^\n]",lbl+1);
switch(*lbl) {
case '"':
if(plotpt(&place,conn))
text(lbl+1);
break;
case ':':
case '!':
if(sscanf(lbl+1,"%s %lf",sym,&scale) <= 1)
scale = 1;
if(plotpt(&place,conn?conn:-1)) {
int r = *lbl=='!'?0:rflag?-1:1;
pen(SOLID);
if(putsym(&place,sym,scale,r) == 0)
text(lbl);
pen(t->style);
}
break;
default:
if(plotpt(&place,conn))
text(lbl);
break;
}
}
}

int
pnorm(double x)
{
int i;
i = x/10.;
i %= 36;
if(i>=18) return(i-36);
if(i<-18) return(i+36);
return(i);
}

void
error(char *s)
{
fprintf(stderr,"map: \r\n%s\n",s);
exits("error");
}

void
filerror(char *s, char *f)
{
fprintf(stderr,"\r\n%s %s\n",s,f);
exits("error");
}

char *
mapindex(char *s)
{
char *t = malloc(strlen(s)+3);
strcpy(t,s);
strcat(t,".x");
return t;
}

#define NOPT 32767
static ox = NOPT, oy = NOPT;

int
cpoint(int xi, int yi, int conn)
{
int dx = abs(ox-xi);
int dy = abs(oy-yi);
if(!xflag && (xi<left||xi>=right || yi<bottom||yi>=top)) {
ox = oy = NOPT;
return 0;
}
if(conn == -1) /* isolated plotting symbol */
{}
else if(!conn)
point(xi,yi);
else {
if(dx+dy>longlines) {
ox = oy = NOPT; /* don't leap across cuts */
return 0;
}
if(dx || dy)
vec(xi,yi);
}
ox = xi, oy = yi;
return dx+dy<=2? 2: 1; /* 2=very near; see dogrid */
}

struct place oldg;

int
plotpt(struct place *g, int conn)
{
int kx,ky;
int ret;
double cutlon;
if(!inlimits(g)) {
return(0);
}
normalize(g);
if(!inwindow(g)) {
return(0);
}
switch((*cut)(g,&oldg,&cutlon)) {
case 2:
if(conn) {
ret = duple(g,cutlon)|duple(g,cutlon);
oldg = *g;
return(ret);
}
case 0:
conn = 0;
default: /* prevent diags about bad return value */
case 1:
oldg = *g;
ret = doproj(g,&kx,&ky);
if(ret==0 || !onlimb && ret*vflag<=0)
return(0);
ret = cpoint(kx,ky,conn);
return ret;
}
}

int
doproj(struct place *g, int *kx, int *ky)
{
int i;
double x,y,x1,y1;
/*fprintf(stderr,"dopr1 %f %f \n",g->nlat.l,g->wlon.l);*/
i = fixproj(g,&x,&y);
if(i == 0)
return(0);
if(rflag)
x = -x;
/*fprintf(stderr,"dopr2 %f %f\n",x,y);*/
if(!inpoly(x,y)) {
return 0;
}
x1 = x - xcent;
y1 = y - ycent;
x = (x1*crot.c - y1*crot.s + xoff)*scaling;
y = (x1*crot.s + y1*crot.c + yoff)*scaling;
*kx = x + (x>0?.5:-.5);
*ky = y + (y>0?.5:-.5);
return(i);
}

int
duple(struct place *g, double cutlon)
{
int kx,ky;
int okx,oky;
struct place ig;
revlon(g,cutlon);
revlon(&oldg,cutlon);
ig = *g;
invert(&ig);
if(!inlimits(&ig))
return(0);
if(doproj(g,&kx,&ky)*vflag<=0 ||
doproj(&oldg,&okx,&oky)*vflag<=0)
return(0);
cpoint(okx,oky,0);
cpoint(kx,ky,1);
return(1);
}

void
revlon(struct place *g, double cutlon)
{
g->wlon.l = reduce(cutlon-reduce(g->wlon.l-cutlon));
sincos(&g->wlon);
}

/* recognize problems of cuts
* move a point across cut to side of its predecessor
* if its very close to the cut
* return(0) if cut interrupts the line
* return(1) if line is to be drawn normally
* return(2) if line is so close to cut as to
* be properly drawn on both sheets
*/

int
picut(struct place *g, struct place *og, double *cutlon)
{
*cutlon = PI;
return(ckcut(g,og,PI));
}

int
nocut(struct place *g, struct place *og, double *cutlon)
{
USED(g, og, cutlon);
/*
#pragma ref g
#pragma ref og
#pragma ref cutlon
*/
return(1);
}

int
ckcut(struct place *g1, struct place *g2, double lon)
{
double d1, d2;
double f1, f2;
int kx,ky;
d1 = reduce(g1->wlon.l -lon);
d2 = reduce(g2->wlon.l -lon);
if((f1=fabs(d1))<FUZZ)
d1 = diddle(g1,lon,d2);
if((f2=fabs(d2))<FUZZ) {
d2 = diddle(g2,lon,d1);
if(doproj(g2,&kx,&ky)*vflag>0)
cpoint(kx,ky,0);
}
if(f1<FUZZ&&f2<FUZZ)
return(2);
if(f1>PI*TWO_THRD||f2>PI*TWO_THRD)
return(1);
return(d1*d2>=0);
}

double
diddle(struct place *g, double lon, double d)
{
double d1;
d1 = FUZZ/2;
if(d<0)
d1 = -d1;
g->wlon.l = reduce(lon+d1);
sincos(&g->wlon);
return(d1);
}

double
reduce(double lon)
{
if(lon>PI)
lon -= 2*PI;
else if(lon<-PI)
lon += 2*PI;
return(lon);
}

double tetrapt = 35.26438968; /* atan(1/sqrt(2)) */

void
dogrid(double lat0, double lat1, double lon0, double lon1)
{
double slat,slon,tlat,tlon;
register int conn, oconn;
slat = tlat = slon = tlon = 0;
if(lat1>lat0)
slat = tlat = fmin(grid[2],dlat);
else
slon = tlon = fmin(grid[2],dlon);;
conn = oconn = 0;
while(lat0<=lat1&&lon0<=lon1) {
conn = gridpt(lat0,lon0,conn);
if(projection==Xguyou&&slat>0) {
if(lat0<-45&&lat0+slat>-45)
conn = gridpt(-45.,lon0,conn);
else if(lat0<45&&lat0+slat>45)
conn = gridpt(45.,lon0,conn);
} else if(projection==Xtetra&&slat>0) {
if(lat0<-tetrapt&&lat0+slat>-tetrapt) {
gridpt(-tetrapt-.001,lon0,conn);
conn = gridpt(-tetrapt+.001,lon0,0);
}
else if(lat0<tetrapt&&lat0+slat>tetrapt) {
gridpt(tetrapt-.001,lon0,conn);
conn = gridpt(tetrapt+.001,lon0,0);
}
}
if(conn==0 && oconn!=0) {
if(slat+slon>.05) {
lat0 -= slat; /* steps too big */
lon0 -= slon; /* or near bdry */
slat /= 2;
slon /= 2;
conn = oconn = gridpt(lat0,lon0,conn);
} else
oconn = 0;
} else {
if(conn==2) {
slat = tlat;
slon = tlon;
conn = 1;
}
oconn = conn;
}
lat0 += slat;
lon0 += slon;
}
gridpt(lat1,lon1,conn);
}

static gridinv; /* nonzero when doing window bounds */

int
gridpt(double lat, double lon, int conn)
{
struct place g;
/*fprintf(stderr,"%f %f\n",lat,lon);*/
latlon(lat,lon,&g);
if(gridinv)
invert(&g);
return(plotpt(&g,conn));
}

/* win=0 ordinary grid lines, win=1 window lines */

void
dobounds(double lolat, double hilat, double lolon, double hilon, int win)
{
gridinv = win;
if(lolat>-90 || win && (poles&1)!=0)
dogrid(lolat+FUZZ,lolat+FUZZ,lolon,hilon);
if(hilat<90 || win && (poles&2)!=0)
dogrid(hilat-FUZZ,hilat-FUZZ,lolon,hilon);
if(hilon-lolon<360 || win && cut==picut) {
dogrid(lolat,hilat,lolon+FUZZ,lolon+FUZZ);
dogrid(lolat,hilat,hilon-FUZZ,hilon-FUZZ);
}
gridinv = 0;
}

static void
dolimb(void)
{
double lat, lon;
double res = fmin(dlat, dlon)/4;
int conn = 0;
int newconn;
if(limb == 0)
return;
onlimb = gridinv = 1;
for(;;) {
newconn = (*limb)(&lat, &lon, res);
if(newconn == -1)
break;
conn = gridpt(lat, lon, conn*newconn);
}
onlimb = gridinv = 0;
}

void
radbds(double *w, double *rw)
{
int i;
for(i=0;i<4;i++)
rw[i] = w[i]*RAD;
rw[0] -= FUZZ;
rw[1] += FUZZ;
rw[2] -= FUZZ;
rw[3] += FUZZ;
}

void
windlim(void)
{
double center = orientation[0];
double colat;
if(center>90)
center = 180 - center;
if(center<-90)
center = -180 - center;
if(fabs(center)>90)
error("unreasonable orientation");
colat = 90 - window[0];
if(center-colat>limits[0])
limits[0] = center - colat;
if(center+colat<limits[1])
limits[1] = center + colat;
}

short
getshort(FILE *f)
{
int c, r;
c = getc(f);
r = (c | getc(f)<<8);
if (r&0x8000)
r |= ~0xFFFF; /* in case short > 16 bits */
return r;
}

double
fmin(double x, double y)
{
return(x<y?x:y);
}

double
fmax(double x, double y)
{
return(x>y?x:y);
}

void
clamp(double *px, double v)
{
*px = (v<0?fmax:fmin)(*px,v);
}

void
pathnames(void)
{
int i;
char *t, *indexfile, *name;
FILE *f, *fx;
for(i=0; i<nfile; i++) {
name = file[i].name;
if(*name=='/')
continue;
indexfile = mapindex(name);
/* ansi equiv of unix access() call */
f = fopen(name, "r");
fx = fopen(indexfile, "r");
if(f) fclose(f);
if(fx) fclose(fx);
free(indexfile);
if(f && fx)
continue;
t = malloc(strlen(name)+strlen(mapdir)+2);
strcpy(t,mapdir);
strcat(t,"/");
strcat(t,name);
file[i].name = t;
}
}

void
clipinit(void)
{
register i;
double s,t;
if(nvert<=0)
return;
for(i=0; i<nvert; i++) { /*convert latlon to xy*/
if(normproj(v[i].x,v[i].y,&v[i].x,&v[i].y)==0)
error("invisible clipping vertex");
}
if(nvert==2) { /*rectangle with diag specified*/
nvert = 4;
v[2] = v[1];
v[1].x=v[0].x, v[1].y=v[2].y, v[3].x=v[2].x, v[3].y=v[0].y;
}
v[nvert] = v[0];
v[nvert+1] = v[1];
s = 0;
for(i=1; i<=nvert; i++) { /*test for convexity*/
t = (v[i-1].x-v[i].x)*(v[i+1].y-v[i].y) -
(v[i-1].y-v[i].y)*(v[i+1].x-v[i].x);
if(t<-FUZZ && s>=0) s = 1;
if(t>FUZZ && s<=0) s = -1;
if(-FUZZ<=t&&t<=FUZZ || t*s>0) {
s = 0;
break;
}
}
if(s==0)
error("improper clipping polygon");
for(i=0; i<nvert; i++) { /*edge equation ax+by=c*/
e[i].a = s*(v[i+1].y - v[i].y);
e[i].b = s*(v[i].x - v[i+1].x);
e[i].c = s*(v[i].x*v[i+1].y - v[i].y*v[i+1].x);
}
}

int
inpoly(double x, double y)
{
register i;
for(i=0; i<nvert; i++) {
register struct edge *ei = &e[i];
double val = x*ei->a + y*ei->b - ei->c;
if(val>10*FUZZ)
return(0);
}
return 1;
}

void
realcut()
{
struct place g;
double lat;

if(cut != picut) /* punt on unusual cuts */
return;
for(lat=window[0]; lat<=window[1]; lat+=grid[2]) {
g.wlon.l = PI;
sincos(&g.wlon);
g.nlat.l = lat*RAD;
sincos(&g.nlat);
if(!inwindow(&g)) {
break;
}
invert(&g);
if(inlimits(&g)) {
return;
}
}
longlines = shortlines = LONGLINES;
cut = nocut; /* not necessary; small eff. gain */
}