--- src/pstree.c.orig	2019-11-12 11:23:38.000000000 +0100
+++ src/pstree.c	2020-12-31 10:43:59.650348130 +0100
@@ -71,6 +71,7 @@
 #define UTF_HD        "\342\224\254"        /* U+252C, Horizontal and down */
 
 #define VT_BEG        "\033(0\017"        /* use graphic chars */
+#define VT_LEN      4
 #define VT_END        "\033(B"        /* back to normal char set */
 #define VT_V        "x"                /* see UTF definitions above */
 #define VT_VR        "t"
@@ -470,6 +471,27 @@
     out_string("'");
 }
 
+/*
+ * Only affects vt100 line drawing mode: Do not count the strlen of
+ * VT_BEG to prevent doing end-of-line way too early:
+ */
+static void
+out_sym (const char *str)
+{
+  int seq = 0;
+  if (sym == &sym_vt100 && *str == '\033') {
+    seq = 1;
+    if (cur_x <= output_width || !trunc)
+      cur_x -= VT_LEN;
+  }
+  out_string(str);
+  if (seq) {
+      str = VT_END;
+      while (*str)
+        putchar (*str++);
+  }
+}
+
 static void out_newline(void)
 {
     if (last_char && cur_x == output_width)
@@ -705,11 +727,12 @@
         for (lvl = 0; lvl < level; lvl++) {
             for (i = width[lvl] + 1; i; i--)
                 out_char(' ');
-            out_string(lvl ==
-                       level -
-                       1 ? last ? sym->last_2 : sym->branch_2 : more[lvl +
-                                                                     1] ?
-                       sym->vert_2 : sym->empty_2);
+                /*
+                * Replace all three symbol-drawing calls with calls to out_sym()
+                * to handle VT100 line drawing sequences if VT100 mode is active:
+                */
+                out_sym(lvl == level - 1 ? last ? sym->last_2 : sym->branch_2 :
+                more[lvl + 1] ? sym->vert_2 : sym->empty_2);
         }
 
     if (rep < 2)
@@ -819,7 +842,7 @@
     }
     width[level] = comm_len + cur_x - offset + add;
     if (cur_x >= output_width && trunc) {
-        out_string(sym->first_3);
+        out_sym(sym->first_3);
         out_string("+");
         out_newline();
         return;
@@ -843,7 +866,7 @@
                 }
         }
         if (first) {
-            out_string(next ? sym->first_3 : sym->single_3);
+            out_sym(next ? sym->first_3 : sym->single_3);
             first = 0;
         }
         dump_tree(walk->child, level + 1, count + 1,