Let's try this. It's BUGGERED.
diff --git a/src/cmd/grap/ticks.c b/src/cmd/grap/ticks.c
new file mode 100644
index 0000000..72fc06f
--- /dev/null
+++ b/src/cmd/grap/ticks.c
@@ -0,0 +1,492 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include "grap.h"
+#include "y.tab.h"
+
+#define MAXTICK 200
+int ntick = 0;
+double tickval[MAXTICK]; /* tick values (one axis at a time */
+char *tickstr[MAXTICK]; /* and labels */
+
+int tside = 0;
+int tlist = 0; /* 1 => explicit values given */
+int toffside = 0; /* no ticks on these sides */
+int goffside = 0; /* no ticks on grid on these sides */
+int tick_dir = OUT;
+double ticklen = TICKLEN; /* default tick length */
+int autoticks = LEFT|BOT;
+int autodir = 0; /* set LEFT, etc. if automatic ticks go in */
+
+void savetick(double f, char *s) /* remember tick location and label */
+{
+ if (ntick >= MAXTICK)
+ ERROR "too many ticks (%d)", MAXTICK FATAL;
+ tickval[ntick] = f;
+ tickstr[ntick] = s;
+ ntick++;
+}
+
+void dflt_tick(double f)
+{
+ if (f >= 0.0)
+ savetick(f, tostring("%g"));
+ else
+ savetick(f, tostring("\\%g"));
+}
+
+void tickside(int n) /* remember which side these ticks/gridlines go on */
+{
+ tside |= n;
+}
+
+void tickoff(int side) /* remember explicit sides */
+{
+ toffside |= side;
+}
+
+void gridtickoff(void) /* turn grid ticks off on the side previously specified (ugh) */
+{
+ goffside = tside;
+}
+
+void setlist(void) /* remember that there was an explicit list */
+{
+ tlist = 1;
+}
+
+void tickdir(int dir, double val, int explicit) /* remember in/out [expr] */
+{
+ tick_dir = dir;
+ if (explicit)
+ ticklen = val;
+}
+
+void ticks(void) /* set autoticks after ticks statement */
+{
+ /* was there an explicit "ticks [side] off"? */
+ if (toffside)
+ autoticks &= ~toffside;
+ /* was there an explicit list? (eg "ticks at ..." or "ticks from ...") */
+ if (tlist) {
+ if (tside & (BOT|TOP))
+ autoticks &= ~(BOT|TOP);
+ if (tside & (LEFT|RIGHT))
+ autoticks &= ~(LEFT|RIGHT);
+ }
+ /* was there a side without a list? (eg "ticks left in") */
+ if (tside && !tlist) {
+ if (tick_dir == IN)
+ autodir |= tside;
+ if (tside & (BOT|TOP))
+ autoticks = (autoticks & ~(BOT|TOP)) | (tside & (BOT|TOP));
+ if (tside & (LEFT|RIGHT))
+ autoticks = (autoticks & ~(LEFT|RIGHT)) | (tside & (LEFT|RIGHT));
+ }
+ tlist = tside = toffside = goffside = 0;
+ tick_dir = OUT;
+}
+
+double modfloor(double f, double t)
+{
+ t = fabs(t);
+ return floor(f/t) * t;
+}
+
+double modceil(double f, double t)
+{
+ t = fabs(t);
+ return ceil(f/t) * t;
+}
+
+double xtmin, xtmax; /* range of ticks */
+double ytmin, ytmax;
+double xquant, xmult; /* quantization & scale for auto x ticks */
+double yquant, ymult;
+double lograt = 5;
+
+void do_autoticks(Obj *p) /* make set of ticks for default coord only */
+{
+ double x, xl, xu, q;
+
+ if (p == NULL)
+ return;
+ fprintf(tfd, "Autoticks:\t# x %g..%g, y %g..%g",
+ p->pt.x, p->pt1.x, p->pt.y, p->pt1.y);
+ fprintf(tfd, "; xt %g,%g, yt %g,%g, xq,xm = %g,%g, yq,ym = %g,%g\n",
+ xtmin, xtmax, ytmin, ytmax, xquant, xmult, yquant, ymult);
+ if ((autoticks & (BOT|TOP)) && p->pt1.x >= p->pt.x) { /* make x ticks */
+ q = xquant;
+ xl = p->pt.x;
+ xu = p->pt1.x;
+ if (xl >= xu)
+ dflt_tick(xl);
+ else if ((p->log & XFLAG) && xu/xl >= lograt) {
+ for (x = q; x < xu; x *= 10) {
+ logtick(x, xl, xu);
+ if (xu/xl <= 100) {
+ logtick(2*x, xl, xu);
+ logtick(5*x, xl, xu);
+ }
+ }
+ } else {
+ xl = modceil(xtmin - q/100, q);
+ xu = modfloor(xtmax + q/100, q) + q/2;
+ for (x = xl; x <= xu; x += q)
+ dflt_tick(x);
+ }
+ tside = autoticks & (BOT|TOP);
+ ticklist(p, 0);
+ }
+ if ((autoticks & (LEFT|RIGHT)) && p->pt1.y >= p->pt.y) { /* make y ticks */
+ q = yquant;
+ xl = p->pt.y;
+ xu = p->pt1.y;
+ if (xl >= xu)
+ dflt_tick(xl);
+ else if ((p->log & YFLAG) && xu/xl >= lograt) {
+ for (x = q; x < xu; x *= 10) {
+ logtick(x, xl, xu);
+ if (xu/xl <= 100) {
+ logtick(2*x, xl, xu);
+ logtick(5*x, xl, xu);
+ }
+ }
+ } else {
+ xl = modceil(ytmin - q/100, q);
+ xu = modfloor(ytmax + q/100, q) + q/2;
+ for (x = xl; x <= xu; x += q)
+ dflt_tick(x);
+ }
+ tside = autoticks & (LEFT|RIGHT);
+ ticklist(p, 0);
+ }
+}
+
+void logtick(double v, double lb, double ub)
+{
+ float slop = 1.0; /* was 1.001 */
+
+ if (slop * lb <= v && ub >= slop * v)
+ dflt_tick(v);
+}
+
+Obj *setauto(void) /* compute new min,max, and quant & mult */
+{
+ Obj *p, *q;
+
+ if ((q = lookup("lograt",0)) != NULL)
+ lograt = q->fval;
+ for (p = objlist; p; p = p->next)
+ if (p->type == NAME && strcmp(p->name,dflt_coord) == 0)
+ break;
+ if (p) {
+ if ((p->log & XFLAG) && p->pt1.x/p->pt.x >= lograt)
+ autolog(p, 'x');
+ else
+ autoside(p, 'x');
+ if ((p->log & YFLAG) && p->pt1.y/p->pt.y >= lograt)
+ autolog(p, 'y');
+ else
+ autoside(p, 'y');
+ }
+ return p;
+}
+
+void autoside(Obj *p, int side)
+{
+ double r, s, d, ub, lb;
+
+ if (side == 'x') {
+ xtmin = lb = p->pt.x;
+ xtmax = ub = p->pt1.x;
+ } else {
+ ytmin = lb = p->pt.y;
+ ytmax = ub = p->pt1.y;
+ }
+ if (ub <= lb)
+ return; /* cop out on little ranges */
+ d = ub - lb;
+ r = s = 1;
+ while (d * s < 10)
+ s *= 10;
+ d *= s;
+ while (10 * r < d)
+ r *= 10;
+ if (r > d/3)
+ r /= 2;
+ else if (r <= d/6)
+ r *= 2;
+ if (side == 'x') {
+ xquant = r / s;
+ } else {
+ yquant = r / s;
+ }
+}
+
+void autolog(Obj *p, int side)
+{
+ double r, s, t, ub, lb;
+ int flg;
+
+ if (side == 'x') {
+ xtmin = lb = p->pt.x;
+ xtmax = ub = p->pt1.x;
+ flg = p->coord & XFLAG;
+ } else {
+ ytmin = lb = p->pt.y;
+ ytmax = ub = p->pt1.y;
+ flg = p->coord & YFLAG;
+ }
+ for (s = 1; lb * s < 1; s *= 10)
+ ;
+ lb *= s;
+ ub *= s;
+ for (r = 1; 10 * r < lb; r *= 10)
+ ;
+ for (t = 1; t < ub; t *= 10)
+ ;
+ if (side == 'x')
+ xquant = r / s;
+ else
+ yquant = r / s;
+ if (flg)
+ return;
+ if (ub / lb < 100) {
+ if (lb >= 5 * r)
+ r *= 5;
+ else if (lb >= 2 * r)
+ r *= 2;
+ if (ub * 5 <= t)
+ t /= 5;
+ else if (ub * 2 <= t)
+ t /= 2;
+ if (side == 'x') {
+ xtmin = r / s;
+ xtmax = t / s;
+ } else {
+ ytmin = r / s;
+ ytmax = t / s;
+ }
+ }
+}
+
+void iterator(double from, double to, int op, double by, char *fmt) /* create an iterator */
+{
+ double x;
+
+ /* should validate limits, etc. */
+ /* punt for now */
+
+ dprintf("iterate from %g to %g by %g, op = %c, fmt=%s\n",
+ from, to, by, op, fmt ? fmt : "");
+ switch (op) {
+ case '+':
+ case ' ':
+ for (x = from; x <= to + (SLOP-1) * by; x += by)
+ if (fmt)
+ savetick(x, tostring(fmt));
+ else
+ dflt_tick(x);
+ break;
+ case '-':
+ for (x = from; x >= to; x -= by)
+ if (fmt)
+ savetick(x, tostring(fmt));
+ else
+ dflt_tick(x);
+ break;
+ case '*':
+ for (x = from; x <= SLOP * to; x *= by)
+ if (fmt)
+ savetick(x, tostring(fmt));
+ else
+ dflt_tick(x);
+ break;
+ case '/':
+ for (x = from; x >= to; x /= by)
+ if (fmt)
+ savetick(x, tostring(fmt));
+ else
+ dflt_tick(x);
+ break;
+ }
+ if (fmt)
+ free(fmt);
+}
+
+void ticklist(Obj *p, int explicit) /* fire out the accumulated ticks */
+ /* 1 => list, 0 => auto */
+{
+ if (p == NULL)
+ return;
+ fprintf(tfd, "Ticks_%s:\n\tticklen = %g\n", p->name, ticklen);
+ print_ticks(TICKS, explicit, p, "ticklen", "");
+}
+
+void print_ticks(int type, int explicit, Obj *p, char *lenstr, char *descstr)
+{
+ int i, logflag, inside;
+ char buf[100];
+ double tv;
+
+ for (i = 0; i < ntick; i++) /* any ticks given explicitly? */
+ if (tickstr[i] != NULL)
+ break;
+ if (i >= ntick && type == TICKS) /* no, so use values */
+ for (i = 0; i < ntick; i++) {
+ if (tickval[i] >= 0.0)
+ sprintf(buf, "%g", tickval[i]);
+ else
+ sprintf(buf, "\\-%g", -tickval[i]);
+ tickstr[i] = tostring(buf);
+ }
+ else
+ for (i = 0; i < ntick; i++) {
+ if (tickstr[i] != NULL) {
+ sprintf(buf, tickstr[i], tickval[i]);
+ free(tickstr[i]);
+ tickstr[i] = tostring(buf);
+ }
+ }
+ logflag = sidelog(p->log, tside);
+ for (i = 0; i < ntick; i++) {
+ tv = tickval[i];
+ halfrange(p, tside, tv);
+ if (logflag) {
+ if (tv <= 0.0)
+ ERROR "can't take log of tick value %g", tv FATAL;
+ logit(tv);
+ }
+ if (type == GRID)
+ inside = LEFT|RIGHT|TOP|BOT;
+ else if (explicit)
+ inside = (tick_dir == IN) ? tside : 0;
+ else
+ inside = autodir;
+ if (tside & BOT)
+ maketick(type, p->name, BOT, inside, tv, tickstr[i], lenstr, descstr);
+ if (tside & TOP)
+ maketick(type, p->name, TOP, inside, tv, tickstr[i], lenstr, descstr);
+ if (tside & LEFT)
+ maketick(type, p->name, LEFT, inside, tv, tickstr[i], lenstr, descstr);
+ if (tside & RIGHT)
+ maketick(type, p->name, RIGHT, inside, tv, tickstr[i], lenstr, descstr);
+ if (tickstr[i]) {
+ free(tickstr[i]);
+ tickstr[i] = NULL;
+ }
+ }
+ ntick = 0;
+}
+
+void maketick(int type, char *name, int side, int inflag, double val, char *lab, char *lenstr, char *descstr)
+{
+ char *sidestr, *td;
+
+ fprintf(tfd, "\tline %s ", descstr);
+ inflag &= side;
+ switch (side) {
+ case BOT:
+ case 0:
+ td = inflag ? "up" : "down";
+ fprintf(tfd, "%s %s from (x_%s(%g),0)", td, lenstr, name, val);
+ break;
+ case TOP:
+ td = inflag ? "down" : "up";
+ fprintf(tfd, "%s %s from (x_%s(%g),frameht)", td, lenstr, name, val);
+ break;
+ case LEFT:
+ td = inflag ? "right" : "left";
+ fprintf(tfd, "%s %s from (0,y_%s(%g))", td, lenstr, name, val);
+ break;
+ case RIGHT:
+ td = inflag ? "left" : "right";
+ fprintf(tfd, "%s %s from (framewid,y_%s(%g))", td, lenstr, name, val);
+ break;
+ }
+ fprintf(tfd, "\n");
+ if (type == GRID && (side & goffside)) /* wanted no ticks on grid */
+ return;
+ sidestr = tick_dir == IN ? "start" : "end";
+ if (lab != NULL) {
+ /* BUG: should fix size of lab here */
+ double wid = strlen(lab)/7.5 + (tick_dir == IN ? 0 : 0.1); /* estimate width at 15 chars/inch */
+ switch (side) {
+ case BOT: case 0:
+ /* can drop "box invis" with new pic */
+ fprintf(tfd, "\tbox invis \"%s\" ht .25 wid 0 with .n at last line.%s",
+ lab, sidestr);
+ break;
+ case TOP:
+ fprintf(tfd, "\tbox invis \"%s\" ht .2 wid 0 with .s at last line.%s",
+ lab, sidestr);
+ break;
+ case LEFT:
+ fprintf(tfd, "\t\"%s \" wid %.2f rjust at last line.%s",
+ lab, wid, sidestr);
+ break;
+ case RIGHT:
+ fprintf(tfd, "\t\" %s\" wid %.2f ljust at last line.%s",
+ lab, wid, sidestr);
+ break;
+ }
+ /* BUG: works only if "down x" comes before "at wherever" */
+ lab_adjust();
+ fprintf(tfd, "\n");
+ }
+}
+
+Attr *grid_desc = 0;
+
+void griddesc(Attr *a)
+{
+ grid_desc = a;
+}
+
+void gridlist(Obj *p)
+{
+ char *framestr;
+
+ if ((tside & (BOT|TOP)) || tside == 0)
+ framestr = "frameht";
+ else
+ framestr = "framewid";
+ fprintf(tfd, "Grid_%s:\n", p->name);
+ tick_dir = IN;
+ print_ticks(GRID, 0, p, framestr, desc_str(grid_desc));
+ if (grid_desc) {
+ freeattr(grid_desc);
+ grid_desc = 0;
+ }
+}
+
+char *desc_str(Attr *a) /* convert DOT to "dotted", etc. */
+{
+ static char buf[50], *p;
+
+ if (a == NULL)
+ return p = "";
+ switch (a->type) {
+ case DOT: p = "dotted"; break;
+ case DASH: p = "dashed"; break;
+ case INVIS: p = "invis"; break;
+ default: p = "";
+ }
+ if (a->fval != 0.0) {
+ sprintf(buf, "%s %g", p, a->fval);
+ return buf;
+ } else
+ return p;
+}
+
+sidelog(int logflag, int side) /* figure out whether to scale a side */
+{
+ if ((logflag & XFLAG) && ((side & (BOT|TOP)) || side == 0))
+ return 1;
+ else if ((logflag & YFLAG) && (side & (LEFT|RIGHT)))
+ return 1;
+ else
+ return 0;
+}
