Make header line in some modes be sensitive to display-line-numbers

* lisp/ruler-mode.el (ruler-mode-ruler, ruler-mode-window-col):
* lisp/emacs-lisp/tabulated-list.el (tabulated-list-init-header)
(tabulated-list-print-entry): Account for the width taken by
line-number display.  (Bug#27895)

2 files changed, 18 insertions, 3 deletions

diff --git a/lisp/emacs-lisp/tabulated-list.el b/lisp/emacs-lisp/tabulated-list.el
index b6b49b1bfa2..8ff5cdf18e8 100644
--- a/lisp/emacs-lisp/tabulated-list.el
+++ b/lisp/emacs-lisp/tabulated-list.el
@@ -194,6 +194,8 @@ Populated by `tabulated-list-init-header'.")
                         mouse-face highlight
                         keymap ,tabulated-list-sort-button-map))
         (cols nil))
+    (if display-line-numbers
+        (setq x (+ x (line-number-display-width) 2)))
     (push (propertize " " 'display `(space :align-to ,x)) cols)
     (dotimes (n (length tabulated-list-format))
       (let* ((col (aref tabulated-list-format n))
@@ -410,6 +412,8 @@ of column descriptors."
         (x     (max tabulated-list-padding 0))
         (ncols (length tabulated-list-format))
         (inhibit-read-only t))
+    (if display-line-numbers
+        (setq x (+ x (line-number-display-width) 2)))
     (if (> tabulated-list-padding 0)
         (insert (make-string x ?\s)))
     (let ((tabulated-list--near-rows ; Bind it if not bound yet (Bug#25506).
diff --git a/lisp/ruler-mode.el b/lisp/ruler-mode.el
index fdfd5c61be9..16277973d60 100644
--- a/lisp/ruler-mode.el
+++ b/lisp/ruler-mode.el
@@ -304,7 +304,10 @@ or remove a tab stop.  \\[ruler-mode-toggle-show-tab-stops] or
 
 (defsubst ruler-mode-window-col (n)
   "Return a column number relative to the selected window.
-N is a column number relative to selected frame."
+N is a column number relative to selected frame.
+If required, account for screen estate taken by `display-line-numbers'."
+  (if display-line-numbers
+      (setq n (- n (line-number-display-width) 2)))
   (- n
      (or (car (window-margins)) 0)
      (fringe-columns 'left)
@@ -665,7 +668,7 @@ Optional argument PROPS specifies other text properties to apply."
   (let* ((w (ruler-mode-text-scaled-window-width))
          (m (window-margins))
          (f (window-fringes))
-         (i 0)
+         (i (if display-line-numbers (+ (line-number-display-width) 2) 0))
          (j (ruler-mode-text-scaled-window-hscroll))
          ;; Setup the scrollbar, fringes, and margins areas.
          (lf (ruler-mode-space
@@ -701,7 +704,15 @@ Optional argument PROPS specifies other text properties to apply."
            ;; hence the need for `string-to-multibyte'.
            ;; http://lists.gnu.org/archive/html/emacs-devel/2017-05/msg00841.html
            (string-to-multibyte
-            (make-string w ruler-mode-basic-graduation-char))
+            ;; Make the part of header-line corresponding to the
+            ;; line-number display be blank, not filled with
+            ;; ruler-mode-basic-graduation-char.
+            (if display-line-numbers
+                (let* ((lndw (+ (line-number-display-width) 2))
+                       (s (make-string lndw ?\s)))
+                  (concat s (make-string (- w lndw)
+                                         ruler-mode-basic-graduation-char)))
+              (make-string w ruler-mode-basic-graduation-char)))
            'face 'ruler-mode-default
            'local-map ruler-mode-map
            'help-echo (cond