Add graph, plot
diff --git a/src/cmd/plot/libplot/fill.c b/src/cmd/plot/libplot/fill.c
new file mode 100644
index 0000000..a33294e
--- /dev/null
+++ b/src/cmd/plot/libplot/fill.c
@@ -0,0 +1,167 @@
+/*
+ * fill -- polygon tiler
+ * Updating the edgelist from scanline to scanline could be quicker if no
+ * edges cross: we can just merge the incoming edges. If the scan-line
+ * filling routine were a parameter, we could do textured
+ * polygons, polyblt, and other such stuff.
+ */
+#include "mplot.h"
+typedef enum{
+ Odd=1,
+ Nonzero=~0
+}Windrule;
+typedef struct edge Edge;
+struct edge{
+ Point p; /* point of crossing current scan-line */
+ int maxy; /* scan line at which to discard edge */
+ int dx; /* x increment if x fraction<1 */
+ int dx1; /* x increment if x fraction>=1 */
+ int x; /* x fraction, scaled by den */
+ int num; /* x fraction increment for unit y change, scaled by den */
+ int den; /* x fraction increment for unit x change, scaled by num */
+ int dwind; /* increment of winding number on passing this edge */
+ Edge *next; /* next edge on current scanline */
+ Edge *prev; /* previous edge on current scanline */
+};
+static void insert(Edge *ep, Edge **yp){
+ while(*yp && (*yp)->p.x<ep->p.x) yp=&(*yp)->next;
+ ep->next=*yp;
+ *yp=ep;
+ if(ep->next){
+ ep->prev=ep->next->prev;
+ ep->next->prev=ep;
+ if(ep->prev)
+ ep->prev->next=ep;
+ }
+ else
+ ep->prev=0;
+}
+static void polygon(int cnt[], double *pts[], Windrule w, int v){
+ Edge *edges, *ep, *nextep, **ylist, **eylist, **yp;
+ Point p, q, p0, p1, p10;
+ int i, dy, nbig, y, left, right, wind, nwind, nvert;
+ int *cntp;
+ double **ptsp, *xp;
+ nvert=0;
+ for(cntp=cnt;*cntp;cntp++) nvert+=*cntp;
+ edges=(Edge *)malloc(nvert*sizeof(Edge));
+ if(edges==0){
+ NoSpace:
+ fprintf(stderr, "polygon: no space\n");
+ exits("malloc failed");
+ }
+ ylist=(Edge **)malloc(Dy(screen->r)*sizeof(Edge *));
+ if(ylist==0) goto NoSpace;
+ eylist=ylist+Dy(screen->r);
+ for(yp=ylist;yp!=eylist;yp++) *yp=0;
+ ep=edges;
+ for(cntp=cnt,ptsp=pts;*cntp;cntp++,ptsp++){
+ p.x=SCX((*ptsp)[*cntp*2-2]);
+ p.y=SCY((*ptsp)[*cntp*2-1]);
+ nvert=*cntp;
+ for(xp=*ptsp,i=0;i!=nvert;xp+=2,i++){
+ q=p;
+ p.x=SCX(xp[0]);
+ p.y=SCY(xp[1]);
+ if(p.y==q.y) continue;
+ if(p.y<q.y){
+ p0=p;
+ p1=q;
+ ep->dwind=1;
+ }
+ else{
+ p0=q;
+ p1=p;
+ ep->dwind=-1;
+ }
+ if(p1.y<=screen->r.min.y) continue;
+ if(p0.y>=screen->r.max.y) continue;
+ ep->p=p0;
+ if(p1.y>screen->r.max.y)
+ ep->maxy=screen->r.max.y;
+ else
+ ep->maxy=p1.y;
+ p10=subpt(p1, p0);
+ if(p10.x>=0){
+ ep->dx=p10.x/p10.y;
+ ep->dx1=ep->dx+1;
+ }
+ else{
+ p10.x=-p10.x;
+ ep->dx=-(p10.x/p10.y); /* this nonsense rounds toward zero */
+ ep->dx1=ep->dx-1;
+ }
+ ep->x=0;
+ ep->num=p10.x%p10.y;
+ ep->den=p10.y;
+ if(ep->p.y<screen->r.min.y){
+ dy=screen->r.min.y-ep->p.y;
+ ep->x+=dy*ep->num;
+ nbig=ep->x/ep->den;
+ ep->p.x+=ep->dx1*nbig+ep->dx*(dy-nbig);
+ ep->x%=ep->den;
+ ep->p.y=screen->r.min.y;
+ }
+ insert(ep, ylist+(ep->p.y-screen->r.min.y));
+ ep++;
+ }
+ }
+ left = 0;
+ for(yp=ylist,y=screen->r.min.y;yp!=eylist;yp++,y++){
+ wind=0;
+ for(ep=*yp;ep;ep=nextep){
+ nwind=wind+ep->dwind;
+ if(nwind&w){ /* inside */
+ if(!(wind&w)){
+ left=ep->p.x;
+ if(left<screen->r.min.x) left=screen->r.min.x;
+ }
+ }
+ else if(wind&w){
+ right=ep->p.x;
+ if(right>=screen->r.max.x) right=screen->r.max.x;
+#define BART_BUG_FIXED /* what goes on here?? -rob */
+#ifdef BART_BUG_FIXED
+ if(right>left)
+ line(screen, Pt(left, y), Pt(right, y), Endsquare, Endsquare, 0, getcolor(v), ZP);
+#else
+ if(right>left){
+ switch(v){
+ default:
+ segment(&screen, Pt(left, y), Pt(right, y),
+ ~0, D&~S);
+ segment(&screen, Pt(left, y), Pt(right, y),
+ v, f);
+ break;
+ case 0:
+ segment(&screen, Pt(left, y), Pt(right, y),
+ ~0, D&~S);
+ break;
+ case 3:
+ segment(&screen, Pt(left, y), Pt(right, y),
+ v, f);
+ break;
+ }
+ }
+#endif
+ }
+ wind=nwind;
+ nextep=ep->next;
+ if(++ep->p.y!=ep->maxy){
+ ep->x+=ep->num;
+ if(ep->x>=ep->den){
+ ep->x-=ep->den;
+ ep->p.x+=ep->dx1;
+ }
+ else
+ ep->p.x+=ep->dx;
+ insert(ep, yp+1);
+ }
+ }
+ }
+ free((char *)edges);
+ free((char *)ylist);
+}
+void fill(int num[], double *ff[]){
+ polygon(num, ff, Odd, e1->foregr);
+}
