Re: Patch to highlight current line number [nlinum.el]

[Kaushal Modi <kaushal.modi@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 7971 bytes --]

On Tue, Jul 19, 2016 at 8:28 AM Stefan Monnier <monnier@iro.umontreal.ca>
wrote:

> > I need the line-diff to get the line begin/end positions for the
> last-line.
>
> Exactly: if you have a marker showing you where is that "last-line", you
> don't need the line-diff.  If you really want the beg/end of that line,
> you `goto-char' to that marker and then use line-beginning-position and
> line-end-position from there with no argument.
>

Got it. I will work on that optimization as soon as I get chance.


> Oh, the gloabl-nlinum-mode was missing a ":group 'linum" argument!
>

OK, I added ":group 'nlinum" in the latest patch now.


> > ===== patch follows
>
> Please install it, and thank you very much.


The final (for now) patch is below. Thanks for all your help. Can you
please commit it? I do not have commit rights, but my copyright assignment
is on file.

=====
From c9c5e4a5a158cde292353ba8e0669e5877365a5a Mon Sep 17 00:00:00 2001
From: Kaushal Modi <kaushal.modi@gmail.com>
Date: Mon, 18 Jul 2016 17:42:45 -0400
Subject: [PATCH] Add ability to highlight current line number

* nlinum.el (nlinum-highlight-current-line): New defcustom to enable
highlighting current line number when non-nil (default is nil).
        (nlinum-current-line): New face for highlighting the current
line number.
---
 packages/nlinum/nlinum.el | 90
++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 78 insertions(+), 12 deletions(-)

diff --git a/packages/nlinum/nlinum.el b/packages/nlinum/nlinum.el
index 98c9cbc..0e7cf06 100644
--- a/packages/nlinum/nlinum.el
+++ b/packages/nlinum/nlinum.el
@@ -4,7 +4,7 @@

 ;; Author: Stefan Monnier <monnier@iro.umontreal.ca>
 ;; Keywords: convenience
-;; Version: 1.6
+;; Version: 1.7

 ;; This program is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -26,6 +26,11 @@

 ;;; News:

+;; v1.7:
+;; - Add ability to highlight current line number.
+;; - New custom variable `nlinum-highlight-current-line' and
+;;   face `nlinum-current-line'.
+
 ;; v1.3:
 ;; - New custom variable `nlinum-format'.
 ;; - Change in calling convention of `nlinum-format-function'.
@@ -36,11 +41,32 @@

 ;;; Code:

-(require 'linum)                        ;For its face.
+(require 'linum)                        ; for its face
+
+(defgroup nlinum nil
+  "Show line numbers in the margin, (hopefully) more efficiently."
+  :group 'convenience
+  :prefix "nlinum")
+
+(defcustom nlinum-highlight-current-line nil
+  "Whether the current line number should be highlighted.
+When non-nil, the current line number is highlighted in
`nlinum-current-line'
+face. "
+  :group 'nlinum
+  :type 'boolean)
+
+(defface nlinum-current-line
+  '((t :inherit linum :weight bold))
+  "Face for displaying current line."
+  :group 'nlinum)

 (defvar nlinum--width 2)
 (make-variable-buffer-local 'nlinum--width)

+(defvar nlinum--current-line 0
+  "Store current line number.")
+(make-variable-buffer-local 'nlinum--current-line)
+
 ;; (defvar nlinum--desc "")

 ;;;###autoload
@@ -53,9 +79,10 @@ if ARG is omitted or nil.
 Linum mode is a buffer-local minor mode."
   :lighter nil ;; (" NLinum" nlinum--desc)
   (jit-lock-unregister #'nlinum--region)
-  (remove-hook 'window-configuration-change-hook #'nlinum--setup-window t)
-  (remove-hook 'text-scale-mode-hook #'nlinum--setup-window t)
-  (remove-hook 'after-change-functions #'nlinum--after-change t)
+  (remove-hook 'window-configuration-change-hook #'nlinum--setup-window
:local)
+  (remove-hook 'text-scale-mode-hook #'nlinum--setup-window :local)
+  (remove-hook 'after-change-functions #'nlinum--after-change :local)
+  (remove-hook 'post-command-hook #'nlinum--current-line-update :local)
   (kill-local-variable 'nlinum--line-number-cache)
   (remove-overlays (point-min) (point-max) 'nlinum t)
   ;; (kill-local-variable 'nlinum--ol-counter)
@@ -64,10 +91,13 @@ Linum mode is a buffer-local minor mode."
     ;; FIXME: Another approach would be to make the mode permanent-local,
     ;; which might indeed be preferable.
     (add-hook 'change-major-mode-hook (lambda () (nlinum-mode -1)))
-    (add-hook 'text-scale-mode-hook #'nlinum--setup-window nil t)
-    (add-hook 'window-configuration-change-hook #'nlinum--setup-window nil
t)
-    (add-hook 'after-change-functions #'nlinum--after-change nil t)
-    (jit-lock-register #'nlinum--region t))
+    (add-hook 'text-scale-mode-hook #'nlinum--setup-window nil :local)
+    (add-hook 'window-configuration-change-hook #'nlinum--setup-window nil
:local)
+    (add-hook 'after-change-functions #'nlinum--after-change nil :local)
+    (if nlinum-highlight-current-line
+        (add-hook 'post-command-hook #'nlinum--current-line-update nil
:local)
+      (remove-hook 'post-command-hook #'nlinum--current-line-update
:local))
+    (jit-lock-register #'nlinum--region :contextual))
   (nlinum--setup-windows))

 (defun nlinum--face-height (face)
@@ -131,6 +161,35 @@ Linum mode is a buffer-local minor mode."
                          (point-min) (point-max) '(fontified)))))
                   (current-buffer)))

+(defun nlinum--current-line-update ()
+  "Update current line number."
+  (let ((last-line nlinum--current-line))
+    (setq nlinum--current-line (save-excursion
+                                 (unless (bolp)
+                                   (forward-line 0))
+                                 (nlinum--line-number-at-pos)))
+
+    (let ((line-diff (- last-line nlinum--current-line))
+          beg end)
+      ;; Remove the text properties only if the current line has changed
+      (when (not (zerop line-diff))
+        ;; If point is moving upwards
+        (if (natnump line-diff)
+            (progn
+              (setq beg (line-beginning-position)) ; beginning of the
current line
+              (setq end (line-end-position (1+ line-diff))) ; end of the
last line
+              ;; Handle the case of blank lines too.
+              (setq end (min (point-max) (1+ end))))
+          ;; If point is moving downwards
+          (setq beg (line-beginning-position (1+ line-diff))) ; beginning
of the last line
+          (setq end (line-end-position)) ; end of the current line
+          ;; Handle the case of blank lines too.
+          (setq end (min (point-max) (1+ end))))
+        ;; (message "curr-line:%d [beg/end:%d/%d] -- last-line:%d"
+        ;;          nlinum--current-line beg end last-line)
+        (with-silent-modifications
+          (remove-text-properties beg end '(fontified)))))))
+
 ;; (defun nlinum--ol-count ()
 ;;   (let ((i 0))
 ;;     (dolist (ol (overlays-in (point-min) (point-max)))
@@ -215,11 +274,17 @@ Used by the default `nlinum-format-function'."

 (defvar nlinum-format-function
   (lambda (line width)
-    (let ((str (format nlinum-format line)))
+    (let* ((is-current-line (= line nlinum--current-line))
+           (str (format nlinum-format line)))
       (when (< (length str) width)
         ;; Left pad to try and right-align the line-numbers.
         (setq str (concat (make-string (- width (length str)) ?\ ) str)))
-      (put-text-property 0 width 'face 'linum str)
+      (put-text-property 0 width 'face
+                         (if (and nlinum-highlight-current-line
+                                  is-current-line)
+                             'nlinum-current-line
+                           'linum)
+                         str)
       str))
   "Function to build the string representing the line number.
 Takes 2 arguments LINE and WIDTH, both of them numbers, and should return
@@ -260,7 +325,8 @@ it may cause the margin to be resized and line numbers
to be recomputed.")

 ;;;###autoload
 (define-globalized-minor-mode global-nlinum-mode nlinum-mode
-  (lambda () (unless (minibufferp) (nlinum-mode))))
+  (lambda () (unless (minibufferp) (nlinum-mode)))
+  :group 'nlinum)

 (provide 'nlinum)
 ;;; nlinum.el ends here
-- 
2.6.0.rc0.24.gec371ff


-- 

Kaushal Modi

[-- Attachment #2: Type: text/html, Size: 11522 bytes --]