Handle truncate-lines in customize-group

* lisp/cus-edit.el (custom-group--draw-horizontal-line): New
function to draw horizontal lines which handles a non-nil value of
'truncate-lines'.  (Bug#25308)
(custom-group-value-create): Use it.

Co-authored-by: Jonas Bernoulli <jonas@bernoul.li>

1 files changed, 18 insertions, 16 deletions

diff --git a/lisp/cus-edit.el b/lisp/cus-edit.el
index b9fd3e0a2d4..081d4c9213e 100644
--- a/lisp/cus-edit.el
+++ b/lisp/cus-edit.el
@@ -4062,6 +4062,22 @@ If GROUPS-ONLY is non-nil, return only those members that are groups."
           (push entry members)))
       (nreverse members))))
 
+(defun custom-group--draw-horizontal-line ()
+  "Draw a horizontal line at point.
+This works for both graphical and text displays."
+  (let ((p (point)))
+    (insert "\n")
+    (put-text-property p (1+ p) 'face '(:underline t))
+    (overlay-put (make-overlay p (1+ p))
+                 'before-string
+                 (propertize "\n" 'face '(:underline t)
+                             'display
+                             (list 'space :align-to
+                                   `(+ (0 . right)
+                                       ,(min (window-hscroll)
+                                             (- (line-end-position)
+                                                (line-beginning-position)))))))))
+
 (defun custom-group-value-create (widget)
   "Insert a customize group for WIDGET in the current buffer."
   (unless (eq (widget-get widget :custom-state) 'hidden)
@@ -4188,15 +4204,7 @@ If GROUPS-ONLY is non-nil, return only those members that are groups."
 
           ;; Nested style.
           (t                            ;Visible.
-           ;; Draw a horizontal line (this works for both graphical
-           ;; and text displays):
-           (let ((p (point)))
-             (insert "\n")
-             (put-text-property p (1+ p) 'face '(:underline t))
-             (overlay-put (make-overlay p (1+ p))
-                          'before-string
-                          (propertize "\n" 'face '(:underline t)
-                                      'display '(space :align-to 999))))
+           (custom-group--draw-horizontal-line)
 
            ;; Add parent groups references above the group.
            (when (eq level 1)
@@ -4287,13 +4295,7 @@ If GROUPS-ONLY is non-nil, return only those members that are groups."
              (widget-put widget :children children)
              (custom-group-state-update widget))
            ;; End line
-           (let ((p (1+ (point))))
-             (insert "\n\n")
-             (put-text-property p (1+ p) 'face '(:underline t))
-             (overlay-put (make-overlay p (1+ p))
-                          'before-string
-                          (propertize "\n" 'face '(:underline t)
-                                      'display '(space :align-to 999))))))))
+           (custom-group--draw-horizontal-line)))))
 
 (defvar custom-group-menu
   `(("Set for Current Session" custom-group-set