post.trm - modify outdated kludge for buggy ghostscript

Since 2003 (commits 647573e 3601de1) post.trm has had a work-around for a bug in ghostscript that limited the number of successive relative moves or lines. Furthermore it added a "stroke" command before continuing. Because this causes a spurious line if it occurs inside a newpath/closepath, the limit was set at 100 (later 250) segments on the assumption that no closed path longer than that would be generated. That assumption is no longer true. Now we do not apply this kludge if a path is active. Probably the entire mechanism is no longer needed, but this change is more conservative than removing it altogether.
c4a4c21af363248631122ecfd890342dcb68f850
commit c4a4c21af363248631122ecfd890342dcb68f850
diff --git a/term/post.trm b/term/post.trm
@@ -132,6 +132,7 @@ TERM_PUBLIC char *PS_escape_string(char *origstr, char *escapelist);
 
 TERM_PUBLIC void PS_path(int p);
 static TBOOLEAN PS_newpath = FALSE;
+static TBOOLEAN PS_inpath = FALSE;
 static TBOOLEAN ENHps_opened_string = FALSE;  /* try to cut out empty ()'s */
 
 TERM_PUBLIC void PS_layer(t_termlayer syncpoint);
@@ -1950,6 +1951,7 @@ doclip\n\
 	fprintf(gppsfile, "(%s) findfont %d scalefont setfont\n",
 		ps_params->font, (t->v_char));
     ps_path_count = 0;
+    PS_inpath = FALSE;
     PS_relative_ok = FALSE;
     PS_pen_x = PS_pen_y = -4000;
     PS_taken = 0;
@@ -2196,7 +2198,10 @@ PS_vector(unsigned int x, unsigned int y)
 	fputs(abso, gppsfile);
 	ps_path_count = 1;  /* If we set it to zero, it may never get flushed */
     }
-    /* Ghostscript has a "pile-up of rounding errors" bug: a sequence of many
+
+#define MAX_REL_PATHLEN 250
+    /* -2003-
+     * Ghostscript has a "pile-up of rounding errors" bug: a sequence of many
      * rmove's or rlineto's does not yield the same line as move's or lineto's.
      * Therefore, we periodically force an update of the absolute position.
      * There was a case when 400 rlineto's were too much, so let's set the limit
@@ -2205,10 +2210,14 @@ PS_vector(unsigned int x, unsigned int y)
      * lineto with no intervening 'stroke' is ridiculously slow to render.
      * So we stroke the partial line, update the position in absolute terms,
      * then continue.  This whole section can go away if ghostscript/gv is fixed.
+     * -2023-
+     * This is now causing more problems than justified by accommodating
+     * old versions of ghostscript/gv.  In particular if the "stroke" is added
+     * inside a path it produces an unwanted line back to the path start.
      */
-#define MAX_REL_PATHLEN 250
     if (ps_path_count >= MAX_REL_PATHLEN) {
-	fprintf(gppsfile, "stroke %d %d M\n", x, y);
+	if (!PS_inpath)
+	    fprintf(gppsfile, "stroke %d %d M\n", x, y);
 	ps_path_count = 1;
     }
 
@@ -4324,11 +4333,13 @@ PS_path(int p)
 	case 0:	/* Start new path */
 		PS_FLUSH_PATH;
 		PS_newpath = TRUE;
+		PS_inpath = TRUE;
 		break;
 
 	case 1: /* Close path */
 		fprintf(gppsfile, "Z ");
 		PS_FLUSH_PATH;
+		PS_inpath = FALSE;
 		break;
     }