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Diffstat (limited to 'lisp/hl-line.el')
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diff --git a/lisp/hl-line.el b/lisp/hl-line.el new file mode 100644 index 0000000..26cfcc3 --- /dev/null +++ b/lisp/hl-line.el @@ -0,0 +1,298 @@ +;;; hl-line.el --- highlight the current line -*- lexical-binding:t -*- + +;; Copyright (C) 1998, 2000-2021 Free Software Foundation, Inc. + +;; Author: Dave Love <fx@gnu.org> +;; Maintainer: emacs-devel@gnu.org +;; Created: 1998-09-13 +;; Keywords: faces, frames, emulations + +;; This file is part of GNU Emacs. + +;; GNU Emacs is free software: you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. + +;; GNU Emacs is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. + +;;; Commentary: + +;; Provides a local minor mode (toggled by M-x hl-line-mode) and +;; a global minor mode (toggled by M-x global-hl-line-mode) to +;; highlight, on a suitable terminal, the line on which point is. The +;; global mode highlights the current line in the selected window only +;; (except when the minibuffer window is selected). This was +;; implemented to satisfy a request for a feature of Lesser Editors. +;; The local mode is sticky: it highlights the line about the buffer's +;; point even if the buffer's window is not selected. Caveat: the +;; buffer's point might be different from the point of a non-selected +;; window. Set the variable `hl-line-sticky-flag' to nil to make the +;; local mode behave like the global mode. + +;; You probably don't really want to use the global mode; if the +;; cursor is difficult to spot, try changing its color, relying on +;; `blink-cursor-mode' or both. The hookery used might affect +;; response noticeably on a slow machine. The local mode may be +;; useful in non-editing buffers such as Gnus or PCL-CVS though. + +;; An overlay is used. In the non-sticky cases, this overlay is +;; active only on the selected window. A hook is added to +;; `post-command-hook' to activate the overlay and move it to the line +;; about point. + +;; You could make variable `global-hl-line-mode' buffer-local and set +;; it to nil to avoid highlighting specific buffers, when the global +;; mode is used. + +;; By default the whole line is highlighted. The range of highlighting +;; can be changed by defining an appropriate function as the +;; buffer-local value of `hl-line-range-function'. + +;;; Code: + +(defvar-local hl-line-overlay nil + "Overlay used by Hl-Line mode to highlight the current line.") + +(defvar-local global-hl-line-overlay nil + "Overlay used by Global-Hl-Line mode to highlight the current line.") + +(defvar global-hl-line-overlays nil + "Overlays used by Global-Hl-Line mode in various buffers. +Global-Hl-Line keeps displaying one overlay in each buffer +when `global-hl-line-sticky-flag' is non-nil.") + +(defgroup hl-line nil + "Highlight the current line." + :version "21.1" + :group 'convenience) + +(defface hl-line + '((t :inherit highlight :extend t)) + "Default face for highlighting the current line in Hl-Line mode." + :version "22.1" + :group 'hl-line) + +(defcustom hl-line-face 'hl-line + "Face with which to highlight the current line in Hl-Line mode." + :type 'face + :group 'hl-line + :set (lambda (symbol value) + (set symbol value) + (dolist (buffer (buffer-list)) + (with-current-buffer buffer + (when (overlayp hl-line-overlay) + (overlay-put hl-line-overlay 'face hl-line-face)))) + (when (overlayp global-hl-line-overlay) + (overlay-put global-hl-line-overlay 'face hl-line-face)))) + +(defcustom hl-line-sticky-flag t + "Non-nil means the HL-Line mode highlight appears in all windows. +Otherwise Hl-Line mode will highlight only in the selected +window. Setting this variable takes effect the next time you use +the command `hl-line-mode' to turn Hl-Line mode on. + +This variable has no effect in Global Highlight Line mode. +For that, use `global-hl-line-sticky-flag'." + :type 'boolean + :version "22.1" + :group 'hl-line) + +(defcustom global-hl-line-sticky-flag nil + "Non-nil means the Global HL-Line mode highlight appears in all windows. +Otherwise Global Hl-Line mode will highlight only in the selected +window. Setting this variable takes effect the next time you use +the command `global-hl-line-mode' to turn Global Hl-Line mode on." + :type 'boolean + :version "24.1" + :group 'hl-line) + +(defvar hl-line-range-function nil + "If non-nil, function to call to return highlight range. +The function of no args should return a cons cell; its car value +is the beginning position of highlight and its cdr value is the +end position of highlight in the buffer. +It should return nil if there's no region to be highlighted. + +This variable is expected to be made buffer-local by modes.") + +(defvar hl-line-overlay-buffer nil + "Most recently visited buffer in which Hl-Line mode is enabled.") + +(defvar hl-line-overlay-priority -50 + "Priority used on the overlay used by hl-line.") + +;;;###autoload +(define-minor-mode hl-line-mode + "Toggle highlighting of the current line (Hl-Line mode). + +Hl-Line mode is a buffer-local minor mode. If +`hl-line-sticky-flag' is non-nil, Hl-Line mode highlights the +line about the buffer's point in all windows. Caveat: the +buffer's point might be different from the point of a +non-selected window. Hl-Line mode uses the function +`hl-line-highlight' on `post-command-hook' in this case. + +When `hl-line-sticky-flag' is nil, Hl-Line mode highlights the +line about point in the selected window only." + :group 'hl-line + (if hl-line-mode + (progn + ;; In case `kill-all-local-variables' is called. + (add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t) + (hl-line-highlight) + (setq hl-line-overlay-buffer (current-buffer)) + (add-hook 'post-command-hook #'hl-line-highlight nil t)) + (remove-hook 'post-command-hook #'hl-line-highlight t) + (hl-line-unhighlight) + (remove-hook 'change-major-mode-hook #'hl-line-unhighlight t))) + +(defun hl-line-make-overlay () + (let ((ol (make-overlay (point) (point)))) + (overlay-put ol 'priority hl-line-overlay-priority) ;(bug#16192) + (overlay-put ol 'face hl-line-face) + ol)) + +(defun hl-line-highlight () + "Activate the Hl-Line overlay on the current line." + (if hl-line-mode ; Might be changed outside the mode function. + (progn + (unless (overlayp hl-line-overlay) + (setq hl-line-overlay (hl-line-make-overlay))) ; To be moved. + (overlay-put hl-line-overlay + 'window (unless hl-line-sticky-flag (selected-window))) + (hl-line-move hl-line-overlay) + (hl-line-maybe-unhighlight)) + (hl-line-unhighlight))) + +(defun hl-line-unhighlight () + "Deactivate the Hl-Line overlay on the current line." + (when (overlayp hl-line-overlay) + (delete-overlay hl-line-overlay) + (setq hl-line-overlay nil))) + +(defun hl-line-maybe-unhighlight () + "Maybe deactivate the Hl-Line overlay on the current line. +Specifically, when `hl-line-sticky-flag' is nil deactivate all +such overlays in all buffers except the current one." + (let ((hlob hl-line-overlay-buffer) + (curbuf (current-buffer))) + (when (and (buffer-live-p hlob) + (not hl-line-sticky-flag) + (not (eq curbuf hlob)) + (not (minibufferp))) + (with-current-buffer hlob + (hl-line-unhighlight))) + (when (and (overlayp hl-line-overlay) + (eq (overlay-buffer hl-line-overlay) curbuf)) + (setq hl-line-overlay-buffer curbuf)))) + +;;;###autoload +(define-minor-mode global-hl-line-mode + "Toggle line highlighting in all buffers (Global Hl-Line mode). + +If `global-hl-line-sticky-flag' is non-nil, Global Hl-Line mode +highlights the line about the current buffer's point in all live +windows. + +Global-Hl-Line mode uses the function `global-hl-line-highlight' +on `post-command-hook'." + :global t + :group 'hl-line + (if global-hl-line-mode + (progn + ;; In case `kill-all-local-variables' is called. + (add-hook 'change-major-mode-hook #'global-hl-line-unhighlight) + (global-hl-line-highlight-all) + (add-hook 'post-command-hook #'global-hl-line-highlight)) + (global-hl-line-unhighlight-all) + (remove-hook 'post-command-hook #'global-hl-line-highlight) + (remove-hook 'change-major-mode-hook #'global-hl-line-unhighlight))) + +(defun global-hl-line-highlight () + "Highlight the current line in the current window." + (when global-hl-line-mode ; Might be changed outside the mode function. + (unless (window-minibuffer-p) + (unless (overlayp global-hl-line-overlay) + (setq global-hl-line-overlay (hl-line-make-overlay))) ; To be moved. + (unless (member global-hl-line-overlay global-hl-line-overlays) + (push global-hl-line-overlay global-hl-line-overlays)) + (overlay-put global-hl-line-overlay 'window + (unless global-hl-line-sticky-flag + (selected-window))) + (hl-line-move global-hl-line-overlay) + (global-hl-line-maybe-unhighlight)))) + +(defun global-hl-line-highlight-all () + "Highlight the current line in all live windows." + (walk-windows (lambda (w) + (with-current-buffer (window-buffer w) + (global-hl-line-highlight))) + nil t)) + +(defun global-hl-line-unhighlight () + "Deactivate the Global-Hl-Line overlay on the current line." + (when (overlayp global-hl-line-overlay) + (delete-overlay global-hl-line-overlay) + (setq global-hl-line-overlay nil))) + +(defun global-hl-line-maybe-unhighlight () + "Maybe deactivate the Global-Hl-Line overlay on the current line. +Specifically, when `global-hl-line-sticky-flag' is nil deactivate +all such overlays in all buffers except the current one." + (mapc (lambda (ov) + (let ((ovb (overlay-buffer ov))) + (when (and (not global-hl-line-sticky-flag) + (bufferp ovb) + (not (eq ovb (current-buffer))) + (not (minibufferp))) + (with-current-buffer ovb + (global-hl-line-unhighlight))))) + global-hl-line-overlays)) + +(defun global-hl-line-unhighlight-all () + "Deactivate all Global-Hl-Line overlays." + (mapc (lambda (ov) + (let ((ovb (overlay-buffer ov))) + (when (bufferp ovb) + (with-current-buffer ovb + (global-hl-line-unhighlight))))) + global-hl-line-overlays) + (setq global-hl-line-overlays nil)) + +(defun hl-line-move (overlay) + "Move the Hl-Line overlay. +If `hl-line-range-function' is non-nil, move the OVERLAY to the position +where the function returns. If `hl-line-range-function' is nil, fill +the line including the point by OVERLAY." + (let (tmp b e) + (if hl-line-range-function + (setq tmp (funcall hl-line-range-function) + b (car tmp) + e (cdr tmp)) + (setq tmp t + b (line-beginning-position) + e (line-beginning-position 2))) + (if tmp + (move-overlay overlay b e) + (move-overlay overlay 1 1)))) + +(defun hl-line-unload-function () + "Unload the Hl-Line library." + (global-hl-line-mode -1) + (save-current-buffer + (dolist (buffer (buffer-list)) + (set-buffer buffer) + (when hl-line-mode (hl-line-mode -1)))) + ;; continue standard unloading + nil) + +(provide 'hl-line) + +;;; hl-line.el ends here |